Need a Nest Controller: File and Stream Controller

=====================================================

In this lesson, we will learn how to create a customized controller in NestJS that can download files. We will go through an example where we need to download a package.json file from a CRUN project and save it on the user's computer.

### Downloading Files without Extension

When you download a file using the `download` method, it downloads only the text content of the file without including the extension. For example, if we have a package.json file with the following contents:

```json

{

"name": "example",

"version": "1.0.0",

"description": "Example project"

}

```

The downloaded file will be saved as a plain text file without the .json extension.

### Downloading Files with Extension

To download files with their original extensions, we need to use the `stream` method and specify the content type of the file. For example, if we have an image file, we can specify the content type as 'image/jpeg' or 'application/json' for a JSON file.

Here's how you can create a new controller that downloads files:

```javascript

import { Controller, Get, Post, Req, Res } from '@nestjs/common';

import { FileService } from './file.service';

@Controller('files')

export class FilesController {

constructor(private readonly fileService: FileService) {}

@Get(':fileName')

async downloadFile(@Req() req, @Res() res) {

const fileName = req.params.fileName;

const fileExtension = '.json';

const filePath = 'path/to/file';

// Download the file using stream method

const fileStream = this.fileService.readFile(filePath);

// Set the response headers

res.set({

'Content-Disposition': `attachment; filename=${fileName}${fileExtension}`,

'Content-Type': 'application/json',

});

return fileStream;

}

}

```

In this example, we create a new controller with an endpoint `/files/:fileName`. When a request is made to this endpoint, the `downloadFile` method is called. This method downloads the file using the `stream` method and sets the response headers accordingly.

### Downloading Package.json File

To download the package.json file from a CRUN project, we can use the same approach as above. We need to specify the content type as 'application/json' and set the response headers accordingly.

Here's an example of how you can create a new method in the `FilesController` class that downloads the package.json file:

```javascript

import { Controller, Get, Post, Req, Res } from '@nestjs/common';

import { FileService } from './file.service';

@Controller('files')

export class FilesController {

constructor(private readonly fileService: FileService) {}

@Get(':fileName')

async downloadFile(@Req() req, @Res() res) {

const fileName = req.params.fileName;

const fileExtension = '.json';

const filePath = 'path/to/file';

// Download the file using stream method

const fileStream = this.fileService.readFile(filePath);

// Set the response headers

res.set({

'Content-Disposition': `attachment; filename=${fileName}${fileExtension}`,

'Content-Type': 'application/json',

});

return fileStream;

}

@Get('package.json')

async downloadPackageJson(@Req() req, @Res() res) {

const fileName = 'package.json';

const filePath = 'path/to/package.json';

// Download the package.json file using stream method

const fileStream = this.fileService.readFile(filePath);

// Set the response headers

res.set({

'Content-Disposition': `attachment; filename=${fileName}`,

'Content-Type': 'application/json',

});

return fileStream;

}

}

```

In this example, we create a new method called `downloadPackageJson` that downloads the package.json file from a specific path. The response headers are set to indicate that the downloaded file is an attachment with the filename `package.json`.

"WEBVTTKind: captionsLanguage: enlearn the fundamentals of nestjs by building the back end of a Spotify clone nestjs is a framework for building efficient scalable node.js web applications you'll learn how to design a database create rest apis and deploy the apis to production how did Alie develop this course welcome to my course nestjs let's talk about what is nestjs nestjs is used to build server side application in node.js it is built on the top of node.js expressjs and typescript the major difference between nestjs and other nodejs framework is this framework is using typescript and it is using the angular architecture angular Concepts on the pack if you familiar with angular concept you can work with nestjs is very easily why they are using the angular concept because if you use the angular architecture Concept in the back end you can organize your project in a easy way the development would be easy the contribution for other developers would be easy in sjs look at the documentation you will find the controllers providers modules middleware exception filter pipes guards inter interceptors and custom decorators all of these are Concepts in angular why they created nests if you have worked with Express you don't have any structure like you don't have any best practice to organize the backend project so they created the structure architecture level they designed the architecture to build server side applications in nodejs and typescript under the it is using expressjs and typescript so they are just solving the architecture problem when you build the large application in nodejs we backend web application in nodejs when your code base is increasing day by day it's hard to follow specific architecture that's why they have created the nestjs if you follow the nests you will see hey we need a controller we need a provider we need modules we can break application into multiple modules we need a middleware we need exception filters so this is how you can architect your backend application this is exciting project I'm going to share you all of these Concepts in this course let's create a new project in njs first of all you need to install ljs globally on your machine I'm going to install nestjs CLI this this command will help us to generate nests project my CLI has installed now we need to create a new project you can use this command Nest new the name of the project you can choose any name here I just use in fundamentals dpro I'm going to use npm now it is going to it's going to install all of these packages for me now my project has created successfully so I'm going to navigate to my project directory this is end fundamentals Das Pro now I'm going to open that into my code editor I'm going to use vs code so when you open the package.json file you can run your project in development mode by using this command npm start Dev npm Run start D you can see my project has started successfully uh by default njs uses 3000 Port you can verify that from the main. file I'm going to go to the Local Host call in 3000 let's see what will happen you can see Hello World so our project is running fine now in the app controller you will have a simple message the simple controller method it's a route get hello and you will see the hello world here hello world or you can say hello I'm learning nestjs I saved the application it has reloaded successfully let me send the request again you will see hello I'm learning njs so this is our source folder you will place all of your Source folder source code inside the source folder this is our main.ts file when you run this command npm run Start Da njs is going to call this bootstrap function and inside the bootstrap we have a factory function and we are initializing the app module this is our root module in here we have set the port we have the service we have module controller and the test file for a controller this is our module remember this is the angular structure and each module is consist each module consist of controllers services and providers you can import multiple modules here we have the service and uh you will place all of your spec file inside the test end to end test should be uh saved here and unit testing you unit testing files will be located here this is eslint RC rules for eslint prettier n if you want to customize the nest C nestjs project you will do inside the nest CLI we have package.json file we have TS config and TS config build this is used for typescript configurations let's talk about the concept of module in njs in njs each module is consist of providers controllers imports and exports so this is the building block of nestjs application you can read my notes I have provided you the PDF documentation nest in providers nestjs are classes that act as a Services factories or repositories if you have worked with angular you know the providers so you can encapsulate your business logic and it can be injected into controller or other services so controller serve as the function of handling HTTP request whenever you create a new endpoint you will register it inside the controller I'll teach you more about controllers in the next video Imports is an array specify the external modules needed for the current module you can import other module let's say you have break down your application e-commerce application into multiple modules you have post module you have products module you have ERS module you have users module let's say a user module can use the product module this is how you think in terms of modules if you want to export you can also export controllers and services from the current modules so each nestjs application will have a root module just like in angular root module serve as the entry point and is responsible for instantiating controllers providers and other core elements nextjs follow the module isolation principle ensuring that application is organized into distinct functional or feature based modules so you will have root module app module let me check the application you will have the app module you can see that you have Imports array this module has app controller and app service let's say we're going to build a back end of Spotify application we can divide our application into multiple modules you will have a root module and I'll have the artist which is feature module and we will have songs module to handle the songs functionality we have o module to handle authentication these three are all the feature modules SS modules are a functional organizational unit that follow the modularization principle it helps to do code free usability and separation of concerns principle under the hood they have implemented the principle design pattern to organize your code that's it let's create a new module I'm going to create a song module you can use CLI Nest G4 generate in the name of the module which is the module keyword I want to generate the SS module here you can provide any name I'm I'm interested in the songs module so you can see in the app. module it has added the entry automatically for you in the Imports array and you can see you have a songs module that's it so this songs module will have controllers providers and imports and exports array controllers are responsible for handling incoming request and sending response back to the client we are building the Spotify clone application let's imagine or let's say you want to fetch all the songs or you want to see all the songs of Martin gck artist your browser will send the find all songs request to the nestjs application inside the nestjs application you will have songs controller inside the songs controller you can see we have find all method the find all method will be called and this method will fetch the songs record from the database and send respon response back to the client similarly you can send the same request from your mobile application so controller will be responsible for handling request and sending response back to the client you can create a controller very easily all you need to do is controller decorator and inside The Decorator you can provide the prefix route prefix if you want to define the request Handler inside the controller you have to use the HTTP get decorator if you want to create the post endpoint you have to use the post decorator it's just returning a simple string message fetch all the songs and this method will be converted into this API endpoint Local Host callon 3000 / songs we are going to build these API endpoints to fetch all the songs to fetch a single song I created these routes to create a new song to update a song on the based on ID and delete a song on the based on ID I'm using the rest client extension to send the API calls it is similar to The Post men if you don't have rest client you can find from the vs code extensions and find the rest client the rest client package is saying You must have a file with HTTP I created the HTTP extension now my application is running at Port 3000 my development project is running at 30001 you should not aware you should not care about this project we are building project on Port 3000 if I send the request to fetch all the songs we don't have any rout yet it is giving me the warning message or error 44 you don't have all these end points I want you to accept the challenge and start building these end points we don't have any controller let's stop the application and I'm going to create a controller songs you can see that songs controller has created inside the songs folder we have spec file testing file and controller. TS file this is the controller decorator this is the prefix one more thing it has added the end entry in the controllers array now let's create the request Handler first of all I'm going to implement the get find all it is going to return a simple message find all songs let's restart or run the application you can see that our application is running now let's fetch all the songs I got find all the songs find all songs endpoint it means we successfully created the route to fetch all the songs now now I can send the request to fetch the songs watch all songs end point let's create a single song endp point you have to use the ID as a dynamic parameter I can say find one here I can say fetch song on the based on ID similarly we need update put for update I'm going to use the put HTTP verb update update song on the based on ID we also need delete I can get the delete from here let me replace the update to delete delete song on the based on ID and finally we need a post endpoint to create a new song I can say the post create create a new song so we created the CED API end points now it's time to send all the request it's working fine now create a new song endpoint update song on the based on ID delete song on the based on ID now you got the basic understanding of controller and how to create route in njs application let's talk about Services services are providers it means you can inject into another class it will be treated as a dependency we will have a service and the service is responsible for fetching data from the database and saving data to the database if you have to interact with database you have to write the source code inside the service you will create a method to interact with database we will use repositories don't worry and this service can be injected into controllers if you have multiple controllers into module you can inject the same service into that controller or multiple controllers you can also export the service from a current module and you can use that service into another module we will have the song service it's nothing more it's just a class and all you need to do is to injectable decorator it means you can inject as a dependency into another class this is how you will inject the service into controller or into a class you have to inject it in the Constructor it will be treated as a dependency for the songs controller now the songs controller is dependent on song controller is dependent on the song service let's create a new service I'm going to use n CLI to generate a service let's write the name which is songs it will create a class and it will inject into our songs module you can see that we have the song service spec file which is testing file and we have the surver we we have used the injectable decorator one more thing it has registered as a provider inside the songs module I told you services are provider providers could be factories helper function you will learn more about dependency injection in more details in the later mod so I told you service services are responsible to interact with database right now we are not going to interact with database we'll use the postris SQL postris database in the later videos for that here I'm going to create a local DB which it should be array local array saving saving record in the disk private read only songs array I'm going to create the empty array let's define a new method to create a new song and it is going to return let's push the song make sure you get the song from the create method there is a method push and I we need we need to provide a new song and let's create another method find all and and it is going to return a simple array this. songs and I can return this. songs array so we have created two method now it's time to inject this service into the controller I want you to do it accept the challenge and do it all right I'm going to do it for you song service now inside the create I can use the song service by using the this this do song service please create a new song I'm going to provide a dumy name Animals by Martin you can choose any name don't worry we will create a separate song model and separate interface for the song let's call the return and for the find all I am going to use this do song service. findall let's run the application our application is running let's send the API request to create a new song you can see I got a new song if you sent all the songs request I got all the songs let's save another song you can see I got five songs let's fetch all the songs I got all the songs so our service is working now in the real world application we will write the database code code here here save the song in the database and here what we will do fetch the songs from the DB but we will implement this feature in later videos in this video I'm going to teach you how to validate the request body when you send request to the Local Host call in 3000 3000 SL song we are trying to create a new song but let's say if I miss the title field it is going to give me the validation message the title should not be empty and title must be string let me REM know the artist now you can see title should not be empty and artist should not be empty so I would like to add this validation to our create new song API endpoint when you go to the Spotify if I click on any song this is the title of the song and this is the published date or release date and this is the duration so we're going to pick title duration and the date of the song let's do it this time I'm going to use class validator let's install the class validator package and we also need class Transformer you can see both packages have installed nexts provide validation pipe you can use validation pipe for specific controller method you can use it here or you can use it here it's your choice but but I'm going to create a global I'm going to register it as a global so I can use in any controller so you can call use method there is a method which is use Global pipes nexts already created the validation pipe you don't need to create it again I have imported the validation P from next sjs common package and now if you don't have dto which is data transfer object you have to specify the network data transfer object properties let's create a new song create a new file create song d. now we need to add decorator paste very adds let's create a new class and I'm going to name it to create song dto the first property is title I'm going to make it read only and we have the second property which is artist array and we have another property which is release dat or you can specify the type which is string and the type of part is it's an array and we have the DAT there is another property which is duration we need to store the duration in the time format now I'm going to use the decorator from class validator the type of title should be string and it's a required property so you can say it's not an empty we can follow the same stuff for artist not empty it's an array it's an array and you can say type string let's add decoration decorator for release date type should be string and class validator provides a decorator is date string now we have for if you want to store the time or add the validation for the time there is a there is a decorator which is military time and it's also required property so I'm going to add is not empty so is date string if you want to apply that you have to add the date in this format and you have to add the time in this format now we're going to apply we have already registered validation pipe here and we created the data transfer object which is create song dto now I would like to apply this create song dto in the create endpoint you can register it or you can apply it by using the body parameter please apply it on the request body and I can say create song create song dto the type is create song dto and this time I'm going to push create song dto let's try to test it out and we need to run the application so we have to send the request or add the Json body in the response let me open the rest c. HTTP file and we need to add the Chason body let's send the request you can see title should not be empty title must be string artist should not be empty and artist must be an array so validations have applied successfully I can say let's say lasting lover the title and we need the artists s let's now we're going to test it out so we have this record if you will add the date in different format you can see dat should be valid ISO 860 date string for date string format if I do in this way you will get the error dur must be valid representation of military time which is hours and minutes so it's working fine now let's talk about the middleware a middleware function runs before executing the route Handler inside the controller songs controller I have the find all route Handler and the create route Handler if you if you want to run any function before executing the route Handler you can write your code inside the middleware it's a function a browser wants to fetch the songs before fetching the songs would you like to call any method would you like to run your logic would you like to execute any type of code middleware can have request object response object and next function it means you can customize the request object if you want to add header if you want to log the request time you can do that a middleware can execute any type of code you can modify the request object if you want to add the request header authentication token to the request you can do in the middleware you can end the request and response cycle you can call the next middleware function by calling the next method we're going to build the logger middleware let's imagine you want to send request from your browser to server before executing the route Handler I would like to log the request message or the DAT time let's implement the logger middleware it's a class we're going to build a class based middleware and to create a middleware you need to implement the nextest middleware interface it provides a use method and use method will have the request response and the next function here I'm just logging the request dat time and at the end I'm also calling the next function it will if you will not call the next function it will not go to the next step one more thing middleware it's is like a dependency you can inject into module it will act as a dependency here we are injecting the middleware as a dependency to inject the middleware as a dependency we need to implement the nest module interface it will provide the configure method and the consumer will be middleware consumer and we just need to call the apply method from the consumer object and you need to provide the logger middleware here you need to specify where do you want to implement the logger middleware I would like to implement for songs API let's implement the locker middleware before creating a middleware I'm going to use Nest CLI please give me the help for nest generate command you can see that I got all the commands related to Nest generate you can generate class controller decorator filter guard middleware pipe provider we also have other options like no flat please do not create directory or no spec please do not create testing file let's create a new folder common I'm going to place all my middle Wares inside the common directory next generate Mi common SL middleware and the name of the middleware which is logger and I don't want a spec file please do not create the directory let's try with no flat and dash dash dry run let's see what will happen dry run it will not create the actual file but got the steps you will get the understanding how it will run it's working fine now no files return to dis but when you EX cute this code it will create the logger middleware file inside the middleware directory that looks good so I'm going to remove the dry run let's write the file perfect we have created the logger middleware you can see that it has already implemented the nest mid middleware interface and I got the use method with these three arguments request response and the next function here you can customize the request object if you want to add your custom logic you can do it here I can say request dot dot dot new date whatever you want to do do to dat string so we created the middleware now I told you or I taught you how to apply the middleware I want you to do it in the app modle we need to implement the nest module you can see that I got the configure method and we need to call consumer. apply the name of our middleware which is logger middleware and we have the four roots or routes I can say the songs now we need to test it out let's run the application my application is running now we need to send the API request if you will send the request to the root URL which is Local Host colum 3000 our middleware function will not run because we applied the logic to songs route fetch all the songs and I got the the log here request log send the post request I got the request log send the put request or send the delete request I got the log there are two other options to implement the or to apply logger middleware I can say option number one consumer. apply logger middleware for routes please run for only songs path and for only run request method. poost it could be option number two if you send request get request to fetch all the songs it will not run if you will send the post request for the songs I got the request if you send the put you will not see the request log another option we have let's do it consumer zor dot apply logger middleware for routes you just need to provide the controller it could be option number three it depends on what use case you like to use now I can fetch all the songs and I got the request log which create a new song I got the request log update a new song and I got the request log this is how you will create a middleware did you think about the error handling in njs if error comes from your application code nestjs provide builtin HTTP ex exception so let's say error comes while fetching the data from DB but we did we did not add any logic to handle the errors gracefully let's imagine we got the error while fetching the data from the DB error in DB while fetching record let's imagine that when error will happen nestjs will send this error to http exception this is the built-in exception in nestjs let me let me send the request to fetch all the songs you will see the server error with 500 status code next s has sent this message from HTTP exception but you can use the exception in your controller functions let's say I can say or did you think about how can you catch the errors you have to use the try catch block I can log a simple message I am in the catch block and this is my error let's try to fetch all the songs you can see that I got the error message I'm in the catch block and this is the error it means we successfully got caught the exception but we want to send the useful method in the useful status code in the response I can not see anything here for that we need to use the HTTP exception I can say through new HTTP exception it's a class and we need to provide the message can say server error or whatever you want to say I can say server error and we have to provide the status code HTTP status provides a lot of status codes you can use anything whatever you want to do for me server error internal server error if you want to send the message or cause which should be the error this one let's try to fetch all the songs you can see that I got the message server error with 500 status code which successfully caught the exception but if you want to use different error message you can do that you can use forbidden status code it will work let's restart the application now I got it so we have the status code 403 instead of 500 I'm going to replace forbidden to internal server error this is how you will cach the exception in your source code if error will come from this service this this method TR cach block will cat the eror got it let's talk about the pipes in njs there are two use cases to use the pipes the first one is to transform the value here in our example application we have the find one method we are expecting the ID as a input parameter by default it is going to give me the string so I can use the parse int pipe to transform the string value to number here you will see the type of ID it should be number another use case for pipes are to validate the input parameter in the create method we will accept the input argument like song title song artist we will validate the all the input arguments by using the validation pipe let's implement this transform value in our demo application so I'm going to remove it let's start it again it is giving me this response in nestjs you get you can get the dynamic parameter by using the ram decorator Ram decorator and the name of our argument which is ID I'm expecting the ID and I use the template string let's define the type of ID I'm going to send the request you can see the type of the ID is string we were expecting the number type but nestjs got us the string type you can convert this string into integer or the number by using the pipe Pars in pipe that's it let's send the request to fetch the song on the based on ID you can see I got the number ID number type if I provide the string value here you will get the validation error validation failed numeric string is expected bad request error if you want to customize the error message you can instantiate it eror status codee HTTP status dot not acceptable now I got not acceptable if I provide the numeric string I got the ID which is number type of the ID is number we successfully transformed the string value to number value in the next video we will implement the input validation using pipe we will create the custom validation pipe you have learned how to inject dependency by using the Constructor based dependency injection pattern we have injected the song service into the song controller what what will happen when songs controller will inject or instantiate the song service let me open that songs controller here we are injecting the dependency song service and we have provided as a dependency here this one this song service when Nest container instantiate the songs controller it first looks for any dependencies in our case we have the song service when it finds the song service dependency Nest will create the instance of the song service and cach it and it will return it if already created the cache then it will return from from the cache it will not create the new instance let's imagine you are using the song service inside the multiple controllers the first controller let's say we have the songs controller I'm using it first time here if I use song service inside the song service dos back file it would be treated as a second time now the second time it will not create any instance it will get the instance of the song service from the cache this is the Singleton pattern applied here next under the hood created a Singleton single instance of the song service and it is going to share the same same single instance throughout our songs module but you're going to learn multiple scope if you want to use the scop scope strategy if you want to instantiate a new instance after for after every incoming request you can use the scops but I'll talk about the scops later there are many techniques to use the providers some of them are standard providers value Prov providers known class based provider tokens class providers we use that class providers Factory providers used Factory providers and nonn service providers we're going to play around with all these six techniques let me explain with the help of examples this is the standard provider inside the S module we are using it as a standard provider but you can convert the above syntax into this one let's use it I need to open my project we need to create a new Branch model 3 lesson number one open the socks module so we are using the standard provider technique but you can write the above syntax or above code by using this syntax I can say this is provider just this it now we have the song service and the song service please use it as a class when you inject it into another class we are using inside the class in injecting as a dependency now you can test the application I'm going to send request to any URL let's create a new song artist must be stream this is this true why artist I think so I got the issue in the create song d I did add the H should be true I'm telling to class validator the elements of the array type should be string each element of the array should be string now it will it will be working fine if we have three articles or three artist Martin and John you can see that it's working fine now so we also tested this syntax this is the standard provider but if you like this syntax you can keep this syntax but I just want to show you I'm going to this out uncomment this one now I got the song service now I'm going to talk about the value providers if you want to create the moing service instead of the original service you can do that with the help of use value the use value syntax is useful for injecting a constant value or you want to put an external Library into Nest container or replacing a real implementation with more object we are using this one we are replacing a real implementation of song service with Mo object so when you need this use case you have to use the use value or if you want to inject a constant value you can use the use value or if you want to inject external Library into the nest container you can use the use value let's do it I'm going to create a mocking object here we have a find all method inside the song service when you open the song service you will see the find all method but we have to return the songs I'm not going to throw the arrow would be song service and use value which is songs moing object Mo song service that is it now now we need to test it I'm going to fetch all the songs and this time you are getting the response from the mo object not original song service so we have the find all method and it is returning this one if I will app add the artist I'm going to fetch all the songs from the mo service object mock service and you can see I got the record from the mock service instead of original song service find all method we have learned how to use the use value now if you want to inject the known class based provider you can do that let's say I want to inject an object with connection we have three properties connection string if you would like to inject any object object as a dependency you can do it well with use value I told you you can inject constant by using use value you can object an you can inject an object or you can inject the working object let's create a new file with connection. file and I'm going to specify some connection properties you have to create an new constant. file inside the common folder and I'm going to add the constants directory here you will have constant. TS file I can say connection. and I'm going to copy the code I just defined three variables and I have Define the type which is connection now I would like to register it as a provider you can register inside the songs module or you want to register it to app module it depends on you provide this is the name or the token value this is how I will inject in the class when I will inject in the class I'll use this token key use value let me provide which is connection so we have to inject it inside the song service I can use the add inject decorator so songs controller I think I injected inside the song service so I'm going to inject here inside the song service or let me inject in the Constructor function here I would like to inject I can say inject let's provide the key private connection here we need to provide the type I have defined the type this is the type so I can log the connection this. connection if you will not add the private so you can add directly without adding the this keyword I did not add the provider so I access the connection string without adding the this so let's say this is I can say I'm going to use the template string this is connection string when songs controller will be instantiated this Constructor function will be called so it will log this message you can see we have this is the connection string so I can get the connection string now I can see this is connection string and I can say the connection string or you can say my SQL dot dot col do dot 1 2 3 6 or maybe Port I created the fake or dummy connection stren you have learned how to inject the object as a provider and used it as a dependency now we're going to talk about class based provider we have already used the class based provider here this one not this one this one used Class so I'm going to create a new service this this will be called da config service inside the dep config service I'll have one property and a one function DB host and get DB host remember it's an injectable service so you can register it as a provider inside the app module by using the use class syntax and you have to provide the name of your service in our case we have the da config service and and then and then I can use the dev config service inside the app service so I can create a providers hold up let's rename providers let's create a new class def config service.ts and we have these properties we have TB host in the get TB host so let me register inside the app module we have provider and I can say please provide Dev config service in the use class Dev confli service and and now I can inject inside the app module let me inject it here I can say private Dev config service and I can say def config service and I can call the method from the D config let me convert into the template string da config service. DB host so we have to send the request to the root URL to test it rest let me send the request hello I'm learning NS fundamental and this is the DB host which is St config which is Local Host DB host so if you want to inject the known service provider like a simple object and you want to inject Dynamic value you have added the check or if condition if node development equals to development then you you have to inject the dev config otherwise you have to inject the pro config if if you have two objects and you want to inject on the based on condition this is the known service provider it means these will not be classes if you have this type of use case you can inject by using the use Factory so I'm going to call inside the app module let me let me show the demo I just created the two object and in the provider we have used the key which is config and I use the used Factory and we have to provide the arrow function it's just returning a value Dev config and the pro config if you want to in inject dependency or inject provider only based on condition then you can use the US Factory and now the same way you can inject config value in the app service here we have to inject it by using the inject decorator provide the key which is config in private config we have Port value and type a string and you can say Port should be this do config do Port so we have to test it to send request to the root URL now I got the host which is Local Host and the port which is 400 so we have to add 4,000 you have learned how to inject provider as in the standard way you have learned the use value you have learned how to add non class based provider you have learned how to use use class provider how to use the dynamic how to in how to register the dynamic provider and finally you have learned how to how to register known service providers the previous video you have learned multiple techniques to register a providers when you register a provider by default nestjs use this scope default it means a single instance will be created which is called the Singleton pattern and this single instance of the provider is is shared across the entire application nextest cach the instance when application request for the second time it will not create a new instance second time it will return from the cash another injection scope technique which is request a new instance of the provider is created exclusively for each incoming request and we have the third technique injection scope technique transient providers are not shared across consumer each consumer that inject a transer provider will provide a new dedicated instance most of the time you need default scope because single turn instance is recommended to improve the performance of your application when you get the instance from the C it will give you the instance in the more faster way instead of creating the complete object it just give you the copy of the already created object so you can play around with injection Scopes let's say if you want to use it inside the song service I didn't I could not find how to debug the dependency injection so you have to use here scope injection scope what we have to say scope scope to transient the performance of your application will be hard it will decrease the performance but but it depends on your use case what are your requirements similarly when every incoming request if you have use case you want to create a new instance you can use it well for the requesting purpose for testing purpose I'm going to open the songs controller and here we have to say it's an object let's import this scope I'm going to send the API request it's working fine one thing you did not notice when I will create a new song it should add the song in the array so I have created three objects three songs object in the songs array when I will send the request to fetch a single song or all songs it should give me the empty response because on every request it will delete it the complete data complete songs because it will also re instantiate the song service inside the song service we we have the are we have the songs are you can see I created the song now when I try to fix all the songs it should give me the first song or all songs you can see the empty response in this video I'm going to teach you how to add one to many or many to one relationship between two entities where a contains multiple instances of B entity and B entity contains only one instance of a entity we have two use cases we are building this Spotify clone if you are using or you use Spotify each user has its own playlist and each playlist can have multiple songs so you as a user can store multiple songs or save multiple songs in the playlist so there is a one to one one to many relationship between playlist entity and the songs entity see similarly we have each user can have multiple playlist many playlist can belong to a single user so this is also a many to one relationship between playlist and the users let's create the playlist entity and add relationship we don't have any playlist entity go ahead and create a playlist entity I have created a new folder playlist. entity. TS file so I'm going to copy couple of the code from my notes we have created the playlist entity now we have to make make a relationship between songs and the users similarly type orm provides one to many decorator and this represents the target entity relation entity we are making a relationship with song entity this representing the inverse side of the relation in the song model we have a playlist property and we have the array of the songs I'm going to copy this code and I'm going to paste it here we don't have song. playlist open the song entity here we can add a relationship but we also going to add a relationship between user so I'm going to copy this code and paste it here now we have to add many to one relationship in the song entity so many songs can belong to a playlist for each unique user we have to import the playlist import many to one relation and finally we have to add one to many relation in inside the song inside the users user entity so I'm going to copy that code inside the user model and I'm going to paste it here now everything is fine now I have added many to one relation in the song it means it will have the primary key of the playlist entity and save it as a reference key or the foreign key now we need to create the clip playlist module I also want to create a new playlist I'm going to create a new endpoint but first of but first we need to register our new entity I'm saying to type orm please convert or make relation between playlist and the user playlist and the song every everything is fine now when you go to the pg admin refresh your tables you will see playlist table this is the playlist table and we have the user ID when you open playlist entity we have added the many to one relation it means it will have the user ID as a foreign key and inside this song entity we have added many to one relationship as for the playlist so this song will have the primary key as a foreign key of the playlist entity let me show you inside these songs we have a playlist ID relations have created successfully we created one to many and many to one now I want to show you how can you save a record with relation entities go ahead and create a playlist module you can use with n CLI to create a playlist module but I'm going to use my not notes playlists module. and I'm going to paste my playlist module we don't have playlist service and we don't have playlist controller I can create these two files controller. let's create playlist dot service. file I'm going to copy my playlist service we have to import couple of tip dependencies inject dependency and we need playlist we need a user we we need a song that is good right now also need to get the injectable we also need to import report osit Tre I don't have any user so import the user we have service right now and we going to create controller or we can build create playlist function I'm going to create a new method you can see that we don't have create playlist dto we are just creating the instance of playlist I'm providing the name of the playlist when you go to the playlist entity you have the name property each playlist can have multiple songs so I will get IDs of the songs from the request body we are using the same logic in the previous video we used here I'm setting the relation with songs entity I am creating the playlist when you are when you need to create a playlist you have to provide the name and you can set the relation for the songs and you can set the relationship for the user when we will implement the authentication I will not find the user directly from the database I'll get it from the logged in user we have set the relationship with user and finally we are saving the playlist we don't have create playlist D go ahead and create a playlist D we have used that logic I'm going to create a new file playlist dot or you can say it should be new folder dto inside the dto playlist create playlist dto create playlist do D.S we are expecting the name type should be string and I'm getting the IDS of the song from the request body that's why I specified the number type the array of the numbers and we have the user it should be a number it should be the ID and finally we have to use the create playlist dto we have to import it and now we have to build our controller function and the endpoint do we have a controller yes we have a controller everything is good to go I've have specified the playlist with this endpoint we injected the playlist service we have used that logic and I'm returning a simple playlist in the response we have to register the playlist module inside the app module and it will also be treated as a feature module just like we did with songs module we have playlist module now I have to test the application you can test it by sending the request do we have a user I already created the user in the previous video I can double check check it my users you can see that we have three users I would like to save the record for the second user with ID number two rest client we have to create a new playlist I can say create new playlist we have to send the post request Local Host column 3000 playlists content type is equals to Json application Json let's provide the data I'm going to create a new playlist with Feelgood now I would like to save the song with ID number six do we have the song with ID number six let me double check it yes we have the song with ID number six and this is our user let's say I'm going to say I'm going to create with user ID number two it's not a valid request now it looks fine we need to add a space here we have a playlist feel good now and we have a one song with ID number six and we have this user so this user has playlist feel good now and it has only one song you can double check it from the playlist this is the playlist record in this video I'm going to teach you how to connect nestjs application with type orm and post nestjs provide multiple drivers to connect with database if you want to use mongod DB you can also do that if you want to use my if you want to use post you can do that in this video I'm going to implement the post with nestjs uh typ orm is a object relational mapper you will write the code in JavaScript objects and these objects or classes will be converted into database tables if you want to write SQL queries you don't need to write plain SQL cury you can write queries in the form of objects first of all you have to install a couple of dependencies we need nestjs typ orm package and post driver and type orm uh open the package tojson file and you have to install these dependencies I'm going to add them here let me install all of these dependencies we also need typing for nestjs we have to install this package I'm going to install as a def dependency we already have this package types at node we installed these packages njs type orm post and type orm so now we need to import the type orm module into our root module in our case root module is our app module so we have to call this method from type or a module and you have to provide the connection strings or connection properties like type host Port username password database entities and synchronize whenever you will create a new entity you have to register it here for synchronize means whenever I will run the application please delete the data from all the all the tables synchronize please delete everything from the table but do not use synchronize in production otherwise you will lose the production data whenever you have to create a new entity you have to add it here inside the entities array so the for root method Sports all the configuration properties exposed by the data source Constructor from the type or a package I have installed PG admin if you don't have you can install the post admin I'm using PG admin 4 you have to provide your password let's connect with server we have to create a new database right now I'm going to create a new database Spotify clone this is my user go to the app module and we have to import the type type or module here we have have to install manually it's not giving me suggestion from Nest JS type orm and we need to get type omm module so I'm going to call a method type orm module do for root with we have to provide the options database which is Spotify clone host which should be Local Host and we need to specify the port for post gr I think 4 5432 by default username for me it's postcript add you have to provide your password for me I think it's root I specified the database name and we have empty entities right now I don't have any entity and synchronize set to true it will create the database tables po it should be usern name not a user so how can you verify we have successfully connected to type orm you can use data source object in the app module now you can inject it and I can log let's add private you can log anything from DB name let's say and I can get it from the data source dot data source. database this do I have that property let me check it dat source. driver dot database Let's test it out I'm getting the error wrong driver so I think I did not provide the type let's add the type the type of the driver which is post now we have made the connection successfully you can see DB name which is Spotify clone you can also check the songs table inside the Spotify Let me refresh it and I would like to look at the tables we have the tables I don't have any song because we did not create any entity right now but we have successfully connected to the postris database in this lesson I'm going to teach you how to create an entity entity is a class that maps to database table or collection when us using mongodb you can create entity by defining a new class and Mark it with an entity metadata and inside the metadata you can provide the name of the table in our case I'm going to provide the songs table name an ID which is the primary generated column the ID will be generated automatically it's an auto increment and we have the title I use the column decorator for artist array postris also Sports error data type you have to provide the column and I'm using the V character you have to say this column is an array type you have to specify the array should be true and we have a release dat property or release dat field in the database table I'm specifying the call colum decorator and we have and we are seeing this the type of this field which is State we also have time type in the post you can say we have the duration I specified the date data type in the post Cas you can Define the time I don't want to save extra date field here I only need Time Properties time related metadata and lyrics lyrics could be the long text that that's why Post sports text type if you want a long if you want to store a string with long content or long long length entity songs which is the name of the table and you can say I spec I have I I have specified the description for each field when you will create the entity you also need to update the lyrics in the create song datto we did not we did not add lyrics property in the previous videos that's why I use the lyrics it's an optional property it depends on the user does user want to add lyrics or not and finally we need to register the entity to the app module and then you can can test the application let's try to implement it go ahead and create an entity I can say songs or song. entity songs. entity or song whatever you want to call let me say what I called song. entity dots let's specify the class I can say song I can provide the entity the name of the table which is songs now we need primary generated column ID the type should be number and we have the title field let's specify the title column title type should be string and we have another column this time we have the artist array you have to specify it as a string array here I I can say the V character V character and the type should be aray and we have release date duration release date let's it should be date release date type should be date and we have duration type should be time duration and the date and finally we have the lyrics type should be text lyrics type should be string now we need to test this entity you have to add register the entity in the song in the entities array now it should create the songs table for us let me test it out from the PG admin refresh the tables I got the songs table with these columns ID title artist release date and the duration we don't have any record so let's update the create song dto and I'm going to copy it and I'm going to paste it here create song dto let's add another field the optional which is lyrics everything is fine now we have tested it in the next video you are going to learn how to perform C operation we're going to fill these methods update delete find one find all and the create this time we going to fetch and save data to the database let's perform cred operations type orm Sports repository pattern for each entity type orm provides repository and this repository has CR features like create create record update record find record and delete record repository provides the method first of all you have to register the type or a module as a feature into the songs module we providing the entity like these entities I would like to use inside the songs module and it it will provide the repository songs repository here then you can inject the songs repository to use songs repository you need to import the type or a module into songs module just like we did it here this this module uses the four feature method to Define which repositories are registered in the current scope we only need song entity that's why we use the we have imported or added the song entity now we can inject the songs repository into the song service just like we did we did it as a dependency injection please inject the song's repository and the type of the entity which is song and you can in you can import repository from nestjs type or M package now I told you songs repository provides scrud method to create delete update here you can look at that create delete fetch records from the songs table let's implement this create song method this time we don't need to add a record in the local DB you're going to save the new song by using the song repository. save method let's Implement here in the songs module we have to import type orm module as a feature provide the song entity I would like to use this entity into the songs model in songs module now you you are able to inject songs repository into the song service so I want you to inject this songs repository Constructor pattern songs Repository repository and I can provide the song type which is entity now you have the exess of crud methods so song repository provides this safe method just like you learned here it provides this safe method for first of all we have to create a new song and it should return a promise with song so I just created should say create song dto the type should be create Song D so I just created the instance from a song class I specified the title I got the title from D I got the artist from dto duration lyrics and release date from the dto and finally you can call Safe method this. songs repository and I will would like to call this safe method and provide a newly created song and it should return the object get rid of the songs array I don't want to use it we also need to remove everything from here now it's time to test this G method make sure you have called yeah it should use the up expression here in the controller let's look at issue here it should promise and the song inject the repository inject repository and we we have to provide the entity which is song so everything is fine you can test without a sync V by default it should return the promise HTTP let's create a new song we also need lyrics I'm going to send the request amazing we have a song you can verify from the database you can see that that I got the first record this is the lyrics duration and the release date now it's time to implement find all it's easy to implement the find all all you need to do is provide the return type promise with song array return this do songs repository do find that's all you need and in the controller songs controller you can also add promise with song aray let's fetch all the songs from the DB I got the array right now we have only one record now we need to implement the find one find by ID you can create a new method inside the song service and it is taking the ID as a parameter and returning the promise with song you can use song repository. point1 method and in the controller we need we need to pass the ID as a integer and return the song in the response let me open the songs controller we already did it I'm getting the ID all you need to do is return this. song. find1 here I can say promise with song Let's test it out by sending the request only the based on ID you can see I got the first record if I try to fetch the second record I don't have any record that's why I got the empty let's implement the remove method I'm going to create a new method inside the song service it's just returning nothing or you can say delete result you can use that and return here and we need to use this method into the songs control ER we have to call it this Do song service. remot and we have to provide the ID we did not pass the ID or get the ID as a Prem I'm going to use Prem decorator and get it here ID and it's returning promise with delayed result we need to test it out first of all let's create a new song to we have a song lasting lever two the ID of the song which is two now you can perform the delete operation I would like to delete this record so I got the delete result we have successfully deleted if I try to fetch all the songs no I think I deleted with ID number one so first record has deleted and we need to use the update let's perform the update record so we need update method I'm going to create a new method inside the song service we don't have update DTU data transfer object you need a tip you need a new data transfer object for update the record because when you update the record all the fields are optional but I can get update result from type orm we don't have update song dto we have to create it I'm going to create in the dto update song Das d. so this time we have to copy everything all the fields are optional all I did I copied the create Song D and put the optional for every title for every field is title should be optional so I can say instead of empty it should be optional it should also cre it here is optional is optional now it looks good so we have to use the updates s video now we need to implement the controller function songs. controller that we need to get the Prem and we need to get the body need to get the pram and update song dto and I'm going to call this do song service. update the first one is ID and the second argument is update song tto you have to import it the return type should be promise with update result that's it I have found the issue which is this space content type let's try to send the update request duration must be valid presentation now it looks good so you can double check it from the database this is the record with id2 we have successfully updated the record we have tested the application in the next next lesson you will learn how how to implement the pagination now we're going to implement the pagination I'm going to use external package to implement pagination in nestjs uh first of all you have to install this package I'm going to register it here and we have to install it and now I'm going to add a new method inside the song service this time I'm going to call it paginate and I'll use paginate method from nestjs type or M paginate and it will accept the pagination options like page metadata when you will fetch the record on the pation it should give me the items array and we have this metadata total items item count items per page total pages and current page these are all the options inside the options object and finally it will return the pation and we have to provide our model which is song and we have to call the page unit with song entity we have to provide the songs repository and the options if you need to add a cury builder like filtering or sorting you can also do that but here is our control rer function we use the Prem now we're going to use security decorator and it should name of the field which is Page you can add a by default default value which is one and I applied the pars int and I have added the default value and we have another field or another property and I'm getting it from the cury prams this is the limit and default limit which is 10 and I applyed the pars into pipe operator and finally it should return the pagination with song entity if limit is greater than 100 please do it 100 otherwise we have to specify the limit or tell or add the limit there is a page unit method we created inside the song service and you have to provide the page and the limit we're getting the page and limit from the cury so you have to test it by sending the cury parameter page which is two and the limit whiches to I want to see two records per page and I want to see the page number two if you want to add the Sorting you can also do that by using the query Builder please apply sorting on release date I want to see the latest song on the based on date let's implement it or you can Implement by your own first step we have to create a new method paginate and we need these options I can import all of these from the method so we have the pagate method now we have to call it inside the songs controller you can it depends on your use case but I I'm going to call the paginate method in the find all so I'm going to replace my find all method to this find all we also need cury Prem it's just getting the es lint warning messages we also need default value pipe we need pagination from nestjs that looks good we can test it this time I'm going to send the request to fetch all the songs it has applied the limit 10 and default value which is page which is one over the first page total items item count items per page 10 and total Pages we have one and current page which is one let's add another record new song to let's add another record new song 3 let's add another record new song four now we have four songs you can say I want to see the page number one this time I want to set the limit to two I want to see only two records per page we have the items array you can see we have only two records there are total two pages we are on the first page and items per page two item count two total items we have the four I told you if you want to add sorting you can also do that by using the query Builder inside the song service I'm going to add curil fer here and we have to provide cury Builder not songs repository we have to fix it cury Builder let's provide the cury Builder please create a new song with let's say a new Five song latest date it should should give this record first let's create it created a new song I got a latest song Only the based on release date it means it's working fine now in this video I'm going to teach you how to build one toone relationship between two models one to one relation where a entity contains only one instance of B and B contains only one instance of a let's take an example a user can become an artist or an artist can have only single user profile so there is a one toone relationship between user and the artist we don't have an artist model or artist entity first of all you got to create artist entity with primary key and then you have to create the user entity because we're going to make one to one relationship between artist and the user I'm going to have ID field or First Column first name column last name column email column and the password column for user entity now we're going to add one to one relationship type or provides one to one decorator to add relationship between two two entities uh in the first argument you specify the relation type I'm telling type orm I would like to make a relationship with with user enti this is the type of the relation you specify the relation entity type by following this syntax AR function and this join column will rep will create the reference key or a foreign key of the user entity inside the artist entity so we have so we will have a user ID as a foreign key inside the artist and finally you have to register the user and artist entity in the app module now we're going to implement these steps let's create the first a new Branch so I'm going to create a new artist entity if you like you can use CLI command to generate a new entity so I'm going to say artist do entity. file I'm going to copy my code there is nothing here you already learned how to create an entity and next we have to create a user model a user entity go ahead and create a new folder with user or users let's keep it to artist so I'm going to create a new entity user. entity. P the code we have ID field first name last name email and the password and now we're going to make a one to one relationship I would like to store the user ID inside the artist model if you want to store artist ID inside the user you can also do that it depends on your use case like I want to make a relationship here let me do it here we need one to one decorator specify the type of relationship by following the syntax we would like to make a relationship with user and here we will have the user and the user and I also need a join column that's it for now cannot find a module user. .ts file so we have to import it manually now it looks good and now we have to register these entities inside the app module we created couple of new entities please convert these entities into tables I can say artist and we have user our last step is to test the application and I have to run my PG admin let me connect with post this database so it has successfully let me check my schema which is 45 clone I have to connect it inside the tables we have the artist and the users table we have have the user ID inside the artist and inside the users we have for columns or ID first name last name email and the password our application is running fine now this is how you will make one toone relationship between two entities now we're going to talk about how to implement many to many relationship ship many to many relationship is a relation where a contains multiple instances of B entity and B entity contains multiple instances of a let's take an example many artists can publish many songs and multiple artist can belong to one song or multiple artist can publish multiple songs we have a multiple many to many relationship inside the artist nestjs or type orm provides many to many decorator this will specify the target relation entity and this is the inverse side of the relationship and it will have the songs array and on the song we will have the artist array we have a many to many decorator the target entity in the song we have Target entity which is artist and the second argument specify the inverse side of the relationship inside the artist we have songs property that's why I can access the artist. songs and inside the artist entity we have song. artist that's why I can access the artist from this song entity song. artist that is the inverse side of the relation when you set the casc to true it means you can create or update the record while creating a new song or an artist I'll teach you the benefits of ask getting when you implement the many to many relationship you you need a joint table many to many imple uh relationship always work with third table which should be joint table and I rename it to songs artist and this songs artist will have primary key of the song and the primary key of the Artist as a foreign key and we also need to refactor some create song dto instead of using EST string EST string we going to we are going to get IDs from the request parameter IDs of the artist and IDs of the artist in the update song video and then you have to register the artist entity in the songs module that's because I want to the artist repository inside the songs modle and finally you need to refactor the create method we're going to get artist here the first step we are going to get this artist IDs from the request object or request parameter or the request body and then we will find all the artist only based on IDs and finally here we are going to set the song do artist equals to artist if you have set the casket to true just like we have done it done it here cascading we set to true now it will set the relationship between songs and the artist it will automatically create the record with third table which is the joint table here here it will create a record it create records in the songs artist table by by setting the relation with this one songs. song do artist should be artist and finally we're going to save the song in the using song repository and you can test the application now um let's implement it first so we have many to many relationship I'm going to add this relationship in inser the artist I'm going to do it here this specify the target relation type and we don't have we we did not create the song. artist inside the song entity now we have the songs array let's import many to many I'm also going to implement it here many to many decorator the target entity in our case it's an artist and it's going to take the artist let's specify the inverse side of the relation artist dot songs and we will have join table I'm going to name it to songs artist or artist song let's take it the songs artist and finally I'm going to specify the artist array duplicate identify yeah I don't need this type because I'm not getting the string array from the artist instead of I'm getting the array of the artist from the request parameter we added many to many relationship inside the song model or song entity and we forgot to set the cascading to True here you can do it inside here G SC to true now we need to refactor the create song dto I have to refactor from it should be number and the first argument is an empty and and it looks good similarly we have to refactor the update song dtoo it should be number array of numbers the first argument is empty looks good now we need to register the artist entity inside the songs module so we can access the artist repository inside the song service I I'm saying to type orm I would like to access the artist repository inside the songs module or the song service that's why I have to register it here and finally we need to refactor create song I can say create uh inside the song service so you can do it too if you want here we have to find all the artists on The based on ID then we have to set the relation with artist and songs so you can do it but first of all we have to inject the Repository which is artist I can say private artist repository and repository I can say artist let's get all the artist you have to add a Sync here this do song artist repository find by IDs I can use that method provide the artist ID from the song dto artist now I can set the relation with song. artist it should be artist so we have set the cascading it will create a relation many to many relation with songs and the artist now it's time to test our application rest client here we have to send the post instead of artist we need to send the IDS of the artist a user can become the artist so we don't have any record in the artist and the user model you have to create it manually so I'm going to refresh you can see we have the third table which is songs artsts is not artist we have to fix it inside this inside the songs entity here we have to fix it this I'm going to refresh the table get it off this table you can drop it delete or drop yes now we have song artist with song ID as a foreign key of the song model artist ID we don't have any user right now I want you to create it manually let me do that I'm going to add a new record with ID one it should be Jane or saga Saga gmail.com I'm going to add anything here pass password let's add another user I can say Jane and I can say do Jan at gmail.com password 1 2 3 4 5 now you can save the record so we have two users right now if you want you can also add another user or artist I can say Martin gar Martin at gmail.com 1 2 3 4 5 let me save the record so these two users are the artists but we need to make a relation inside the artist table let's add a new record with ID and here we have to add a artist ID let me double check it yes one and the three one we have to add another artist one the ID should be three so these two are the artist ID should be here we have to set the ID should be two now it looks good so what I'm saying that a user with ID3 is an artist a user with ID one is also an artist so one Martin and seag are an artist and Jane is a just a simple user so when you create a new record I can say let's add a new song so these two are all the artist they are going to create they have created a new song I can say you for me that is it right now I'm going to send the request sounds good we have a new record title this is the artist ID this is the complete artist so we have an art ID one and we have the relationship let me double check it from the artist and the songs it just created a single record it did not get the ID 1 and three I don't know what is wrong with it let's do it here one and three you for me to again I am getting the ID only one let's log the song d. artist 1 and three then what why 1 and three it looks good maybe the issue with here console.log so when you look at the artist record oh we have one and the two so one and the two instead of 1 and three let's provide the two you and for me three now I got the artist ID one and the two it will also addit a relationship here inside the songs and the artist I'm going to find now you can see that a song ID with 10 has two artist these two users user ID number three and user ID number one in this video you're going to learn how to implement this signup functionality a user can create an account in our application and we need to save the user in the database first of all we have to install dependencies I'm going to use bcrypt JS password bcrypt JS package to save the user password in encrypted format I don't want to save the password in plain text like 1 2 3 4 5 we have to save the password in encrypted format that's why you have to install this dependencies let me open my package.json file I'm going to add a new entry let me copy it and I'm going to paste paste it here we also needed to install the typing for typescript I have to add the typing in the dep dependency I'm going to put it here so I'm going to run npm install please install dependencies for me you can see two packages have installed added new two packages now we have to create a user module and the Au module we don't have a user module and Au module inside our application I'm going to use nest CLI to generate a new module I can say o we have created a new o module you can see that we also need to generate the ser service for art you can see that Au service has generated we also need controller I can say AU an au controller has created it has also added the entry inside the controller's part we have it has automatically imported Au module inside my app module here is the O module now we have to create the users module one more thing we did not export the odd service yet here I I can say I would like to export the Au service it means whenever you will import the Au module into another module like we have imported the Au module into app module it means I can inject the OD service inside the app module that is why I exported the OD service let's create the user module I'm going to create manually users. module. TS I paste it we don't have user service yet we have to create the user service let's use the nli a user service has created we have to import the users module inside the app module so we have the user service and we have the user module I've also added the type or a module and registered the user entity because I would like to use the users repository inside my users module I would like to inject the user users repository into the user service now we have to register a new route inside the O controller we're going to register the signup and the login route inside the O controller we don't have a user dto yet but we do not we also don't have a user service do create method I want you to create the user D you first I can say I would like to add my DS inside the dto folder create user. dto file I'm going to paste my code we are expecting the first name last name email and the password from Network request this is the network data request object now we got to create the create function inside the user service it is saving the user inside the database do we have a user entity now we got to do it inside the user service here we have to add the logic we need to inject the user repository I've already told you how can you do it I have created the create method what this create method is doing remember we have installed bcrypt JS package let's import it first I don't want to copy the code inside the Constructor function now it looks good we have to import it first create BPT package here we are just injecting the user repository we are generating Assa it is nothing more it's just a number we need a salt to encrypt the user password there is a hash method inside the bcrypt library and we are using this hash method it is going to return the promise first you first argument would be PL text password we are getting the plain text password from the network request and this is our salt and finally we are just saving the user depository user inside the repository and we are deleting the password it's an extra remove them I don't want to send the user password in the response that's why I have deleted deleted the user password and finally we are returning the user from the response in the in the response we have called the user service. create method here now it's time to test the application one more thing we have to refactor a little bit our users entity I'm going to make it to Unique should be true because because email should be unique for each user and I don't want to save the pass I I don't want to send the password in the in the response it is saying that when working with type orm there might be cases where you want to exclude one or multiple columns field from being selected that's why we have used the exlode now let's run our application and we have to save the user we're going to send this request HTTP we have to send request to this route because we created this odd /up route we have to provide first name last name email and the password now we're going to test it out I have caught the error if user service is a provider if user service is a provider it is is it the part of au module you should learn from the error inside the Au module we have to import the user module because I am using the user service inside my o controller or inside the a service let say user module here we are injecting the user service inside the O controller everything is good to go right now we have to test our application what I would like to send the signup request let's create a new account I got the error 500 internal error duplicate key value Violet unique key do we have a user inside our database can say John one two still we are getting the same value same error cury failed error duplicate Cube value viate constraint we have changed a data entity and the table we have to we have changed the database Act I have added two new entries unique constraint and the exclude so we need to drop our schema and let me do it I cannot drop we did not use migrations at the end of this module I'll show you how to use the migration whenever you need to update a database you have to create a new migration what I want to do I want to disconnect from the database Spotify clone now I would like to delete it is used by some other let's use another database I can say one I found this is the shortcut to handle this error because we did not use migration so I can say that now I got the data from scratch where application is running fine now let's sign up you can see that it has resolved the issue the issue was with database update I got a user when you go to the Spotify clone one get rid of this one Spotify clone one and we have to go to the tables inside the users we have a de cord email john1 12@gmail.com and this is the password in encrypted format in this lesson you are going to learn how to perform login request when user sent the login request we have to verify the user from our database we have to decrypt the user password and compare the user password we're going to implement Json web token authentication a user provides the credential like username and password to the server then our server will generate the Json web token and send back to the user it will have the header payload and signature don't worry I'll teach you everything when client reive the Json web token if you are building front-end web application you can save the Json web token in the local storage when user want to receive or user wants to receive protected rout he must need to provide JWT token in the request header and server will receive the JWT to token from the request header and it will verify or validate the token if token validated successfully it will allow you to access the protected route you will learn how we are going to implement Json web token authentication we're going to use passport passport strategy or passwort package you have to install these two packages I'm going to install it in my dependencies we have to run npm let me hold on we did not create a separate Branch module number six lesson number two now we have it npm install we have installed two packages the next step we have to create a login route I can create inside my o controller let's create a new login route we don't have a login D yet we also don't have a login function inside the OD service yet let's create a login function inside the OD service au. service here we have to create the log function and we also need to get user service as a dependency let's create a new method first of all we are trying to find the user on the based on email if user found it should give me this user let's complete this step first we have to find the user we did not create the find one method I can say that inside the user service let's create a find one method it is going to take the partial as a user and we're getting the email or we can let's try to use the login dto login dto if it did not find the user it should return the unauthorized access we have to find the user only based on email we don't have login dto let's create a login dto inside the AU dtos I can create login. D.S file so we have the login dto I got the email we also need to import login dto we also need to import user entity and it should return the user that's it now the second step is we have to compare the user password inside the OD service the second step we have to compare the user password I have to import the bcrypt import Star as bcrypt from bcrypt now I can compare the password with plain text password and user encrypted password if password matched then we have to return the user and delete the user password if password did not match we have to send unauthorized exception that is it right now we did not inject private Au service now I have called the dto login method and provided the login dto let's try to send the login request rest client. HTTP we have created a user with John 12 John 12 run the application let's send the API request to login user it should be 3,000 not a 3,000 one we successfully got the user back in the response let's say I'm going to provide the invalid email I got error cannot find user if I provide the invalid password I got password did not match and unauthorized it's working fine now but our goal is to send the Json web token when user made successfully login request it should send the Json web token in the response in the next lesson I'll teach you how to create Json web token and how to send the Json web token in the response we have found the user on the based on email and we have encrypted the user password if user has logged in successfully we need to send the Json web token and when you will apply authentication on protected route you have to send the Json web token in the header we're going to use nestjs JWT package and passport JWT package and then we will import Port jwd module you have to provide a unique key you have learned how to create the login function and we you have to refactor it right now you have to send the access token you can create Json web token by using JWT service this is the provider you can inject it here as a service provider then I will move my constants into a separate file au. constants does and you have to register the JWT module and update o constant Secrets I also updated the expiry date of Json web token it will be expired after 1 day we going to have JWT service we are extending it from the passport strategy remember I'm using the nestjs passport package and we have passport jwd strategy here it is just extracting the token from the header we are checking the Json web token expiry date or expiry validation or expire duration here you have to provide your secret key which we have saved and then finally we're going to have validate method it is returning the user ID and the email when you apply the oard oard JWT oard will call this validate function you have to register the JWT as a provider then this is how you will Implement authentication you got to create a guard it's like a middleware in expressjs if you want to implement role based authentication you need guards we have jwd odard it is extending oard from the passport if you want to add your own custom logic you can do it here this is how you will make your route protected by using the gwd O card and finally you have to apply you have to send the authentication request like first of all you got a login login route will give you the Json web token then you can access your protected route like this is the protected route profile is the protected route only authenticated user can access this profile route so you have to provide the validation token which is this one Json web token in the authorization barrier it's a scheme and it will allow you to access the route so let's implement it first first of all we have to install a couple of dependencies here passport JWT nestjs JWT and passport JWT strategy I also need dep dependency which is typing of typescript let's do it here and we have to install the dependencies these packages have installed now you are able to use JWT module let's use inside the app module we have to register it we will move this constant into separate file but right now I'm going to do it in this way JWT module. register and this is the secret key and finally we have to refactor our OD service if everything is fine then we can use Au or JWT service you have to add this return type return type if password mashed generate adjacent web token or create a pad object I'm going to create a payload object now we are just adding email and the user ID inside the payload and it is generating the Json web token let's create a separate file for the constants can say o/c constants do let me refactor it here one more thing you got to register the JWT module in the Au module instead of app module that was a mistake so this is our authentication module we have to register it here out constants do Secret and you have to provide sign in options options we have expiry date which is one day so we have registered the jwd module now you have to create jwd strategy I can say JWT strategy dos it's nothing more it's a service or provider you can inject it injectable export class JWT strategy passport strategy it is going to provide the strategy passport JWT now we have to call Super Constructor and you can extract the header from Au header as a barrier token and we have to provide the ignore expiration check the expiry date secret which is our secret key ke and we will have the validate function whenever you apply at the O card this validate method will be called our next step is to register GWT strategy in the O module I have to register it here JWT strategy now you have to create the guard which is JWT guard dos export class JWT guard it is also a class or service provider that's why I I'm using the injectable and we have to extend it from the passport from the odard which is from the the njs passport package make sure you say this is the JWT if you want to extend this JWT guard you can do this our final step is to apply the O card to the public public route let's say I want to protect this route I did not create it yet let's say get profile and it is going to take request return request. user should be decorator now we have to let's do it without card npm Run start f our application is running now let's send the login request you will receive the access token I'm going to copy it and I going to paste it here access token now let's access the profile slash profile because we created the profile route in app controller I'm going to send the request cannot access the profile I do not add the route I can access the profile route I got the 200 status code it means route is working fine if I apply the authentication guard I can say use roles or use roles use guards yep I can mention my guard which is or guard if you have what in Express JS it's nothing more it's like a middleware this oard function will run before executing the get profile function this function runs before request Handler which is get profile oh it should be jwd o guard jwd guard not and this not this one o card let's rename it to JWT o guard not a JWT guard JWT oard it looks good let's try to access the profile route status 401 which means you did not provide the access token please provide the access token if you want to access this private route so you can provide the exess token by using this format I pasted the token awesome I got the user ID and the email I have applied the OD card and this JWT strategy method will be called first they are going to run the Constructor and then they are going to use the validate function in this lesson I'm going to teach you how to implement role-based authentication what is role-based authentication if your application has multiple roles like artist manager user accountant CFO person you can have a different functionalities for each role in Spotify clone when you look at the Spotify clone only artist can upload a song If you are a user like let me show you you with the help of Spotify web. Spotify like if I go to my profile I don't have any feature to upload a song Only approved artic can upload the song or delete the song in this way you can divide your application into multiple roles we have create songs endpoint I would like to restrict this endpoint for other users only artists should access this create song endpoint we don't have artist module we have to create artist module then we're going to implement the artist module into import the artist module into app module we have to write a method find artist on the B on user ID then we got to add a logic here inside the login method we will save the artist ID in the payload object and then you have to create a new payload type and finally you need JWT artist card we will have a separate card for artist we are extending the jw2 remember I told you if you want to customize or add a logic in the guard you can do that it's just returning a super Constructor and here we are using the handle request method this function will check if you have art artist if you are an artist then it is going to return the user otherwise it will throw the exception we have to refactor the validate method in GWT strategy we need an artist ID then here you will have to apply JWT artist guard on the create song endpoint you can do that as well or you can follow me let me implement it let's create the artist module here we have the artist module it has already imported into my app module this one the artist module we also need R service next generate service and I can say artist you have to import type orm artist entity module. for feature because I would like to use repository here artist repository we have to provide the Artist as an entity so we have the artist service and we also need artist controller artist I can use a nest generate controller artist now we have the artist controller now we're going to create the find artist method I'm going to copy my code inside the artist service let's do it here we need to import couple of dependencies we have to find the artist on the based on user ID our next step is to refactor the login method inside the art service we have to add R service injected we need to add a artist ID inside the payload type inside the payload if password matched find if user is an artist then we need to add the artist ID into the payload what I can say because course I can save the artist ID in the payload object user do p. artist ID should be it is saying that you don't have artist ID in the payload you can create a payload type inside the types p. type I can say types. yes now I can access it I can Define the P type it should be user ID we have mentioned the artist ID is an optional property now we need to have JWT oard I told you how can you implement it we already implemented the O card let's say I'm going to create a new guard inside the O I can say artist JWT godts export class artist JWT guard extends o guard JWT it's a Pur it's a service that's why I have to use the injectable it's a service provider if I will write the can activate you can see that I got the code all I need to call the super Constructor super do can activate and provide the context yep everything is fine you also have handle request now you can write your logic here if there is an error or there is a no user then you have to throw the unauthorized exception if everything is good to go you have to return the user if there is an artist ID then we should return the user get rid of the extra arguments I'm not using them when you apply the artist JWT card it should call the handle request and it will extract the user and try to check the artist ID from the user if you want to log the user you can also do that I will show you what will happen inside the user we created the JWT AR card JWT o card jwd arst card then we have to refactor a little bit validate method in the JWT strategy we can add the artist it should be P type now it looks good we have the user ID p. email and p. artist ID and finally we have to apply the jwd artist card on your protected endpoint in our case we have the songs create endpoint we have to protect it for other users all you need to apply JWT artist card and inside the songs controller I can restrict this endpoint from other users I can say that jwd artist JWT C if you want to log in the request you can do that let's try to do it here request decorator and request I think it should be request it's not a requ request this one request nexts commment and then we have to access the request why it's giving me the error I have to do it here and request now it looks good I can log request. user let's start the application I got the error the O JWT strategy JWT strategy what I did wrong oops forgot to add I forgot to add closing parenthesis if you go to the artist table you will not see any record because we don't have any artist record it's an empty if you go to the users how many users we have I have only single user now I would like to make the artist what I can say what is wrong is au module is a valid njs module Artist Artist service I think we have to import the artist module here inside the are we using the rst service yes we are using the RT service that is why I need to import the artist module and inside the artist module I can say I have to export artist service I want to teach you how to handle errors you must know you must familiar with error handling our application is running now first of all we have to create a new artist I can say let's sign up a new user or I can say that sign up artist let's say that it should be let's say c Martin Garrick Martin Garrick we have registered a user which which should be which could be an artist so if you want to make this user Martin Garrick to artist you have to update it manually but I did not create the endpoint but you can do that I taught you how to do it let's first of all the ID is to I'm going to open all the artist and we have to add the entry this is user number two and finally you have to save it now Martin is an artist so I have to log in as in Martin gar I can say sign up artist or login artist get rid of first name and the last name let's send the login request it should be login I got the token now if you check the profile it should have the artist ID you can see that this is the artist ID this is the user ID this is the artist ID from the artist table this one so it's working fine now when you have to create I for I got I I have to get the token again let's save the token the token will be deleted after one day I can say that arst token temporary if I try to create create a new song it should give me the unauthorized because you are not an artist and you did not provide the authorization token authorization b e a r a r e r now I can say we have artist which is one Mart Martin Garrick has an animal song let's say they want to publish this song I have the artist now it's working fine this is the user ID email and the artist ID user ID email and the artist ID so we got this one artist and the ID colon one we have successfully created the endpoint I can say request. user let's create a new song from Martin Garrick say love again so this is the request. user user ID email and the artist ID in this lesson I'm going to teach you how to use or how to enable how to create two Factor authentication you're going to learn how to implement two Factor authentication if you don't know about two Factor authentication you can read this text a user enters the username and password on a login page page after successful initi initial authentication the system sends you the onetime password or onetime token for the verification a user may provide the onetime code generated by the authenticator app and send to the system then system validate this token if token has validated then you are able to authenticate then you are able to access the route we're going to use third party package to implement two Factor authentication Speak Easy and we need a typing first of all I would like to show you the demo how two Factor authentication works I already implemented in my development project I can show you the demo first of all you got to log to the user I got the access token we're going to create a new endpoint to enable the authentication this endpoint will enable the authentication for the user and it will create a secret key let me show you I'm going to provide this text I provided the token now I got this secret key and I got this response from the Speak Easy package base 32 I saved this base 32 string to my database table for the user is for the user table a user has this record now I I I got this secret key if you have authenticator app Google Authenticator you can you can place the secret key I have enabled the Google Chrome extension I want you to do it when you look at Chrome Google Authenticator you have to enable this extension now I got this authenticator if you have Google Authenticator on your phone or you can install it all you need to do is to add a new app you can also generate the QR code with this OTP path Ot Ot paath OTP o URL you can generate QR Code by using this this URL but you can add manual entry for T testing Sam profile this is the same user the name of the user this is the secret key now I started getting a unique onetime password so I have to copy this password let me do it again it's going to be removed after 1 minute I copied it it's going to be removed yep now I have to provide this token to validate the user I have Pro I'm going to provide it here we also need to have updated token so copy this one and I have to validate the token yes we have to add a new token because it will be expired now you can see you are verified the token has validated now this user has enabled the two Factor authentication if you send the login request you see this message hey you have enabled two Factor authentication you can implement this Logic on your front end application please send the token at this URL please send the onetime password token from your Google Authenticator app on the front end side you can send request to this endpoint and provide the token that's a complete flow of two Factor Authentication let's start implementing two Factor authentication we have to install couple of packages we need a Speak Easy package we will use this package to generate secret key or validate the token onetime password we also need typing add it as a def dependency let's run npm install packages have installed the first step you have to add two new columns inside the user entity do entity I'm going to add them here by default two factor string should be null and it's a Boolean property by default I have set to default to false two Factor secret could be empty and this is the Boolean value when you run the application it should create two new columns for the user property for the user table our application is running now let's refresh the user table I have the 2 FAA secret and enable 2 FAA which is a Boolean column now we're going to create a new method inside the O service to enable the two Factor authentication first of all we need maybe we need a type I can add my type here enable to F type or you can create an interface we have to type and then we need a method you have to create a new method to find the user on the based on user ID if user has already enabled to factor authentication we have to return the secret key if user did not enable the 2 FAA authentication then we have to generate the secret key this is we use the secret key and we're going to use the base 32 secret key and finally we have to update the 2fa secret 2fa key for the specific user and then you have to write the do you have to return the secret key in the response we got to find the user if user already enabled the secret two Factor authentication we have to return the saved to to f secret otherwise we have to generate a new secret and then you have to set this secret for the user user and finally you have to update the user I'm going to copy the code let's do everything inside the OD service I have to create a new method import Speak Easy we also need to import Toof enable type we don't have a method find by ID do we have a method find by ID inside the user service not we have to create the find by ID method you can also do the secret key or unable to factor authentication here use user dot let me first add a new method inside the user service let's go to our next step user service here we need this method I'm going to copy this method now we have defin by ID it is going to accept the ID so we have to provide the user ID you can enable two Factor Authentication to true and finally you can call user. Save method or no we need a repository to save it we also need another method it will update the secret key and enable the authentication you can create a new method inside the user service let me import the update results we have completed the enable to factor authentication now it's time to test it let's create an O endpoint inside the O controller I I'm going to use the guard JWT o guard if you if you don't need anybody you can create it as a get end point I can say that JW the O card I just imported missing Imports we have a login user sign up user sign up artist login user here I can say enable two Factor authentication profile Au enable two Factor authentication let me double check that enable to fa we also need to provide the authorization token so we need to get get the token I got the the access token provide it here let's send the request I got the secret key that's amazing what is the name of the user which is John if you have Google Authenticator on your phone you can install it manually I'm going to add a new profiles which is John user add your secret key it is generating onetime password for 1 minute only we have also saved the key into the user users table let's fetch all the US users here we have the secret key and it has enabled two Factor authentication our next step is to validate the onetime password token let me open it we have created a new user or registered a new user in the Google authenticator it is generating onetime password we have to take this token or onetime password and try to validate with our application we're going to implement this logic first of all you may you may need another endpoint validate to fa we are also using a JWT o card we are getting the request here we will have a method validated to f a token it is going to provide the user ID the logged in user ID and we also need to get the token valid validate token dto we will create validate token dto I'm going to create a new endpoint inside the O controller I created the post because we need to get the token you can also use the get and get the token prams JWT oard let's create the validate token dto inside the dto I can have validate token. D.S now we have to create a new method to validate to fa token here we need to create this method it is going to accept the user ID the token the onetime password like this one this one this one and we will find the user on the based on ID and then we have to get this secret key which we saved earlier and then you have to provide the token and we have to mention encoding which is based 32 if token is verified where is that if token is verified then we have to return verified to True otherwise we have to return verified to false you can also rapar code inside the TR catch block I'm going to copy my complete code and I'm going to paste it here inside the OD service the code is complete self-explanatory now we have to test it we already created the route inside the rest client I can use that and I'm going to paste it here I can say validate to a token validate to fa let me double check my controller validate to fa it's a post end point point and we have to app content type application Json let's provide the token let me get the token John user amazing we got got the verifi to true if I provide the invalid token I got the verifi to false I got the verified false because because token has expired there is a new token we successfully enabled two Factor authentication validated with token you can add you can also add disabled authentication logic or you can have this feature let's implement it by creating a new function inside the OD service it's nothing more just disable the authentication and or set this value we need to have that function inside the user service because we have repository inside the user service I can say that so we have this method disabled to fa now it's time to create a new route to disable the authentication inside the O controller I'm going to create a new Endo here JWT o there is a typo here spelling issue for the O guard J WD o guard e everything is fixed now let's try to send disable authentication request inside the Au controller this is the get endpoint I can have that let me paste it here disable authentication disable to fa it should be disable not an enable so it has disabled authentication you can double check it by login I got the token and let me check it from my DB you can see that it has dis enable false set the false one more thing you can do if you disabled the authentication you can delete the secret key or you can use the existing secret key let me let me do it yeah we have to disable or deleted the key inside the disable validate token disabled I can say to FS secret to set to false or you can set the null value let's try to do the null value let's enable the authentication I got the secret double check it from the DB we have enabled and we have a different secret key I don't want to save the I don't want to change the secret key you should not change the secret key maybe it depends on your use case if client disabl this to fa maybe he has to scan the QR code again let's disable it it looks good we have empty to fa and it has set to false I also have to add this property into my notes if user has enabled to factor authentication we have to customize a little bit Logic for the login method we have to send the link to user this one validate to F token this one if user has enabled to fa and have the secret key then you have to return this type go to the login or service go to the login method here I can add a logic we have to add return type new return type this one let's try to access the login function by sending the login request we have enable two Factor authentication it should give you the link not an access token we have to log in the user where is the login user here we have let's double check it we have empty2 FAA that's why I got the access token let's enable it we enabled the two Factor authentication let's send the login now I got the link validate to fa please send the one onetime password or token from your Google Authenticator app you can implement this Logic on the front end on front end you can send the request to this URL and you have to provide the token a user user has to provide the token so we have completed the two Factor Authentication in this lesson you're going to learn how to implement API key authentication each user will have its own API Keys when he wants to access authenticated route or protected route he has to provide the API Keys when you need to control the number of calls made to your API you can check from your API Keys how many times API Keys has hit if you want to identify the usage patterns in your API traffic you can do with the help of API Keys API key authentication is typically used in scenarios where multiple users or application need to access an API you can read this text you can read the complete flow we're going to use this step we're going to generate API Keys we can create and store API key for each user we have to create an API key strategy strategy service just like we did for the JWT strategy and we have to register API key strategy in a module and the step number five validate the user by API key and apply API key authentication on protected route I have to use external package which is uu ID to generate API key and we will have API key column in the user entity and then when we have to create a new user what you have to do you got to set the API key which is U ID by calling this method it will generate a unique key when you send the when you create a new account it should give you this API key and Next Step you have to create API key strategy when you provide the API key it is going to call this method the validate function and inside the validate you have to call validate user by API key and you have to provide your API key if user is validated this is how you will provide the API key authorization barrier this is my API key we're going to use external package passport HTTP barrier to apply this strategy to validate API Keys finally you have to register as a provider API key strategy this is our method to validate the user on the based on API key if user validated with the help of API key this is our Endo here I'm I can say I want to access the profile on the based on API key or you can create in the O controller use guard o guard you have to provide the barrier it means I want to apply API key valid ation or API key authentication on this route and I don't want to set the send the user back password back in the response that's why I deleted the user password and you can send the message authenticated with API key this is the user this is how you will provide the API key when you make the authenticated request I want you to implement this complete flow if you stuck you can follow my video Let's install the package first let's run the application you will get the error because we have two to three records in users table but it will find null value for API key we did not set the constraint API key should be null if user has signed up we can have the API key or if if you set the null Lael to true you can have a separate function to create the API key for the user it depends on your use case your company or your business logic I'm expecting the null value error from the type orm we are using this database we have all the users you can see I got the eror relation user contains null value which is API key you can fix two or three ways you can set API key value manually but I don't have API key column there is a concept we didn't use the migration but I found the hack to use to resolve this issue I can say Spotify clone 2 let's change the database Run start there it will take some time to create all the tables database does not exist let's create a DB restart the application the application is running fine now we have this database Spotify clone 2 so we have the API key now we need to add the API key when you create a new account I can do it inside the user service or odd service do we have the sign up function here I think inside the users yes we have the create function I have to change a little bit logic I did not create a new user so I'm going to do it here we have to import this package we are getting the user. password delete this one we got it we got the API key yeah I can say saved password I have updated user D to user password and we have saved the password and we have deleted the saved password now we can we have to test it by sending this sign up request open the r client I'm going to send the request sign up request sign up user so it has generated the API key it looks good we have encrypted password it's fine now our next step is to create API key strategy we have to install this package I'm going to copy the same code and create a new file API key strategy inside the O API Das key Dash strategy. DS strategy. DS going to copy the code we are using the passport strategy and we are providing this passport HTTP barrier OD strategy we have to import or provide API key strategy inside the O module register it API key strategy and we have to validate the user on the based on API key I can create a new method I also need to find user on the based on API key let's add a new method inside the user service now it looks good let's create a new controller function into the O controller it means I'm telling to a or nests application I would like to validate this route on the based on API Key njs password everything is good to go right now we have to test the application run the application first of all we have to create a new account I change the email John 13 we got the API key I'm going to store the API key key John 13 now we have to provide this API key to access the profile route access profile we have a get end point get http or/ profile authorization basic here we have to provide the API key it's not a basic we are using this scheme barrier scheme b e a r e r now I got the user back in the response and it has authenticated with API key in this lesson I'm going to teach you how to debug nestjs application using VSS code if you don't have launch. Json file in vs code folder you can create it let's create the launch. jsn file if you go to the debug I'm going to create a new folder vs code and you can have launch. Json file let me copy these configurations so I have to start the application in debug mode nestjs has a script in package Chon file now you can start the application by running npm start Run start debug you can see that our debugger has started now I want you to attach a process when you go to the debug now you have to attach it you can put break points let me to here the O controller I'm going to put breakpoint let's try to send the API request it has stopped at this break point so I can see what is inside the request I have request body request client request. user you can also watch on a specific property the request. user you can see that I got the API key email enable to fa to fa secret this is a great way to debug the application you can find errors very easily by using debugging if you want to debug the complete flow you can do that into the app strategy what I was API API key strategy or API strategy yep we have the API key strategy I'm going to put break point here let me put the break point here and I would like to put the break point here let's send the request you you can see that it has first called this validate method it is going to find the user on the based on API key it has found the user now it is going to return execute this line return user it has now it has added the request. user you have returned API user from the API key strategy like this one nestjs has stored user inside the request object like request. user like this one and finally we have deleted it you can step over it go to the next line if you need to step into a specific function you have to use this one step in if you want to go out from this function you can press step out in this lesson I'm going to teach you the concept of migration migrations is like a Version Control for your database you can manage your database changes by using migrations migration is a file that contains a set of instructions for creating modifying or deleting database tables whenever you make changes in your entity you have to create a new migration if you want to go back to the previous changes there is a command for revert you can use that command once you get into the production right now we are building our application in development environment when we push the application into production you will set the synchronize to false so you have to manually update the changes to for your entities that's why I have set the synchronized to false in production you will not set the synchronized property to True migration is just a file with SQL queries to update database and apply new changes to an existing database I got the simple definition of migration it's called it's like a Version Control for your database you will keep keep track of your changes toward your schema first of all you have to move type orm configuration into a separate file these are all my type type orm configurations now you don't need to write your entities manually when you have to create a new entity you add a new entry for the entity now you don't need that I have added the regular expression for this path we also using the JavaScript because we're going to use migration I found it's easier to work with JavaScript when you are working with with migrations when you build the project nestjs will generate the disc folder this disc folder I can provide that path this is the JS file we're going to provide this type of file I have set this synchronized to false we have created a new data source when you write the script to migrate in package or Json file you have to provide the data source file this this data source and this data source has a data source object this data source object step number two you have to refactor type or M config into app module you got to provide data source options this dat data source options and then you have to write the script for type or M generate run and revert we're going to use all these scripts we will add a new column in the user entity and then we will run run the generate the migration based on this column this is the name of the migration at user phone where we have St about the migration here we have specified the path there is a DB folder and inside the DB we have migrations directory and finally you will run the migration when after creating the file you have to run the migration if you want you can implement this complete steps or you can follow me I'm going to create a new file inside the DB create a new folder inside the root directory DB data source. TS I'm going to paste this code my database is which is Spotify clone Spotify clone 2 so I have to delete everything here we have to provide a data source options this options object I have completed this step number two now we need to add couple of scripts there is no logic logic here specifically you can copy the scripts first of all please build the project generate the JavaScript files then and then we are using the type orm npx and dashd I'm telling to type orm I have stored my database configuration inside this file if if you have to go back or revert the changes you will run this command I'm going to copy this script and paste it here inside the scripts now let's try to add a new column user. entity I'm going to add a new column here here type A String now finally we have to run the migrations npm run migration generate I'm using this script here you are specifying I have I want to store migration in this file migrations and this is the name of the file it will also add the timestamp first it is going to build the project then it is going to execute this command meanwhile I have to start it from the scratch I don't want existing database so I would like to delete Del my database I'm also going to delete this one because we have set this synchronized to false we have to add changes manually that's why we are using migrations and new file has created inside the DB inside the migrations we have this file this is a Tim stamp and the name of the file add user phone. so we have to create a new database I can say Spotify clone now I want to add all this stuff like inside the data source Spotify clone let's generate the migrations I can say that my migrations you can choose any name or in it it is going to take all these entities and creating creating the SQL files SQL queries for all these entities because right now our database is empty in we don't have tables now you can see my migrations if you check the database you will not see any table because we did not run the migration yet now we going to run the migration npm run migration run now it is going to execute these queries these creating all the tables and all the relationships we have the migrations there is no record inside the migrations I'm going to delete this migrations and this migration file let's create it from scratch it has created all the migration now we have to run it everything is good right now it has executed the queries and now if I refresh my tables you will see all the tables we have songs users but if I go to the users I will have font property I don't want font property let's edit a user entity I'm going to remove phone now let's generate the migration I can say removed phone you can see that it has created the migration file removed phone it is going to drop this column now we need to run this migration to update changes in the database let's try to check the column there is no phone column here this is how the migrations work this lesson I'm going to teach you the concept of data seeding data seting is a process of populating a database with an initial set of data when you create a new column inside here when you create a new column in the user entity let's say I would like to add a new column and here I can say this is this could be the phone number but when you run the migrations the phone number will be empty in the database so you can load your initial data by running the seeds applying CED data to database refers to the process of inserting initial data into the database usually when the database is first created let me show you the demo of cing you are going to learn how to create the seed service and we have a seed method inside the seed service we are running type orm queries by using transaction here we have placed all my C data when my application bootstrap loads it will create a new user a fake user and it will save into the database and then it will create the artist and save artist into the user into the database we also have a c data for playlist first of all we're going to create a new user then we're going to create a new playlist and we have assigned a relation between playlist and the user so we're going to save couple of data when you run the application when application will be completed you can verify from your database let me show you in your users table you will see a new user will be created so these are all the users these are all the users I created with fake data by using the seaing I also have a playlist it is going to pick the random name for a playlist Rap playlist World playlist or country playlist I've also have a seed for artist you can see that now my application is is running now when you look at the users you will see another users couple of another users if you look at the playlist you will find one more playlist you can also look at the artist you will have more artist this is how you can increase your development workflow or testing workflow now I want you to implement it by looking at the documentation I created for you here I don't want a new column first of all we have to install another package to generate the fake data and next step we have to create a seeds folder inside the DB seeds I can data seed. TS file I have created a new file while here we're going to do initial seaing you can create a separate function for each entity like you can create a separate function for seed songs I did not create this seed songs method here you can create that if you want to look up more documentation of of Faker package you can find from your from the official documentation page it is giving me the error entities Source playlist here I can find the entity now our next step is to create a new seed module I'm going to use type orm to create a new seed module and then what we are doing here we are generating the encrypted password I use the same password for each user here we are creating the user I got uu ID from API key and I got repository from the manager we will call the seed data in main.ts file seed module has created we also need a seed service what I can do I'm going to copy this code and create a new service inside the seed module see do service if you want you can use CLI to generate service we also have to import or register as a provider seed service cannot find um oh it should be SE data seat should be I can say this seat data seat data and it should be gone we are making connection with our database here I got the manager from the quy manager and I called this C data and finally we are we have started the transaction if transaction if any query has failed it is going to roll back the transaction so our final step you can read this text if you want to learn more about what is cury Runner what is transaction here you have to boot you have to call the seed method here whenever you want to save a data in the database if you don't want to save a new fake data you can just disable these two lines but let me show you the demo I'm going to start the application it is going to run these methods seed user it is going to create a new fake user seed artist and Seed playlist let me show you the current look of my schema I'm using spotify clone on database Let me refresh my tables uh I would like to see all the users there is nothing here I don't have any user you can create many users if you want you can use fake package to generate 20 15 50 55 records and you can and then you can provide into the repository user repository it will create all these records but I use a single record I just want to show you the process you can manipulate with your own use case one more thing I could not find the official package or official documentation or in typ orm seeding I got I have implemented my own strategy now my application is running you can see I have couple of new users you can see I have couple of new artist I think I will have only single artist yes but if you look at the users it has picked a random first name random random last name random last name and the email and the password and the API key it has generated one more thing if you want to look at the playlist I will also have a one playlist electronic music song that's how the seeding work works whenever you create a new entity I would recommend you to create a seed function whenever you run the application it is it is going to create a new data but I'm going to comment this code you can enable the seaing here if you want to make it more Super productive you can create a console command in njs I'll teach you in the advanced Concept in this lesson I'm going to teach you the concept of configurations we're going to create custom configur ation file with the help of nestjs config if you see our main. file I have mentioned the port number manually if you want to have a separate port for development project or for production environment you can specify in the environment variable we don't have any EnV file in if you have worked with nodejs you will have separate EnV environment file. EnV file for development and you you will have separate. EnV file for production one more thing if you look at our type orm configurations here we have type orm configurations I have specified a username manually password manually database manually I also specify the host manually what if you want a different environment variables for production let's say you want to deply the project to AWS or Hoku you need a separate en andv environment variables for production level but we did not Implement that logic now we need to do it if want to read what is configuration you can read this complete text I have explained configurations you may need a database setting for in for development and production you may have different API keys for production and API keys for development you can have multiple environment files for production production and testing nestjs provide provide config module we're going to use this package I'm going to copy it and I'm going to paste in my dependency section or if you want to install manually you can do that I have to do npm install in The Next Step you have to import config module in the app module this config module will have config service and we're going to use the config service to access the environment variables let me show you how can we do it package has installed now we need to import config module into the app module geted of these extra dependencies we have to import it here let's import config module so here we have config module after importing config module you have to provide the path of your EnV file here you have to provide the path we don't have any EnV file go to your root directory and create two files the first one for env. development for production level I can say en EnV for production this one is for development and this one is for production if you want to have a separate port for different environment you can do that but I'm going to keep with 3,000 for production you can place it here so we have created the EnV file so how can you load this EnV file we have to set the path in the app module here I have to provide the options configurations I can say EnV file path it can access the array the first one is do env. development and do EnV do production one more thing I would like to mention we have used the config module inside the config module config module is using do EnV package if you Google the envv this package is used to define environment variables for different environments for development and per for production but by default nestjs config package is using the EnV we have used this load ENB property so what you have to make it Global let's say I would like to import EnV module into my Au module into the artist module let's say I want to use API keys from env. development file to artist module you don't need to import config module you can use config service automatically but if you use if you make a global when you want to use config module in other modules you will need to import it as it standard with any Nest module or you can make it Global I have set it to Global so I can use config service without importing the config module now we have to create the custom configuration file you have to create a new folder inside the source folder I can say config let's create the configurations here you have to place all your configuration you have to define configuration inside the EnV file and this configuration dots file is is going to fetch or add validations for environment variables inside the configuration so config module is going to use this configuration .s file it is going to to extract all these values from config does let me show you how we have to load our configuration file custom configuration file I can say load you can have multiple configuration file you can have different configuration file for database you can have different configuration file for app settings or user profile settings something like that but I'm going to keep it simple let's use a simple configuration file we have to import the configuration now our next step is to test the EnV variable we have created the port and we have defined or getting the port from uhv and here now let's say if you want to access this port variable I'm going to do it for testing purpose don't do it in production inside the O service let's say I can define a new Vari new function get EnV variable you can call any function here here how can you use the configuration dots file while how can you get the this port into your a service like we have to inject the config service we have to inject the con config service config service remember I did not import the config module into the Au module because we have set it to Global in the app module so we can use config service config service. get pass it into as a integer you have to provide the name of your key which is Port when you open the configuration. ES file we have specified the key which is Port so how can you use this function let's say I'm going to create a controller function for testing don't do it in production I just want to show you the demo I can say test get EnV or you can say test EnV variable it is going to return this do out service calling the get EnV variable that's it do not do any fancy stuff here let's start the application and we have to test this route now we need to test it I have to send the request to this URL this endpoint we have to send the get request can say test EnV 3000 sl/ test amazing I got the Port Port value which is 3,000 it's working fine now now if you check the main.ts file we have defined the port into configuration we are using the port value manually I would like to use the config service here I want to get the Value Port value from the config service and I would like to use it here this is how you can do it you can get the config service instance from the by calling the app.get method and providing the instance providing the config service class it is going to give me the instance config service then I can use the method here so you can do it here config service you can import it now I can get the port value service. getet let's pass it as a number here I can say the port which is key get rid off this no I'm not using seed service we have our application is running fine now let's send the test test request test I got the port 3000 we successfully configured the port in the main.ts file now we also need to add our secret key inside the EnV file we are using getting the value from the Au constants but I don't want to get it from the Au constants I would like to add secret key inside my EnV file I have to place it here secret now I would like to use this secret we are using this secret inser the app module inser the Au module not app module here we are using the O constant. secret but I want to get it from the config service I want you to think about it how can you add or how can you get the value from config service we also need to add a property in the configuration I'm going to do it here and this is how you will get the value from config service we have to register this module as a async and and it is going to return the dynamic module so you have to follow this pattern if you want to configure Dynamic module Dynamic module is a feature that allows you to dynamically configure and register modules at runtime based on Dynamic conditions so we have this Dynamic value so what I want you also have to inject the config service you have to import the config module this use Factory is used to inject the config service and we are getting the value here so I'm going to copy that I'm going to replace my Au module with this code import config service and config module Imports I don't want to use the O constant get rid of the Hat we have to import config module we also need to import config service that is it now we have specified The Secret inside the configuration did I Define the secret in the production I think I did not if you want you can do it env. production let's restart the server our application is running successfully it means we successfully configured the secret key you can test it by sending the API request I have to open it here rest client I can send this signup request it's oh I got I sent the login request we have to send the signup request user has created successfully it's working fine now now our next step is to configure the DB configurations database configuration I'm going to add the configurations inside the my EnV file development file if you want to add a separate EnV file separate configuration for database you can do it can say that DB configuration my database is end test now we have to define the values inside the configuration. ES file I'm going to copy the same code or I need these values now we have to update or refactor the manual values with configuration config service so I I'm going to create a new type orm async config object and then we're going to use inside our type orm module let's refactor it you have to create it this is the same process you have to create this module or register this module as a dynamic I'm going to use the same configuration when defining the type or a module I'm going to do it here you can import type orm config options we also need to get config module and config service type or module options I got the DB host DB Port username DB name password entities and synchronize set to false here we are going to get it from the process.env I'm going to copy that code and I'm going to paste or you can say replace this text host inside the app module we have to register it type orm module this time type orm ASN config get rid of data source wrong driver I think something is missing postgress we have to use the for root async in the app module I think that is why it is showing me the error you can see that application is running fine now it means we have successfully configured the database we have successfully configured the settings it's working fine now in the previous video we have created the environment variables we have set up the DB configuration DB Port username password and database name we if you want to add the validation if you want to validate these environment variables you can also do that with the help of class validator package to implement the validation you have to create the env. env. validation. TS file we did not add node EnV inside the development or production. EnV I have set the Isam which is enum here I have defined the validation for Port DB host username password DB name and the secret we're going to use class based validator class validator package that's why I created the class and we will have the validate method it is going to accept the config object with record key value pair first of all we're going to use plane to instance from class Transformer package plain instance converts a plain literal object to class based Constructor object you can learn more about class Transformer by looking at the doc so class Transformer allows you to transform plain object to some instance of a class you can look at the documentation of class Transformer if you want to learn more about it and you have to enable this property to true and we have to provide the environment variable which we have created the class this one environment variables and we have the config SE config object you I'll teach you I'll show you what is inside the validated config now it should be the instance of a class if error comes you can send the error back otherwise you have to return the validated config and then you have to provide this validate method inside the config module we don't have node EnV you can create inside the environment variable let me do that first env. environment I'm going to copy that in the production I'm going to copy here now you have to create a new file inside the root directory env. validation. TS file file we will have the enum for development environment it could be development production test and provision now you have to create a class to validate the environment variables we have Port dbhost username password and the secret now we have to implement the logic for validate function it should return the validated object validated config so I got the instance of the class we provided the environment variables here let's say if I would like to log the config I can say please log the config and here I would like to say please log validated config now we have to perform the validation there is a validate sync method you can use it let me import them I'm going to import them here if error comes we need to throw the error otherwise we need to return the validated object validated config object so we created the validate function now it's time to register it inside the app module I'm going to register it in the config module here there is a validate we have to import the validate you have to import it manually it's not giving me the suggestions can say validate from it should not be EnV it should be env. validation that's why I'm not getting the suggestion because this is a typescript file it's not an environment file now I should get the suggestion for validate let me import it from env. validation do not import it from the class validator package I would like to test this application you can see that we have I have the config object inside the the config object I have the property Port secret node EnV DB host we Define these properties inside the environment file. env. development I got the DB name all these couple of things now you have environment variable which is the instance of a Class A Class based object in environment variables I got all this port all this stuff I'm going to comment this out what if I set the wrong value in the development file let's let me test it if I set the DB Port should be string let's say that it should give me the error I have to restart the application because I have made changes in theb do development file I did not set the validation for DB Port that's why I did not get the error let's say I'm going to do it here DB Port I can say the type should be number I have saved the application I have to restart it you can see that I got the error property DB Port has filed the following constraints is number let's replace the DB Port we have successfully implemented the validations for environment variables in this lesson I'm going to teach you how to increase the speed of module reloading what do I mean by module hot reloading if I change anything here in any file it will take too much time time to reload the application if I'm going to log something here now my application is running first time it will take some time let me show you the problem and what problem we're going to solve and how we going to solve that problem e for in this lesson I'm going to teach you how to increase the speed of nestjs project reloading if I make changes in any file let's say I'm going to delete this code it will take some time to reload the application I would like to increase this speed with the help of web pack you can see that it's taking too much time to reload application nestjs provides a way to increase the speed of your hot reloading you can see that it's still calculating the changes it's still calculating waiting for the file changes I think it has took 30 seconds to load the application let's increase the speed with the help of weback first of all you have to create a new file web H hot modu reloading doc config you have to create this file inside the root directory and I'm going to copy this code because I'm not not going to teach you weac in this course and step number two we have to make some changes in bootstrap function I can open the bootstrap function in the main. file we have to add the code here if module. H then you going to do this process it is asking me which module I going to talk about let me check it from my project yes I need to declare module as a variable I can I would like to declare it here I can also add that part into my documentation now our third step is to add a script to use web pack instead of default configuration to run the project in development mode we have to refactor the start dep script I would like to change it and let's do it this time we're going to run the project with web pack e cannot find run script weback plug-in do we need to install it oh yeah we need to install it e make sure you installed it as a Dev dependency so I need to uninstall it now we need to install it as a dep dependency let's run the project weback is building your sources project is completed let's try to send the API request but it's still running first time it will take some time to initiate the project now project has completed it's time to send the API request I'm going to send API request to root URL let's say I would like to make some changes I can say hello world I saved the application now you can see that it took 2 to 3 seconds to reload the application updated modules you can see that it also loged the message updated modules so I'm going to move this line application has started again I found it's very helpful when you are building a project in development environment we're going to use Swagger package to document the apis if you don't know about Swagger it's an OP Source software Frameworks that enables developer to document and design the restful web services it provides a set of tools and specification for defining the structure end points and data models of an API we will have Swagger specification Swagger editor and Swagger UI if you haven't looked at the Swagger let me show you the demo this is the example of swagger documentation you will have all the end points what these end points are doing you can look at as you can see that we have profile route we have all these routes available you can also create a section for each each route I'll teach you how to do that so I just want to show you this is the overall view of swagger documentation so we have to implement it first of all you have to install a third party package which is nestjs Swagger uh Swagger Nest has created this package let's install this package or I can add into my package.json file let's install it Swagger package has installed now we need to configure this Swagger module in bootstrap function you have to do it here you can use document Builder from a Swagger module you can have to set the title title should be Spotify GL the name of your application and you can write the description for your application you can set the version and finally you got to call the build function and then we will create the document with the help of swagger module and you have to provide your application instance and this config module this config setting and here we're going to mount the Swagger document at/ API route and you have to provide the application instance and your document I'm going to copy the same code and I'm going to place it here inside the bootstrap function you got to do it here let's import Swagger module I'm not getting the hints for Swagger module and document let's import manually cannot find a module nestjs worker why I think I have to install it manually and install next just swager now the error is going now we have a Swagger dependency here we have the nest F package you can write the name of your title application and you have to write the description version and finally we got a call the build and we are creating the document and we have set up the Swagger module it's time to run the application oh there is an issue it was an extra parenthesis application is running now let's try to test it I can go to the Local Host colon 3000 SL API now we have the title of the document and the description we have all these routes but we did not add the tags I'll show you tags in the next video let's try to send the request to the root URL so I got this response hello I am learning nests fundamentals if I execute this endpoint I got the port the 200 status code in this lesson I'm going to teach you how to document this signup route if you look at this signup route I don't have any schema yet it's not displaying the schema what type of parameters do we need do we need first name do we need last name I also want to show the description or the purpose of this signup route first of all you have to add the API tag to the O controller let's convert all these routes into o section we're going to place the login route into OD section enable to fa and validate to fa let's do it first I'm going to open the O controller here I can say API tags I can use the Au my application is running now you can see all the routes are placed inside the O section one more thing I would like to add in the O controller we have to decorate the sign up route the next step we have to add the API operation and the response I'm going to use the API operation we need to get it from this Swagger module it will return the user in the response with 2011 status code this is called please register a new user make sure it's running now let's refresh I cannot see the sign up rout I think it is taking too much time oh I found the error API response we need to get the API response yes we have the API response let's restart the application now you can see that we have the register user we have specified it here somebody which is registered new user and you can see the response it should it will return a user in the response let's try to test it if I if I provide first name NH last name shsf and we have to provide email SN gmail.com let's provide the password 1 2 3 4 5 let's try to test it out internal server error because let me look at the error entity metadata note found no metadata for a user was found I found there is an issue with type orm and a web pack if you use vbac hot reloading like we have used weac package to reload the application fast type orm does not work with this configuration like this one we have to replace it and you have to register all the entities manually but it can work with migrations there is no problem with migrations but you have to replace it here we have to import couple of entities application is broke now I think I have to restart it application is running fine let's test it out I'm going to create a new user a user has created successfully you can see that with 2011 status code when you look at the sign up route if you check schema it is not displaying me in the schema what do I mean by schema here I cannot see the login dto I don't have create song dto I don't have create user dto it should display me the schema let me run the application my application is running now if you look at the schema in the signup route you will see the empty create user dto you can fix it with the help of API property you have to tell Swagger hey this is the API property I want to I want to see in this Swagger document let's add API property in the user entity we have to do it here please provide the first name of the user first name of the user let me import API property you have to do the same thing for last name you can also add example like what could be the data type look like I'm also going to add API property for email let's do it for the password my application is running now but I cannot see this schema value I cannot see properties here for my schema you have to register nestjs Swagger plugin you can do it in the nest CLI I'm going to copy the plugins open nli and I'm going to do it here let's restart the application because we have modified nli let's refresh the application I cannot see my schema I have to register the plug-in inside the compiler options that was the mistake restart the application now you can see the schema value first name last name email and the password it will also show you the schema value for login dto here we have the user example value email ID API key playlist in this lesson I'm going to teach you how to test Authentication in Swagger document we have to enable barer o it's a scheme you can do it in main.ts file you have to add this function Nest Swagger module provides this function add barrier o this is the type HTTP scheme is barrier format should be JWT name is JWT you can add you can add the description jwd token and I would like to provide in the header this is the name when you need to use or apply on the controller function one more thing we also need to update the secret key in the JWT strategy I don't want to use o constant. secret I I have to get it from the process.env secret this get profile is our protected route if you want to apply authentication or app if you want to protect or apply authentication of swagger document you have to use the API barrier a and this is the name we use jw/ here this one like create songs endpoint is also a protected route you can also apply authentication on that in the songs controller these are all the protected routes only artist can access update endpoint delete endpoint and create endpoint so you can apply Authentication on these routes as well but I just want to show you the demo in the app controller we have this protected route get profile endpoint let me show you in our Swagger document SL API here we have login route we don't have any authentication section let's implement it first of all let me write documentation for login route inside the O controller it looks good now we have to enable the authentication I'm going to copy the code and paste it here now we have to apply JWT authentication we also need to update the secret key in the JWT strategy I don't want to use o secret from the O constants let's get it from the environment variable and this is we have to use I'm telling to Swagger hey Swagger this is the protected route application is broken now restart the application I found an issue when you are working with we hod module reloading do not save the application if your application is in error format if there is an error in the file do not save the application otherwise it will break the V hod module reloading now it it will take some time to restart the app application application is running now I have to refresh my page now you can see the authorize if I try to access the profile route from here it should give me the error unauth red so you can you have to log in to get the access token I'm going to send the login request password does not match what was the password 1 2 3 4 5 6 I have got the access token now I can use this token and I'm going to provide it here this is the name JWT o you can see that authorize Now by enabling this JWT o here this Swagger will use this token just like we saved here let's access the protected route you can see that I got the user ID and the email it has already attached authorization barrier and the token if you have all protected routes in the controller you can also add API barrier or here for all controller routes but I have only single route is protected protected this is the public right route that is why I did not use the API or o barrier or inside root inside the controller for a controller so I applied separately API or API barrier OD you can also Define the tags for songs controller I want you to do it you can apply High authentication on songs controller protected route like create is a protected route you have to add API or o barrier decorator here it did not create the aay tax because my application has broken now by using this code restart the application my application is running now I can see all the songs related route you can also do it for the playlist API TX you can see the playlist section in this lesson I'm going to teach you how to install mango DB using docket compose if you don't have installed mongod DB on your machine you can install it manually or you can install with Docker compose I have already installed Docker on my machine my Docker is running you can see that here is my Docker is running now but we don't have any project right now to use with mongodb I don't want to install mongodb in my previous project we're going to create a new project to play around with mongod DP database I want you to create a new project I can say Nest new and we need to provide the name of your project I can say n production nestjs project with mongod DB and I want to ship it on production level you have to choose your package manager I'm going to use npm it will take some time to install the dependencies my project has created successfully all the dependencies have installed I'm going to go to my project I'm going to open the project into my vs code let me run the project by using npm Run start Dev let's commit in it and I would like to create a new Branch I'll store this code into this branch to connect with mongodb we will install this dependency or this package in the next video or you can install it here we need NCS mango package and we need mango separate package this is the magic we need to implement we're going to use docket compose to start mang DB driver I'm going to create a new file in the root directory I can say Docker compose EML you have to Define your version I can say one you have to define the services here we need to define the service mongod DB or mango mongodb the name of the service you have to provide the environment I can say mongod DP database and we need to provide the name of the database which is test we also need to provide the image we need to get the local uh latest image from the docker repository Docker Hub or you can say let's define the port I'm going to copy the same code I don't want to make mistake that's it or you can change your database I can say Spotify clone now you have to start MB driver you have to execute this command do compose up my project I'm going to open my project into R directory and let's execute this command I think already allocated I think my already project is running on 2701 docket compos let me stop that project project here we need to stop it let's try it again now it is going to start the mongod DB I'm also going to use external tool it's a graphical user interface mango DP Compass you can install it you can play around with GUI with mongodb database this is the GUI mongodb mongodb Compass you have to have a new connection you can have a new connection it is going to ask me the host and the port I can say Local Host and this is the port 2701 because my mango DB is running on this port 27017 so I'm going to connect it and you can create a new database Spotify clone and you can have the collection which is songs you can see that I have interacted with mongodb database and I created a new database so our mongod DP driver is running successfully in the next video I'll teach you how to connect nestjs application with mangos or mongod DP in the previous video we have installed these two packages mangos and nestjs mangos if you would like to connect nestjs application with mango or mango DB you have to create a new module in the app module you have to create it by calling the for root method this for root method is similar to mango. connect from the mango package you can read the connect package from the official documentation what I want you to make sure your mongodb is running my mango mongod DB driver mongod DB is running with the help of Docker I use Docker compose up here it is running Docker compose up now we have to call this method mongos module. forward in the app module make sure you have this database Spotify clone if I run the application let's see what will happen npm runs start def mango module because we did not import it let's import it with the help of VSS code I'm going to save the application you can see that Mango's package has installed it has also initialize the mango score module dependencies it means we have successfully connected to mongod DP if I will write the invalid Port let's see what will happen I'm getting the error mangos module unable to connect the database so it means we have configured the mango DB with nestjs but if you look at mango Compass I think I don't have Spotify clone database it can work without creating the database if I create the database it will work I can create the name of the collection now we have Spotify clone it looks good now we're going to create schema using mongos model in mongos everything starts with schema each schema maps to mongodb collection and different finds the shape of the document within the collection schemas are used to define the models and models are responsible for creating and reading documents from the mongodb database so we're going to create the first schema you have to create a new folder songs here you have to create the schemas folder and you have to have a schema which is songs. TS file but we will use this song document when we will inject the model into song service you can use the decorator schema nestjs mango module provides schema decorator this prop represents the property in the collection we will have songs collection and inside the song collection we will have these Fields Title release date duration and the lyrics Yep this schema decorator marks a class as a schema definition it Maps Our Song class to mongod DP collection of the same name but it will add S at the end of the final mango collection name will be songs and prop decorator defines a property in the document and finally we will have schema Factory it will return the raw definition of schema I logged on song schema and I got this result schema object we have these properties title release date and duration and couple of metadata for each field this is how you will create a schema I want you to implement it so I'm going to implement here by creating a new folder inside these songs we will have schemas here I'm going to create a song schema or song. TS file I just pasted my code we have defined four Fields I got all these properties from our previous project which we worked with tym and post I got title release date duration and lyrics I set this data type for dur string I couldn't find a Time Field Time data type in mangos so you can validate manually duration by using third party date plug-in so we created the schema successfully this lesson I'm going to teach you how to save record in mongodb database we're going to save record card in mongod DP collection right now we don't have a songs module we don't have songs controller we don't have song surveys we're going to create all these stuff and then we're going to create post end point inside the songs controller you have learned how to create the post endpoint how to create network request object or data transfer object dto and then I'm going to use song song service song service has create method to save the record in mongodb collection and finally we will create create song dto object inside the create song d. file and here I would like to inject the model remember schema will act as a model you can use schema to generate a model so I'm telling please give me the model the name of the model which is songs and I would like to use here I would like to inject it as a dependency I remember I have created the type in the song schema file I got the song document and this song model provides crud operation create read update and delete it is similar to type orm repository it will be treat treated as a type RM Repository and finally we have a safe method in the song model and I am going to call the method here it is going to return the promise and finally we have created the songs module we have to inject the song model just like we did with type orm repository if you will not do that part you will not be able to inject song module here that's why you have to register it as a here I'm telling to njs I would like to use song model in the service or in my provider and then you can send the request to this URL to to create a new song in the mongod TB collection I want you to implement it let me implement it for you let's generate let's generate controller songs let generate so service songs it has created the songs module it has also updated the entry in the app module you can also see the songs controller it has also updated Creed the songs controller inside the app module you can see that now we have songs module inside the songs module we have songs controller and the song service now it's time to create a new endpoint I'm going to copy the code inside the songs controller we just injected the song service right now this create method does not exist in the song service we also don't have create song dto Let's create let's create create song dto I'm going to create a new folder dtos and I'm going to create a new file file create song hd.s file that's it I already taught you how to create a method in the service let's refactor the song service add a new method we have injected the song model make sure you provide the name of the song model here we are injecting the song model and I called called create method from song model and finally we have to tell njs I want to use this song model in the songs module so please make it injectable and now we have to run the application I have to import song dependency song it looks good we have to test it I'm going to create a new file to make API request I can say api. HTTP let's send the API request you can see that a song has created we can verify from Compass here is the record inside the songs collection let's add another song so we have another song it should display the second song but I cannot find out no I can see the second song we have two records in mongodb collection this is the document if I don't set the title what will happen you will see internal server error because we have set the validations inside the song schema these properties are required title is required release date is required and duration is required in this lesson you're going to learn how to implement find and delete method we will create two endpoints to handle find and delete request let's start implement it I have already taught you how to implement crud or rest based API end points let's create a method find to fetch all the records from mango DP collection it is going to give me all the documents now we have to create a route to handle the request our application is running now let's send the API request to fetch all the songs we have to send the get API request we don't have any record yet let's create a new song I have I've created a new song I'm going to create another song now we have two songs let's fetch all these songs we have successfully implemented the find all method now it's time to implement the find by ID I'm going to create a new method find by ID in the song service and there is a method find by ID in the song model you have to provide the ID we're going to get the ID from the request parameter let's create a new route now we are going to send the request to fetch song Only based on ID find one song we have to get the ID I'm going to send the request to fetch all the songs now I'm going to copy the ID and we need to provide the ID here so I got the single record on the based on ID you can also implement the delete endpoint I'm going to create a delete function inside the song service song model provides delete one method and you have to provide the ID mango work works with underscore ID if you have worked with mongodb the ID stored ID stores in this underscore ID format if you if you are using or have used postgress or MySQL in my SQL or postgress you say the primary key or primary ID with this ID without underscore now we have to create a delete endpoint in the songs controller we have to get the delete method that is it let's create a new song because we're going to delete that song I'm going to get the ID and now we have to delete the song to send the delete API request delete song you can see deleted count is one acknowledged true it means we have successfully deleted the song you can double check it by sending the API request to fetch all the songs and you can see new song does not exist here you can also implement the update functionality I already taught you when you were learning type or mcard operations similarly you can implement the update operation you can have you first of all you have you have to Define update function Here song model provide the update method you can use that method and then you got to create a controller to handle the update request in this lesson I'm going to teach you the concept of populate if you want to make a relation or a reference between two document between two collections remember in mongodb collection collection will have documents in my SQL or post you will have tables and columns so if you want to make the reference or relation between two collection you can do with the help of poate you have to implement the concept of poate I have this use case or scenario each song must have must belong to one album and each each album can have many songs I want you to implement it if you want to do that you can Google Mongo's relation or check the official documentation this is our album schema we did not create the album schema yet I'm going to teach you how to do that or you going to create or you can create the album schema just like we did the song schema scha it is going to take the array of the songs because each album can have many songs that's why I created the array of songs and you can have multiple types it's an array I got the types from mango package here you will see type from the mangos and I'm telling that the reference is songs because when you create the song when you created the song schema you have defined a class for class song by default the collection will be songs you can also double check it from mongod DB Compass let me show you I'm telling you I would like to make a reference with songs collection let me do that inside the Spotify clone we have the collection name which is songs I have added the reference here and finally you also have to add a relation for this for the album in the song schema I'm creating a property and type should be Mango's object ID or mongodb object ID here I'm I'm getting the or defining the reference album. name it should be albums and we have the album and finally you got to create album module just like we did the song module and I'm saying I want to use the album model in the album service or we we will be able to inject the album model to perform crud operations and here I have injected the album model in the album service just like we did songs model inside the song service and I created a new method we will have a create album dto and here we will have find albums this is how you will implement the populate let's say you want to display all the songs on the front end against each album then you need this query you got to I'm telling to mongod DB please give me all the albums please give me all the albums for each Album please also give me all the songs this is how you going to do it and create when you are trying to create a new album you got to provide the title and the songs it should be the IDS and we have create method to create a new album and uh find all albums and you also have to refactor create Song D you can implement it I want you to do it I already taught you all of these steps to do that first of all we have to create album nextest generate nextest generate module albums or I can say albums and next gener at controller album and Nest generate service albums Nest generate module albums Nest generate controller albums Nest generate service albums I don't need spec files I'm going to delete them now you have albums module albums controller and album service it has also added the entry in the app module let's create a new folder schemas I have to create create a new schema I can name it to album schema. we will also need a dtos now we're going to I'm going to copy album schema and I'm going to paste it here that's it and I can use I also have to refactor the song schema we have to add another property one thing I forgot to add it should be a mongodb property that's I forgot to add add prop decorator for the lyrics property we need to get the types from object ID from mango we also have to import the album from album schema everything is good right now let's create we have to update album module actually we need we need this line I'm going to copy everything e we don't have dto let's create that create Alum dto now we have to define a controller we already created the controller I can say should be albums controller album service and we also need to refactor the create song dto I have found the error in the album service get rid of the song Let's import it here if I save the application we also have to refactor in the song schema everything is good now what we what I want to do I would like to create the album first create album we have to send the post request by providing the data it is going to get give it is going to asking me the name of the album title title of the album let's say dance and I would like to provide the array of the songs I want to save let's say these two collections these two collections inside the dance inside the dance album I'm also going to save this document or save the song inside this album let's create a new album I got the eror song validation failed duration duration is required OMG I forgot to add the albums here now you can see that I got the dance album with these two songs now we have to fetch all the songs I'm going to test the popular method popular functionality find all albums with songs this time we have to send the get request let's fetch all the albums you can see that I got the albums array this is the first album and we have all the songs against each album this is how you can make a relation or reference with document with collections or with models in this lesson we're going to prepare our application for deployment I'm going to teach you how to deploy nestjs application at Railway you will also deploy your postgress database at Railway we're going to deploy our application this one the Spotify clone which we were building our application is using postp database with type orm I'm going to teach you how to deploy the complete application at sailway first of all you got to create a new project make sure you deploy your project at GitHub repository I did not deploy the project yet first of all we have to do a do a little bit configuration we have to set our environment variable when I will run the application in production it should run this production. EnV file if I'll be working at development environment I want to work with local post database I don't want to change in production level so we got to configure a couple of settings we already created the env. development. env. production but it is not configur configurable when my project is running in production mode it should pick this production file I've already written down the validation in EnV validation for node environment but I did not set in the configuration let me do it I can say node EnV and I can get the value from process dot process. env. node EnV now this variable is available for the config service I've already provided you the nests deployment raway started kit BR started kit project you have to open it and run npm install to install all the dependencies now we have to configure the EnV file path in app module get rid of this stuff I don't want to do it configure get it off this middleware get rid of this data source here we have to update our path what I can say please get the value from process do do EnV do node EnV or you can say get the path from the current working directory and you can provide the name of your file current working directory and Slash dot here we need to do EnV dot development or production we have to remove this one please get the working directory and find the env. production file or env. development file we have to set the script or we have to set the development environment in our package.json file for the dev I can say I want to mention node EnV to development we have to do it here we have to set the production value when you run the application with production how can I test it in the main.ts file maybe I can use that or what can I do yeah I have the access to config service I can say console DOT log config service doget I can provide the name which is not EnV let me part it to string let's see what will happen you can see that it's working fine now my application is running in the development environment if I run the application in produ prodction environment when you see the production. environment I don't set the I didn't set the database configuration so it will not work my application will be crashed let me show you you can see that my application has crashed an instance of environment variable has failed yeah it is showing me the validation error dbport does not exist DB host does not exist if I copy this configuration what will happen now it should run the application you can see that my application is working fine now but we will replace these configurations with Railway post configuration I have everything in the master Branch let's create the GitHub repository because Railway will be asking for GitHub repository let's create a new repository I can give any name nextjs deploy to railway if you want you can create private repository I'm going to make it public we have to add origin it is asking me to create push as a main branch let's do that so I got the main branch everything inside the main branch let's try to check it out so I have everything in the main branch now we have we have EnV doev development we have env. production you should not push your env. development or env. production to the GitHub repository because we wanted to set it to the kit ignore do not add Dov files if I add. EnV update get ignore we have to push the code I try to add do EnV in the G ignore edit I try to add EnV in the ignore and it was not not working I also removed the cache for env. development and env. production file removed envs now we have to push it oops envs let's push the code let me delete this file manually I'm also going to delete env. production now we got to pull the code everything is up to date right now if I try to push you should not see env. production and EnV do development file so we have pushed the source code to our GitHub repository you going to say deply from the GitHub repository here we have to configure our repository I can say deploy njs app to I can say now it is going to deploy the code it is building and running env. production no it is trying to building the project now you can see that our project has deployed if you want you can see the log what is going on here I got this error instance of environment variables has failed in the valid validation that's an issue we have to configure our environment variables our application has crashed now we have to set the environment variables first of all I have to create a new database it's very easy to create a database in real way just right click and find the database I'm going to have post now you can have the post when you see the connect here you can find your database option I can say this is post and you can up create your EnV production file EnV production oops I deleted that files we need to get back our development. EnV file do env. development and I also need to get production EnV file now I'm going to copy my database in the production let's do it here database this one and we need PG Host this one and we need password I want you to use your own password do not copy my password username it should be post it's working fine you also need a port everything is good to go now now I want you to copy these EnV file the your production EnV file and open the N nestjs deploy to raway project and in the in in the variables you have to set your environment variables that's it I'm going to update my variables now it is going to redeploy the app application now redeployment is in progress It's Time to it's it will take some time my application has deplo deployed now it is going to start let's look at the deployment logs amazing I I was logging the production in the app module or I think I was doing in the main.ts file you should not do that it's working fine it means we successfully deployed our application so how can you test it maybe you had thinking about it how can I test this application right now we don't have any domain let's generate domain to test the application uh if you want to refactor you can change that I can say Spotify clone production now we have this domain name I'm going to open it it is going to give me the nothing here don't worry when you try to access the API routes it will take some time because we have set the domain name it is going to take some time now it's working I think fine now after 30 seconds my project has Reloaded now we're going to figure it out I'm going to send the API request to test the application it is working fine now but what will happen if I try to create a new user let's say I want to perform database operation I'm sure it is going to give me the error let's create a new user Jane Don Jan gmail.com 1 2 3 4 56 I'm going to send the request I got internal server error you can check the log what what is going on users does not exist because my database is empty now we did not implement the migration remember you have seen in the data source we have set this synchronized to false but do not use synchronize to true in production what we have to do we have to run our migrations to perform changes we have to add relations because I done that I've done it I think I don't want phone migration you can delete that now I have to execute these queries these queries will create table in our postrest database here here what we have to do we got to run the migrations I got this issue we have to migrate the database in the production so we have to use a migration make sure you are using the password process. env. password not a DB password because we have defined the password in our environment file we have to run the migration I'm going to run the script npm run migration I would like to create all my tables that's why I just provided the name in it so I got the undefined process. I'm doing the log for node environment I'm also doing the log for DB DB host I'm also doing the log for DB password you can see that I got the development value it is working fine but when you look at the env. development I'm using the database for the Local Host like post gra local instance here I'm using the railway postra instance so I have to tell to nestjs build command under the they are using generate command is using njs build command this one type orm but I want to say please run the produ run the project in the production let if you want to run the de in migration in production you have to Pro tell njs project you can create a separate script for build for production or separate SCP for separate script for build in the development environment but you can do quickly by using say that export node EnV here I want to set the node environment variable to production now you can see development environment should be in the production I'm going to run the migration I've also logged the node environment it should give me the production by default it if it if it logs production it means it is going to run the production EnV this one you can see node environment is production but I got DB host is empty undefined and password I figured it out the issue I have to install do EnV package and here we have to use the EnV package it is not getting variables from EnV because we were using the config module for config configuration after installing config module do EnV package you have to import it here do en/ config now you should be able to access these variables so I'm going to run the migration before running the build you have to set the node envirment do you want to run it for production or do you want to run it for development but if you want you can create a separate script SE separate build script for production and development I still got the eror production it's not getting the value I think it is not finding the env. development file so there was an issue it is not loading the EnV from the env. development. env. production if we will have simple. EnV then EnV package can get variables from the file but right now it is not getting it so you have to provide the custom path I just did a little bit configuration we have to import the path we have import the part so we have to use this syntax require this one all I have to do is provide the EnV path now it should work it should get the values so I'm going to create the migration cannot read property PA is equals to path but I got still undefined let's log EnV path oh it is getting the value from DB but my file is located at root folder so it is not here inside the DB if I try this one I tried to work with this env. production with custom path but it is not working all I did if I change EnV it is it will work let's let me show you get rid of everything now if I copy that and create EnV file in the root directory it will work I found there is an issue with type orm now I'm going to paste my code for production you you have to adjust nestjs build when you try to run the migration you have to update the changes here I found this is the way you can implement it but there was an issue with custom file path so now it will work I'm going to run the migration now I can see production and the my container name which is my DB host and my password now migrations has been generated successfully it's time to run the migration we got to run this command npm run migration run should be run you can see that it is running all the queries creating tables in the railway postris database now you can understand you can use this EnV for type orm build use it for type or RM migrations because in the app module we are using the configuration of config module we are not loading this EnV file we are loading envir environment development env. production file but you can use this EnV for migrations now we need to double check it we have to deply our code now it will take some time to redeploy the application the application is running now I got this secret key the database host and the password now we're going to run it/ API open this Swagger tool you can also double check it from postris database I have only migration table it should give me all the tables but something went wrong here inside the migration the record is empty table is empty unique key primary key what is going on oh I have two migr ations get rid of this file get rid of all these migrations let's generate the migrations from the scratch I'm going to name it to in it now migration has R it successfully I'm going to comment this code now you have to run the migration everything is good to go all the ques has have executed now you should see the data in the data datase you can see I got artist playlist songs and users table we have these columns if you want you can run the seed from App module I think we we were doing seeding in main.ts file you can enable this code application is running now let's create a new user amazing we have created the record successfully you can also double check it from the post database you will have the user here but I created this user from the this one from seeding because I think my seeds are running constantly I think I enable that seed in the app module we got to disable it otherwise it will generate more users I'm going to remove them now you have to see constantly a new data I can say disabled seats now it is going to redeploy the application so this is how you can deploy nestjs application to railway in this module I'm going to teach you how to do unit testing integration testing and end to end testing for nestjs application before getting started on testing I want to teach you some of the basics of just because we're going to write a lot of mock functions we're going to write we're going to write a lot of spying spy functions you will learn how to create Mo implementation of service of a controller of a repository if you know the basics of justest if you know mo functions if you know spy function then you can skip these three lessons if you want to refresh the knowledge of just you can continue this video just as you if you don't know about just just is a popular JavaScript framework it is developed by Facebook you can use for testing JavaScript application you can use just with react view angular and nodejs these are all the function alties of the Gest asynchronous testing code coverage snapshot testing moing and spying we're going to use a lot of moking and spine with nestjs that's why I want to teach you these two concepts in more details you will learn how to do matches and test suits and test running and assertion uh before creating the just project I want you to open an empty folder we're going to start it from the scratch and you got to create package.json file I can say npm in it d-s please create the package.json file for me I got the package.json file now I'm going to copy that and let me replace that here what I want to say we we need to install the typing of the justest we need to install the justest app a Dev dependency and I created the script to test the justest if you want to run the justest in watch mode I'll teach you how to do that you got to run you got to run this script so uh please install these two dependencies I'm going to install them it's going to install the dependencies let's create a new file I I'm going to name it to some .js file we're going to test this function we're going to write test cases to test this function in the third step we have to create some. test.js file I'm not using typescript here I just want to show you the basics that's why I want to keep it more simple we have to import the sum function from the sum. JS file I have to write the test case at 1 + 2 = 3 now we're going to write the test case you can use the test it should give me the result 1 + 2 = 3 so we're going to call this function it's going to take the call back function I can say expect it's not giving me suggestion because it is taking too much time to install the dependencies because I think my internet connection is slow right now so we need a function sum. 2 B 3 we have to call that function it is going to take two arguments if you look at the sum. JS file you will see two arguments A and B the first argument I'm going to provide one and the second argument I'm going to provide two let's try to test it out it's still working npmi minus TJ my both packages have installed just in the typing of the just now you can write the test case I've written the test case you can run it npm run test I would like to run it in the watch mode dash dash watch is not sported so you have to write the watch all now you can see that I have to update the script for the watch all now we have to select the pattern I would like to run this s test.ts file right now we have only single file it's going to execute this file the test has passed now if I write the invalid value I save the changes it has started automatically and I got the error expected four but received three you can play you can play around with multiple matches function let's say 1 + 4 or to have been called to have property to have returned to have returned with let's say five you can play around with multiple watches received have as type number so this is not a right matcher function so I can say it should be five this is how you will write your first test case now I'm going to teach you the concept of mocking we're going to play around with mock functions Auto mocking inest refers to the automatic creation of mock implementation for imported modules or dependencies during testing let's create the mock functions you can use the mock function to track the function calls if you want to remove the dependencies we're going to do in njs testing we're going to remove maybe the implementation of service implementation of the service then we will have more implementation we can simplify the testing and control behavior when you do the unit test your code let's say if your code is dependent on five dependencies let's say if your class is dependent on on Class B Class B Class C or class D let's say and you want to do the unit testing let's say this is the class A now Class A is dependent on let's suppose Class B Class C and class D now Class A let's suppose we has two function or one function if you if I want to test the one function from the class A when you do the unit testing you test the individual Parts you test the individual functions to test the individual function maybe the individual function of Class A is dependent on the function of Class B function of Class C and the function of Class D then we have to write the mock implementation for the class B Class C and the class D I'll teach you in the later videos now we're going to create mock function this is how you will describe or you can group all your test cases into a group describe I want to write all the mo function examples in this section it is similar to the test you can Define the it or the test it is referring as a test so it should create the basic mock function let's create a new file Mo function. spc. TS file I have created the test.js file but you can also create the spec. JS file the concept is same now now we have to write the mo function here I can say I will provide the mo write Mo function examples here this this this section will have the mo function examples let's write our first test case it should create a basic Mo function should create a basic mock function you can create a mock function by using the just. function I can say this is the mock function just provide is a FN now we have the empty Mo function if you log the mo function you will see this is the empty function let's try to do it run the script again to run the Tex test in the watch mode this time I'm going to add the pattern for the more Dash function. spc. file it is going to ask me the pattern I can say mock now it's going to run this file if you see the log you have a function a mo function if I call that you will see there is nothing here we have undefined function if you pass the argument it is going to still it is going to still give me the undefined this is the empty mooch function if you want to return the value from the mock function you can also do that return value Mo return value now let's say I I would like to return the four now if I call that function it should give me the value of four I can write the match functions on it mock I call the function to be the value should be four you can see our test has passed now if I add the invalid value which is three it's going to give me the error expected three but received four if you want to remember I told you you can also keep track the calls of the function with the help of Mo how many times this function has cost called mo. calls. length to be we have called only one time so it should give me the length is one if I call the function two times Mo function dot to have been called been called let's say I want to call that function and I'm expecting the four it should give me the error you can see that the save to expected is one here we have the error it should give me the two because we have called this function two times if you want to keep track of the calls of the function how many function have how many times you have called the function you can also do measure on that here I can say expect mock function to have been called it is checking that did you call the function yes we already called two times this is how you you can return the value from the mock function you can create you have learned how to create the basic mock function now you're going to learn how to create a basic Mo function with arguments we did not create a function with argument we just created a basic mock function then we have returned the value here I can say it should create a mock function with an argument let's create a function con mock song function you can say song mock just. function it can have create song dto let's say that mock create song and this function will have this argument but I also want to write the implementation you can do that as well well right now we did not return the value if you want to return the value you can do this stuff it is going to return a song title animals and ID or you can oh animals and ID which is one let's say that that if I am expecting on that it should give me the same object animals ID which is two or ID which is one if you want to test the object you can use this two equal expression make sure you have called that function with argument create D is not defined title should be animals create D is not defined I think it will not not work we have to write the implementation here I just want to show you the another alternative path it's a call back function it's going to it's going to return the create song dto now you can look at this one now my test has passed now if I will write the ID it should give me the false it should give me the false value or it has failed because I am just returning the ID but you can pass this test if I create if I return the object use the spread operator and ID which is one let's try to check it out out now my function has my test has passed now if I provide the another value lower in our application this function like create song function does not exist here we don't have a create song function we don't have njs project we don't have repository we don't have service controller that's why this is how you can create the mock implementation you can also create a mock function with mock implementation we used callback function here here but if you want to use this Mo implementation you can do that as well it should create a mock function with an argument with Mo implementation this one I don't have preer file R see single C to true because I use this prettier formatter now my code has formatted now we're going to use the same approach const mock create song just. function I have defined the function mock create song do mock implementation create song dto it's going to return the object create song dto and the ID which is one now I'm going to ex run the mat to test the code my code has passed now my test has passed now you can approach you can implement the same stuff by using the call back function here or if you prefer the mug implementation you can do in this way now I'm going to teach you how to create a mo function and it function this function should return the promise all you need to do is call the mo result value we use the mo return value you can do that with the help of Mo resolved value let's say I would like to create a new function let's create a new test case it should create a mo function with promise ultimately it it is ultimately it is going to return the promise fetch song data or you can say that fetch all the songs from the DB or you can say the network request now we got a return Mo return or Mo resolved value let's say fetch songs I got the array ID one title Lover now I will like to call that fetch songs Doc do results dot to equal if you want to apply assertion on promises you can call the results property and then I can apply this Expressions to equal this one make sure you could to call that function now my test has passed if I write fetch I'm going to call the fetch functions do resolves dot to have length it should have one my test has passed if I write the two it should give me the error because we have only one property in the songs array I got the error I'm going to call it with one this is how you will do the mocking you have learned the feature Auto moing which is mock functions but we did not talk about the spank and you can control the behavior and you can assert on their usage during testing you can create the function spying on spy you can spy on a function by using the just. spy on it allows you to create a spy or a mock function for an existing object method if you want to spy on existing object you can do that if you want to spy on existing class you can do that now we're going to spy on an object we have an object spy on a method on the object we going to Let's imagine we will have the song repository and we have the create method what I want to do I want to spy on the create method I don't want to use this implementation I want to use my fake implementation in under the hood just will tell you you I called this function but I have used your implementation this implementation this one instead of instead of using this original implementation let's spy on I want to I want you to create a new file since by on demo dopc dots let's create a song repository and we have a create function let's imagine we have a find function let's imagine we have the find one function I want you to add the add this Pi on this find find and find one but first let me do that find one will accept the ID let's imagine the ID now let's create a function so I created the test case it should spy on the existing method function object method so you can create a function on this py on so this is how you will spy on the function it should also give me the toll tip create if I log this piy function let me show you what is inside that I have to run this file P I want to spy on it's going to run this file my test has passed but this is a mo function if I call that it should give me nothing because it's an undefined what what if I call the function SP and I'm going to call it not an ID let's provide the title or let's say if I call the function function of this song repository you will see the magic I have called this function now my function this function is pying on this function what will happen if I log spy do mock do calls it should say I have been called with this argument array it's an array mo. length which should be one it is saying I've been called only one time by using this one if I call song repository. create let's say title new song now the length should be two you can see that if you want you can spy on the function spy do to have been called now my function has been called expect spy you can also say that to have been called called with called with title should be lower it is fine now if I say lovers it should give me the error you can see I got the error you can also track the how many times this function has called to have been being call times it's going to give me the one I'm spying on this function song repository. create similarly you can spy on the find and the find one you can also spy on a class I'm going to create a new class we have let's say I'm going to place the Clause here we have safe method in the artist repository I want to spy on this function but you can also write the implementation just like we did it we can have our own custom implementation I call this method now you can see that to have been called times to have been called with at the end you can also restore the mo but I would like to do this one after each please restore all the mocks this is a hook after each it is going to run after all the test in this section in describe section now we're going to copy that test case and paste it here we have created a new instance from the artist repository and I call just. spy on I want to spy on the save function but I also want to add my implementation it is going to return the create artist dto or it is going to return you can say that I would like to return the object create artist dto and I want to add the ID now you can see that spy it is going to call this function artist. save what is here I called spy name and it has returned Martin Garrick and with ID which is one and how many times to have been called yes expector to have been called with name we provided the Martin garx spy and I don't need to do that because we are doing it here expect spym do calls. length how many times have you been called I think I did it one time rt. everything is to have been hold with two times also called artist. save and I also called it manually now it looks good in this lesson I'm going to teach you the concept of unit testing in nestjs when you do unit testing you test the individual component of your application individual component means individual function of a controller of a repository of a service we have song song service I have attached this started kit project you have to open it and run npm install you got to install all the dependencies we have uh we have this song controller when I'll be talking about unit testing I mean I have to test individually this function get song get songs create song and update song and delete song but you notice the song controller is dependent on song service here we need more implementation of song service because I want to test individually this song controller but when we will do end to end or integration testing when you will test the end to end you will integrate all of your services all of your classes all of your dependencies you can verify your unit of code such as fun s methods or classes with the help of unit test you can find the bugs earlier you can improve the code quality you can do faster debugging you can refactor all refactor code very easily now when you run the source code when you run the test for song control dopc file nestjs already created this spec file for us if you run that it is going to say hey when I look at the song controller I saw dependency There song service but when you are creating the testing module here we are creating the testing module on the Fly n sjs will compile it when it will comp compile it will instantiate all the dependencies for the testing module here it is saying I'm depending I'm dependent on song service but you are not providing any song service here you not providing any provider let's say you are not any provider song service so it will give me the error because we are doing unit testing I don't want to include song service here I want to test individually these components but I'll teach you how to fake how to create the fake implementation of song service here we are getting the controller from this module and it should be defined this is the first test NP you can run the test they have created the script for testing I'm going to use this one npm run test watch let me provide the pattern for song controller dopc now it is going to watch this spec file you can see that test has failed now here have you included song service in the provider no we no we did not if I will add the song service but still getting the error now the song service is dependent on the song repository but we will include all these dependencies in integration testing but I want to test the individual components so get rid of the song service I got the error so we need a fake implementation we got to create the mo service for the song Here is how you can register a mock service with the help of Mo implementation you have to register the song service and you going to provide the song service provider here you have to use the use value property to create the fake implementation object or the service you will have the get songs method inside the song service here I created the mo function and it is going to return the promise with this record let's try to check it out when I will open the song service we H we will have these methods get song is returning a promise get song is also you have to write the fake implementation or Mo implementation of the song service we need providers song service song service here we have to write the fake implementation get songs you can create a mock function all you need to do is return a promise with a value let's say ID is one title title let me check the song model or song entity we have one property which is title dancing feed now I have the mock implementation of get songs now you can write the test case make sure you get the service if you need I think I don't need that you can see that now my test has past now I'm going to write another test case it should it should fetch all the songs or you can wrap your code inside the describe fetch all the songs here I have to write this one or you can say if you need to write multiple test cases for get songs functionality you have to do it in this block now we have to call the function songs v controller. get songs it's going to call this method get songs you have to use the async keyword now we have to write the matcher it is going to give me the array of the songs to equal now we're going to copy this one a test has passed now get song should fetch all the songs now I'm going to copy all of the code for mock implementation for the methods of controllers it should add the create song dto it should have the update song dto what we have done so far I created the mo function with Mo implementation remember it is get it is getting the idea is an argument now it's going to return the promise here for the create song it is accepting the create song dto I create the ID which is a unique key and I have separate the separate the create Song D it's returning a promise similarly we have done for the update song we created the mock function with an argument update song dto returning the promise in song service for the update it is returning the update result so make sure you have this affected one and delete song what is an error oh I have to restart the project now we have a fake implementation of delete song now let's test this function get song by ID I'm going to copy that get song by ID you can provide an ID which should be anything get song Yes ID could be anything or I I can provide a unique key a uu ID you can see the test has pass now for get song ID now I'm going to copy the create song Let's test it we have created the new new song by using Create song dto we have to provide this create song dto and song. title should be run away because we are giving this argument here create function is giving me the create song dto with ID or you can also write another matcher to equal ID should be a uu ID ID and title should be Runway run away you can see that my test has passed now similarly we have to do the same thing for update song we are creating the update song dtoo by using the update song dto object I would like to update the title it should be defined and affected should be one update song you can see update song has passed now now we have to perform testing for delete song I just provided the ID you can provide any ID you can see that delete song has also passed now this is how you will test your controller unit testing for controller in this lesson we're going to test our service we're going to write unit test for service when you run this service you will get the same error because in this song service we have a one dependency which is repository the song Repository we have these so repository will have this we have to write the mo implementation for find method find one or fail save method and create method update and the delete because our service is using these methods from the song repository so if you write the if you run the test for song service. speec you will get the same issue this is the default implementation from nestjs Project they are using the provider right now we don't need any controller here we are doing unit testing we are doing individual testing for each function let's run the song service it is going to find the song service. spc. TS file the test has failed now it is dependent on the song repository but I did not provide here I did not register it so we have to create the fake or Mo implementation for song Repository what I'm going to do I'm going to copy this code we need these get repository and get song I have created a two objects song array song one song song and the song array this is how you will create the mo implementation for the repository we have to get the repository token here I can do that one thing make sure you provide the song service I forgot to do that in the controller Let's test it so everything is working fine now now we're going to test the service we have to import it get repository token I'm telling to nestjs this is my fake or Mo implementation for the repository song service for the find it is going to return the array we use promise. resolve Mo implementation for the just I'm getting the options as a find one options you can import it from the type orm we also need to import create song dto it is returning a promise with one song it is going to return the promise with a song newly created song and save method is just a simple Mo function it's not doing anything in update we need to get update song dto we have return the mo implementation and it is returning a promise with one song for the delete it is returning a promise with affected but maybe for the update you can give this response affected one now we have to test it if you need a repo you can get the repo yes we may need a repo I can get the repository by using get repository token let's test the method from the song service it should give me this song by ID we're going to test this method this one this one get song by ID this one it is using find one or fail and is using fetching the song on the based on ID so what I have I have done I created a new song I I got the song on the based on ID it should be Yu ID Yu ID so I'm going to spy on this find one or fail what I have done I called this method get song in under the hood this Pi this method this Pi just Pi will be spy on find one or fail it is saying hey you have called find one or fail from the original repository method and it has been called with this one this is how you can write the unit test now we're going to write the test case to create song I created this song and I'm going to expect it with one song called one time and you can say called with title lover let's copy the update let's copy the delete everything is passed now for update I think inside the song service what we have done update result so we have to fix it more repository it should give me the affected and the one result result do affected equals to affected one test has passed now if you want to spy on delete method how many times I have call delete method if you want to track the calls you can spy on that by using the Spy repository on delete method I've have been called this one time and it is affected one time I got the it means affected means one record has deleted successfully and it has been called with uid that's all for unit testing with service now you're going to learn the concept of end to end testing we're going to do end to end testing for our nextjs project end to end testing is a software testing methodology that focus on testing the entire application flow from start to finish now we're going to integrate all the song controller repository song service everything you can do API testing in end to endend testing validation of the user flow improved user experience now we're going to start doing the end to end testing first step we have to add the script in our package.json file they have written the script for end to endend testing but they did not add add the watch that's why I just addit the watch or detect open handle I I have written this line or keyword for to handle the errors if you will not at this line This one this word it will give you some type of warning messages the first step we have to register it the type or a module in the song and to end test here we have the end to end test this one this is the end to endend test for our generic application let's run it npm run test find the script test E2 e and the watch mode let's provide the pattern app it is going to run this spec file this is end to endend testing for app module going to create nests application and initialize it here it is going to test our root URL under the hood they are using the Super Test request from the Super Test making the API request by using calling the server this is the end point and it is expecting the 200 status code test has failed got expected 200 but got 4 44 but I would like to add the test case into to end testing for our song controller for song module let's create a new file here inside the test I'm going to name it to songs I can call it songs do E2 do- spec. DS file it is just an initial code you can copy that from the app do e2e testing I got this one describe it should be songs import couple of dependencies type or module make sure you have created the database for testing I created that with the test F and syn synchronize set to true you have to register entity manually it will not work with regular expression at the end of each or at the end of all test when all the test will be finished it is going to drop the schema we will have the song Mar is not getting the path I think so we have to do in This Way song Find song entity same thing here there is I got the testing modu that's it now we have to run it here you have to provide your username password and the Local Host Post Port in the name of your TP it is going to run this file I got the error you your test Suite must contain at least one test all right now we're going to test the code first step after each test we have to clear the repository because we're going to interact with database in the describe this will be run before all and we will have after each we have to clear everything from the song table or song repository this clear method will delete the records from the table but it will keep the schema schema this function or this hook will run after every test make sure you import the super test I'm going to write the test case for delete or not not a delete for create I just created a new method create song we have the song song. title song. repository and it is going to save the song in the real database right now we don't have more implementation for the song repository or the song service it is going to save the record in our real database we are using the test def if you don't have test def you can create it I have set the title get the repository instance from the app.get and called the safe method maybe you need to add a weight expression because we are returning a song with promise you can do in this way it will automatically get this promise with song let's write the test case before fetching these songs make sure you have the record in the database that is why that is why I created a new song with create song first you got to save the song in the in the postest database with title animals and then you have to send the API request to this URL doget and here I'm checking the status code should be 200 and the request body or the results body should have length one which should be have one record it is an array it is going to give me the array in results. party and I'm I have created a one song so it should be there there should be one song in our database so that's why I converted into an array after then when this test will be completed it is going to call this method clear the repository you can see our test has passed now if I write let's say 20 1 or maybe 400 it is going to give me the error hey I'm expecting 200 you can see I got the error so get song endpoints has tested successfully now we're going to get test get song by ID first we have to create a new song then I have to I have to send the API request make sure you have to send the ID I created this song because after each test it is going to clear the repository it is going to delete all the records from the songs table create a song then it's going to you have to provide the ID first I have created the song then we have to test it make sure the body should equal to this song I'm going to save the application it should pass two test has passed now now we're going to test update songs endpoint make sure you have to import it it should be it create a new song and you have update song dto I would like to update the animals to wonderful sending the API request this is how you will send the data to if you want to send the Json op object into the request body you can call the send method I want to send it as a update song dto this one I want to update the title which is wonderful status code should be 200 and affected should be one it means our record has updated successfully and let's do this for post we have this is our create song dto we did not create we did not create the song right now I'm going to use the create song dto provide it as a request body the status code should be 2011 and the title should be animals for test has passed now we have to test the delete song endpoint let's create the song first and then we have to provide the ID which record you want to delete status should be 200 and the affected body should be affected should be one it means record has deleted successfully this is how you will write the end to endend or integration testing with database or the nestjs application nestjs version 10 has released now I'm going to show you how to create new projects with nestjs version 10 version 10 is very fast they have integrated the rest rust compiler they have integrate the rest to compile the source code sjs if you Google the version 10 you will find the blog post from the owner of the nestjs they have released version 10 in the version 10 you you can compile the code in a faster way like it will also improve the hot reloading you can you can do development in the more fast way to start a project you have to add this command we we're going to use this options this one we will add these options into Nest CLI they have also introduced a new feature this time you can Mo the entire module instead of provider and controller these are all the new features in the nestjs version 10 but the main feature is improving the compile code speed of the compiler but let's create a new project first of all you have to remove or uninstall nest jli because you will have have the older version of n CLI I'm using Mac so we need to add the sudo keyword instead of install first we need to uninstall the nli I have already installed nli can I check the version of this package I don't know let's try to look at that I have 8.1.0 I have I have the latest version but it will generate the nestjs 10 project Nest new and we have to provide the name of our project I can say web socket implementation nextest let's do it again nextest new the name of the project websocket implementation I would like to use the npm it will take some time to install these dependencies my project has created I can look at by going to this directory I would like to open this project into my vs code editor if you check the package. jsn file you can see we have the nest version 10 now what I have to what I have to do we have to compile the code faster let's first we have to run the project without this command This One S swc Speedy web compiler first we have to run it without Speedy web compiler you can look at the time for running the project when you will have multiple modules you will have multiple controllers and you added the testing functionality your application speed time will be slower your development time will will be slow so let's make it faster with the help of these two options I want you to add these options into package into nli n c. Json I'm going to add these two options to my compiler these two options Builder I would like to use the S swc and type check let's run the project you can see that I got the issue fail to load fail to load s swc CLI and S swc core we got to install these two packages let me execute this command install it as a def dependency because I want to improve the project running time increase the development time so packages have installed now we need to run the project now it can take the S swc it can use this Builder and type check our project is running the project running time has increased now if I save something in our application let's say in the app controller in the app service hello world from nestjs version 10 I want to save the application successfully compiled this is how this is how you can improve this implement or in improve the development time the project running time in development environment in this module we're going to work with web sockets when you want to implement real to real time application like chat web application real time web analytics live streaming online gaming then you need web socket which we have worked with HTTP server in HTTP where client sends the request in the server response but if you if you're using web sockets web sockets establish a persistent connection between client and the server and you can have ongoing communication the best example is Facebook Messenger you send a message to your friend and your friend rep replies and you reply to your friend and your friend reply this is how the bir directional communication Works in under the hood they have implemented the websocket protocol they are using the websocket technology if you need to make persistant connection then you need websocket you want to implement a realtime feature like live updates live score live streaming then you need websocket here is chat application can be built with web socket collaborative editing tools real time analytics online gaming and the live streaming nestjs also provides websocket module you can use that but it also provide two approaches you want to do you want to work with socket iio or you want to use the web socket you can get the details from their official documentation but in this video I'm going to implement the socket IO you got to install these two packages I'm going to open my package.json file let me add my dependencies I think I already installed these two dependencies I don't need to do it again you can do it manually by running npm install and first install this dependency and then you have have to install these dependencies our next step is to create the events module we will have the Gateway a Gateway will be responsible for handling the events you will have the events module a Gateway is nothing more it's a class with provider you can inject it as a provider here we we need this Gateway we're going to create the event Gateway it's nothing more it's a class here you have to decorate with websocket Gateway I'm allowing any origin you can use any specific origin if you want here I'm trying to implement the own module in it when any client connected to my application this event will be triggered this is how you will register the event by using the own own function I can also get the socket ID I can also log that have has it connected or not this is how you will create or register a new event subscribe message and we will have a function new message you will have the message body you will get the data if someone sends message or filed an event from the client side application like react angular view or any kind of front- end application this function will be called but make sure they have called this event with message key this key and it is going to lock the data you can read this text here for every detail let's create events module we have created the events module now let's create the Gateway you can see we have the events module Gateway will be registered as a provider you can see in the events module we have websocket Gateway by using this decorator and we have one event if you want you can add the CES and we also need to establish a connection I need to check make sure you imported server from socket IO Library you have to import it manually otherwise it will not work websocket G websocket server now we have this handle message subscribe message when you need to register an event in backend application or the nestjs application you will use the Subscribe message decorator and what I would like to do I want to get the data or you can have client but I like the data I don't have any payload option but I'll use the message body decorator instead of use this one message body data should be type any I'm not going to return any thing right now all I want to log the message I can say message received from the client and this is my message or I can log the data so far we have registered the event when any web application like any front-end application has connected to our websocket server first they need to connect on the our host here we have provided but right now we're going to run the project on Local Host so any front end application should connect with Local Host colon 3000 and then he can establish a connection between with with this application when when any front end application establish the connection it's going to call the own module in it but right now I don't have any own module in it right now it will log this message implements on module in it that's it after module loaded or this file is this class is loaded successfully then we can log the message when connection established this event will be triggered and it is going to call with socket I ID and the connected its Boolean value now we have set of the websocket server and we created our first event which is message you can have multiple events here you can also perform the DB operation like if someone sends a message you can save the message into database in the next video in the next lesson we're going to consume this event from our frontend application we will have a simple basic front end application with index.html and there would be JavaScript in the index.html file now it's time to consume the application consume the event or send message from the frontend application when you run your server let's say npm Run start def now my server is it's ready to listen this message event it's waiting for someone to send a message by using this event key so all you need to do you got to create a basic index.html file you can copy that code or you can create manually I can say client here I will have index.html file one more thing you will see events Gateway subscribed to the message event to this message so it means we successfully created the event I'm going to copy the code I'm using the socket IO Library where we are creating the socket IO instance by providing our application path in our case we have nest's application is running on Port 3000 we have registered a event it's trying to connect with our application with nestjs application when it when it will be connected it is going to log this message and emit this message to the server here I'm going to open the server this one events Gateway we have registered the message event this is how you can emit the event I'm telling to socket IO please call this function that's it and we also registered couple of events if someone if if server sends data back to the client we have to register it we have to catch the data here that's why I use the on listener if exception event trigger it is going to call this method if if our backend application disconnected or stopped it is going to call this event it is going to trigger this event now we right now we're not returning anything here let's try to test it uh I'm going to use open Live server go live when you open the index.html you will see this it is going to open my project into live server please check the console for message reply inside the console you will see you have connected successfully when you open your backend application this message is received from the client so client has sent this message or you can say I am the client I'm going to reload the application it has automatically reload reloaded you can see I'm the client so it has also connected one more thing you will also see this socket ID and it has it means connected successfully first it is going to log this message console. ID Lo connected we have emitted this message event it's going to call this function now we we are not returning anything that's why this event is not triggered let's try to return from return something I'm going to return some value let's say some value from server let's see what will happen our application reloaded let's try to test it out message received from the client but I did not log what message have you received you can see message received from the client on the client side we sent this message I'm the client it has received but it is not triggering this event I cannot see anything here let's say if I if I'll try to log something hello I cannot see this Hello message in my console it's not triggering so that is why you need observable websocket also provides the observable you can say I would like to return this observable websocket response and I can have any type here we have to convert the object to observable that's why I'm going to use the off operator from rxjs I can say event you got to provide the name of the event which is message and the data here you can return anything from the server message returned from server hello you should see this message here because we are listening on the client side you can see event message received from the server if I will refresh our application you will see this one message returned from the server hello if I stopped my application it is going to F this or trigger this disconnect event you should see the disconnected this is how you will create wi directional or realtime chat application with web socket in this lesson I'm going to teach you how to set up graphql server we're going to use Apollo server nestjs Apollo package nestjs graphql package graphql and TS Mor you can read the documentation of these packages I'm assuming you must know the basics of graph ql I'm not going to teach you the basics of graphql what is graphql and why do we need graph Q I have attached a started kit project you have to open it and run npm install I have already I have already installed all these dependencies I don't need to install them again all I need to do is to install graphql packages I'm going to copy all of these packages the packages have installed successfully and now the next step we have to register the graphql module I'm going to open my app module and we I would like to import graph module here we need to import couple of dependencies Apollo driver config I'm telling graphql hey I want to use Apollo driver and I will have do graphql file where I will place all my schema definitions in the graphql file this file will have the typescript typings of graphql and output as a class don't worry I'll Teach You How can you generate the typings we are using for RO to register the graphql module the Apollo driver config specify the type of the configuration options being provided so driver AP poo driver this property sets the driver used by the graphql module in this case we are telling graph Nest chairs hey I want to use a polo driver we will place all of our graphql schema in graphql file the extension should be do graphql uh if you want to generate typescript definition from your graphql schema you have to specify these definitions I'll teach you how to do that and we are just combining the path we will have so graph. TS file inside the source directory this property specified that the generated type script definition should be outputed as a class this means that the generated code will be representing represent the types as typescript classes now our next step is to create a schema file inside the song folder I'm going to create a new file song. graphql here I will place all of my schema file we're going to have a query let's define a song type we will have ID and the type of ID is required this means it is a required property it should not be null and I'm going to add a string variable or string type field which is title the type of the title is string and I'm also going to add a new query type here I can say I want to fetch all the songs and you can say the type should be song and it is going to return all the songs our next step is to generate the typings which is typescript definition file we need a graphql definition Factory class here we are trying to in we are instantiating or creating a new object from graph definition Factory there is a generate method to generate the typing you have to specify the type which is I'm using the regular expression here I will have all of my schema file in the cql that's why I use the type definition path and I would like to I would like to create all the type typescript definition in the graphql dots file it will save it as a class let's create a new file generate typings dots file inside the root directory typings dots now all you need to do is to execute this command NPS npx DS node generate typings it is going to generate the graphql dots file with this definition you can see that a graphql dots file has created we have a class which is song and we have a abstract type which is I query and we have this type so we will use this type definition when we will creating disolver functions when we will resolve queries against your schema files now I would like to run the application is everything fine now let's test it my application is running now let's send the request to Local Host colon 3000 and you will have playground at this graph quel Endo when you go to the Local Host colon 3000 you will see the playground this is how you will perform graphql apis you will test graphql apis by using this playground let's say I'm going to send the API request graphical API request I want to fetch all the songs I want to see the ID and the title but it is going to give me the error hey you don't you are not resolving this query because it's returning n it's getting the validation eror because we don't have any resolver to resolve this query this one in the next video I'll teach you how to create mutations and how to create queries we're going to we're going to fill our song schema let's complete our schema let's create a new query to fetch a single song when you try to fetch a single song you must need to provide the ID so ID should not be null and it should return this song in the response let's write a new query it should give me the song and I would like to fetch the the song on the based on id id should not be null now we're going to write uh venue query in the playground you got to follow the structure song and you have to provide the ID in this case I'm providing the 1 2 3 as an ID now we're going to Define mutations we learned how to fetch data with the help of query but I want to write the data so to to mutate the data you need a mutation so let's define an mut mutation mutation I'm going to have create song it will accept the create song input or create song input and I don't have any type so that's why I'm going to define the input create song input I will have the title field and the type should be string it should not be null so I can say the type of create song input it should be create song input and it should not be null and it should give me the song in the response now I want to write the mutation for delete song or you can say update song I would like to update the song Only the based on ID the first argument it should be ID and the update song input we will have update song input it should give me the update result this is not an empty field that's why I use this exclamation mark and input update song input title should be string but I did not mention it to required property if you will have multiple song multiple fields in song let's say a user will have let's say a song can have date or you can say date release date or publish date or artist something like that but I cannot set date required in the artist required field because it depends on the user a user can update the title or whatever he wants to upate update now I don't have any type for update result let's define a new type update result it will have affected and type should be number do we have int yes int similarly we will have a type for delete result delete result and typ should be int now we're going to Define mutation for delete song I can delete on the based on ID here I can say delete song I don't need to put anything and it should give me the delete result that's it so we did not resolve these queries in mutations in the next video we're going to write resolver functions to resolve these query and mutations Let's test it out by generating the type one more thing I want to show you can create a script to run the typings I can say in the package.json file let's define a new script we here you need to define the script generate slash colon typings TS node generate typings this njs project all already installed TS node as a def dependency you don't need to install it again npm run I can say generate typings it will generate the typings or types in the graphql dots file I found an error unknown type create song input did you mean create song input or update song input oops I have to fix that everything is fine now let me see my graphql dots file we have type for create song input type for update song input we have types for mutations and update result and delete result when you see your playground you have to look at the queries in mutations we have queries and mutation when you try to fetch let's say I want a query for songs ID let's say I'm going to provide invalid ID let's try to fetch the title and the ID I'm going to send the request it should give me the error hey you are not resolving that's why we need resolver I can use n CLI to generate a new resolver I can say song it's going to create a new resolver resolver is nothing more it's a provider like a service you can inject it as a dependency here you can see that inside the providers we have a song resolver and it is it also created the song resolver dopc file and song resolver we have resolver Tator now I'm going to resolve these queries I'm going to open song do graphql let's resolve this query I also need song service so Constructor private song service song service let's import it I have this I need a query decorator here I would like to resolve this query songs I can say get songs return this do song service dot get songs and you can also mention your return type I can get it from the song entity or song graphql type this one make sure you are using the Asing here what is saying unable to resolve the signature of method decorator when called as an expression oh we need to get the query from nestjs Craft ql now it looks good let's try to test it out let's try to resolve this query I would like to fetch all the songs you can see that we have a song I already created a song If you don't want to see the title you can say I only want to see the ID but I have single song in my database now let's resolve the query to fetch a sing single song I Can Say song async Get song it should give me the song with promise this do song service dot get song you need to provide the ID but I can get the ID here I can use the arcs from the N graphql I can say the id id is string let's provide the ID here I have saved my application let's try to resolve this query I want to copy this ID and let's fetch a song ID should be this one and I'm expecting the title in the response fail to fetch please check your connection I think my application did not start it now I have to send the request I got my record which is song on the based on ID if I provide the invalid ID let's say you will see the error invalid input Syntax for the type the ID does not exist as same here now I'm going to provide the correct ID I got the record you have learned how to resolve queries in the next video I'll teach you how to resolve mutations now you're going to learn how to resolve mutations in the previous video we resolved our queries let's resolve these mutations create song update song and delete song now you need mutation instead of query we also need create song dto as An arcs or you can say create song input you can also do that you can also get this typing from from graphql file and I just called this function it's not finding source. cql we have to do it manually now it looks good it is taking some time to in restart the server let's create a new song I'm going to write mutation create song create song input we have to provide title the name of the song which is follow me I want to see ID and title in the response you can see a new song has created I can fetch all the songs and you can see follow me it means we successfully created this we have successfully resolved this create song mutation now it's time to resolve update song mutation I'm going to copy this one update song we need to Res solve we need to get update song input update song dto or you can use update song input from graphql file I also need to get update result from graphql it is saying I'm getting the error update song If I get this from from typ orm let's see what will happen now it looks good because this start update song it's returning the update result from type orm when you look at the update song you will see the Promise with update result I imported update result from typm let's try to update the song I'm going to write mutation update song we need the ID I'm going to copy this ID let's place it here and we we also need to provide update song input I would like to update the title update song Let's fetch all the songs and you can see the updated song similarly we need delete mutation let's resolve it I'm going to copy it here delete song we have to get it from the type orm let's try to delete this song mutation delete song we need to provide the ID I'm going to copy this ID let's see affected delete song successfully executed it should delete the song let's try to fetch the song on the based on this ID you will see there is no song here you can see there is no song in this lesson I'm going to teach you how to handle errors in graphql let's say I want to fetch all the songs but instead of returning all the songs I have to return the error you can do simp simply by using throwing the error or you can say let me do this in this way I'm going to comment this line through new error I can say unable to fetch songs let's try to send the graphical request it's still working my application did not reload yet let's wait now it has reloaded you can see unable to fetch the songs I got the error internal server error uh if you check the Apollo documentation we are using Apollo driver Apollo driver is saying you can use the graphql error class and you can provide your own message Apollo Apollo Apollo documentation is saying they also provide buil-in error codes like Parts field graphql validation field Pat user input bad request we're going to use this error bad request all you need to do is to throw the error and you going to provide your message in the code so let's use the throw the error new graphql error I got this graphql error class from graphql package here you can see that now first I have to say unable to fetch the songs you have to provide the options you can provide the code you can say server error or what what type of message you want to use it depends on your use case I can say internal server error let's try to test it out I saved the application it will take some time to in reload the application application has reloaded let's send the request and I got the error unable to f F the songs and I got internal server error this time you can see graphql error unable to fetch the songs you can also see the message I got the error at song resolver doget songs you can also check the error stack get song song song resolver doget song we have the error at this function get songs this is how you can send the error in graphql if you want to use your own custom message you can also do that you can provide your custom message your custom code and your custom extension you can also set the HTTP status if you're working with HTTP API you can also set your HTTP status code and some type of headers in this module you're going to learn how to apply authentication in graphic SQL we have implemented authentication with rest API now I would like to implement authenticate graph cuel apis in the previous module you learned how to create graphel apis with nestjs I'm going to pick the same example project just like we did with authentication in rest API I have provided the starter kit code you have to open it and run npm install when you install all these dependencies you can run the project and you will get this error let me run the project because there is no graphql file there is no graphql extension file when you open the app module you will see the graphql setup we have a graphql module I'm creating a graphql module by using the Apollo driver just like we did with in the previous module I'm using the context I'm just returning a simple request mapping the request into request it's nothing more I'll teach you more about when we will protect resolvers so I've already taught you all of these stuff like we created the OD service we have a login method here we have a JWT guard I taught you how can you do that what type of implementation we have done we have passport strategy with JWT it's validating the user and we have dto login dto everything everything I have taught to you if you don't know about all of these functionalities you can go back to the module number six on authentication you can watch the first four lessons on authentication or first three lessons on authenticating nestjs apis you will get the error no definition found no type definition word found because we don't have any graphql file I just did the graphql setup first of all we're going to set up our we're going to define the schema we don't have we don't have any schema what I want to do I want to do schema in O folder let's create o. graphql what we are going to do we're going to create the user type and we're going to Define query and we will have mutation for sign up mutation and we will have login mutation first of all let's define a user type the first argument is ID it should be required not null first name the type should be string I can get this value from the user entity you can open the user entity on the right hand side right side first name is required last name is also required and email is also required and password is also required so we need these properties these five properties I'm not going to play around with playlist something like that let's make it more simple we defined a user type now I'm going to define a mutation sign up it is going to take the signup input and the type should be signup input we did not create it yet it should be required and it is going to turn a user back in the response or sign up response we not we did not create this we did not create this signup response type now let's define a new type with signup input when you when you sign up we are telling you need to provide hey client you need to provide the first name you need to provide the last name you need to provide the email email is also required password is also required now let's define the sign up response sign up response what you want to send in this signup response you can send a simple email it depends on you I'm going to send a simple email now we're going to Define query we have a mutation let's define login query I can say login it is going to take login input inside the login input and it is going to return a login response we did not not have these type yet it's are required let's define an input I'm going to Define input here login input we need email type should be string we need password type should be string and we also need to Define login resp response I want to send the access token you can double check it from your OD service or user service we have a login in the login we are just returning the access token here you can see that access token the type is string we're going to follow the same convention the type is string it should be required we created the login mutation that that's it let's try to test it out by running the mutation or running the typing command npm run generate typings it is going to generate the typescript definition file typescript definition file has created you can see graphql do s file we have all of these typings we have created or defined our schema in the next video I'll teach you how to resolve queries and mutation we're going to work on sign up mutation first in the previous video we have created this sign up mutation now we need to resolve this signup mutation we don't have resolver inside the O module let's create a new resolver we have to provide the name which is O Au resolver has created you can check inside the Au module we have Au resolver we have spec file and we have Au resolver we have to resolve our signup mutation mutation which is sign up I'm going to open the autra ql here I want you to do it should be sign up user I'm going to define a new function and it is going to return a sign up response you can get the typing from graphql dots file and one more thing we need to inject service user service and OD service we need both of them user service and we need OD service we have a create method let's get the argument I can use the arcs we need to get sign up input and I can say sign up input you can also also get the type sign up input and I'm going to provide sign up input everything is fine now let's try to test this signup mutation I'm going to run my application my application has started and I got the error sign up defined in resolver but not in the schema oops there is a type typo Here sign up we have to generate the typing again npm run generate typings everything is up to date it is taking too much time because I'm using no nestjs Version 9 because I built this project in module number six by using the nestjs version 9 that is why it's very slow I have to oh let's restart it again my application has started I'm going to send request to the Local Host callon 3000 and/ graphql if you check the docs we have a sign up mutation let's create a new user first name make sure you have database in your postgress let's provide the last name let's provide the email let's provide the password I got the error because I did did not select any field here I would like to select the email because I can only access the email I think I already created a user with this email let's use new one there is an issue reading password let's try to check the error password is invalid why let's try to log sign up input what it is getting or do we have sign up function here inside the OD service do no we got to use the user service. create let me check in the Au controller what we are calling what we are using user service. create that is it I'm getting the undefined maybe there is an issue in autra Q let's check it out oh syn sying up input my God sign up input sync input sign up input let's run the project let's update the fix it sign up input we also need to update it here sign up input run the project Let's test it out by sending the request to create a new user sign up input we also need to update that we have created a new user a user has created successfully you can see that we got the object let's log in I want you to implement it I'm going to copy that we need to get the query from nestjs graphql package we also need to get login input and the login response we have a typo here aouc I need to run the typing again let's run the project let's try to send the login request I'm going to copy use email and the password I need to get the access token we have successfully logged in because I got the access token in the next video I'll teach you how to protect resolver we're going to create a new protected field which is profile only authenticate user can access this profile we have created all card this one JWT o card we have to use this o card into our resolver I'll teach you how to do that but I want you to think about how can we implement or how can we apply JWT off card we have completed the sign up and the login functionality let's say I want to protect resolvers when we were building the rest apis if you look at the app controller I can say this is the protected route only authenticated user can access the profile and here we also getting the user from the request object but you are thinking about how can we protect the resolver let's say I want to write a query profile and type should be profile we don't have any profile type let's create the profile type the type should be string the field should be string and here we have the user ID let's generate the typing when we resolve this query only authenticated user can access this profile we should not allow anyone to see other person or other people profile how can you do it when we were building the rest apis we use the JWT guard we have created this guard and we apply when we applied this JWT o card on our protected route just like we did in the app controller this is my protected route the profile route and I have applied the O card by using the use card JWT oard maybe you thinking how can we do into graph well I'm telling you I'm you you also need God you also need JWT o guard I want you to implement it you don't need to change anything in the JWT strategy because we were using the passport strategy if you are not sure if you don't know about how did I implement the passport strategy you can look up the Authentication section I think it's section number six or module number six or seven and then you can get the lesson for passport or jwd authentication it has generated the typings in the graphql dots we have the profile class now when we resolve this query I have to say hey this is protected route let's let me show you I'm going to run the project to access the protected route a user or client should or client must need to provide authentication token the user can get authentication token by executing or sending the login request and this login request gives the access token in the response let's wait for the application my application is running now let's send the request to the Local Host col 3000 /ql here you can provide the authorization HTTP header I'm going to send the login request I got the access token here you can access the profile route you have to provide the token here we did not write the resolver for the profile query let's resolve it inside the Au resolver let's resolve Au query or profile query get profile it is going to give the promise with profile and here is the question how can you access the profile or how can you access the current logged in user like we need to send current logged in user actually we need to send the user ID the current logged in user ID and his email we are returning the promise that is why I caught this issue let's return new promise and resolve return resolve this object I just created the fake promise to pass this test oh I have written the profile in the mutation let's change it to query restart the application now we're going to send the request it's still running now we're going to access the profile I caught the profile but only authenticated user can access this profile so we need to apply the O guard how can you do it let's create a new guard I'm going to copy that guard and create a new guard and I'm going to say gql oards here instead of JWT I can say graph o card and now we need to do a little bit logic we need to use the can activate function because in graph ql we need to get the execution context and we need handle request it is going to return a user and you can import authentication error when you look when you look at app module you will see this request I'm just mapping the request from req request here I got the request from the context here you can see that and I call the super Constructor by calling this execution context host because in graphel you need to get the request object from the context when you have if you have worked with graphql before each resolver will have four argument here you will have for argument parent I think root context value and info you can get the documentation from Apollo server resolver here you can see each resolver has four arguments parent ARS context value and info ARS you can see ARs and I'm going to log everything parent console. log ARS console. log context value and we also need to log the info let's see what is inside this this stuff but make sure you apply the guard use guards I can say graphql or guard now this route this resolver is protected it is secure now don't worry I'll teach you everything what is going on here let's send the request here you can see the log console there are a lot of stuff here parent is undefined there is no parent for this query ARS is an object but is but there is nothing inside the ARs there's a context value this is there is the request object and inside the request object you can find your user here is the user I found the user this is the this is the user this is the this object is current logged in user if you look at the jwd passport strategy here we are saving user ID and the email that's why I got the user ID and email what I can say I can only return context value do request. user I don't need to use the promise here it's just returning a simple profile I'm going to send the request this time I got the original user ID and the email let's sign up up a new user I'm going to create a new user Linda let's save the email now I got the user we have successfully sign up let's log in I got the access token now I can use this access token here I want to access the profile of this route or user wants to see this his profile I got this user now let's debug the application I'm going to put couple of break points here what is going on here let's look at I have already set up the VS code folder inside you have launch. Json file if you don't know how to debug the application let me teach you I've already taught you there is a script in the package. s file for the debug the application you can say npm start please start the project in debug mode my application is running in the debug mode now I can start the debugging by pressing on this attach button I've put couple of break points here now it has started I can debug my applic a I can also put breako here or here now we're going to send the request it has stopped at this o card and first of all it is going to run the can activate function we are using getting the graphql context by calling the create and here I got the context object and inside the context you can see we have the Handler function we have the ARs ARS property the first one is object and we have a request we have this request and we have field name which is graphql field which is profile you you can see the field noes this is how graph run under the H this is my string or the query graph request and here is the name something like that profile which is profile let's step over the code you will see the context inside the context we have OD context type graphql now I'm extracting the request object by calling the get context so I got the request inside the request you can see that this is the request we have this endpoint SLG graph ql this is the body we have the query and we have the variables let's jump to the next break point there is no error and there is a user you can see that and it is going to return the user now you can access the user inside the context parent is null which is undefined we don't have anything in the ARs now you have the context value you can also do debugging here context value dot request. user you can see I got the user and we have the info info is related to information related to query if you need to access the path parent type field name something like that schema then you can use the info validation error we have directives include skip deicated query type graphical object type we have the fields login profile all this information related to graphql schema and the query inside the info object now we are going to just return the current logged in user that's how the authentication Works under the hood in graphql if you need to implement realtime application you have to build a realtime functionality like chat application or notification type application then you use graphql subscription if you have worked with API rest apis we used websocket and socket iio for realtime application but we are building graph apis if you need realtime functionality then you need graphql subscription I'm going to build or Implement graphql subscriptions with nestjs Pro project first of all you have to install dependency graphql subscriptions and then we will install the subscription Handler just like query and mutation you need to define a new type subscription I have created this song created field it means when a new song is published to Spotify application this Spotify application will send the notification to all users we want to implement this feature when you define the type subscription we defined it here you have to write the resolver to resolve this field we need a pops up module from graphql subscriptions the package we have installed earlier here it is going to listen for song created event this resolver is listen for song created event here we are resolving this field song created when you run the application you should go to the Local Host colon 3000 /g graphql I'm going to run the subscription song created we have ID title I have started the subscription you will see the subscription is listening it's in the listening mode our next step is to publish this event when we will publish the event you have to send the payload which is a new song and I have created a new song Here we are publishing an event here it is going to now the subscription is already running here you can see and now it can receive it has received a new song if you want implement this subscription you can do it otherwise you can follow me I'm going to implement it you have to install package graphql subscription and we have to install the Handler in the app module install subscription Handler let's define a new type subscription in the song graphql I'm going to Define It Here song created it is going to return a new song now we need to resolve it resolve the song created field inside the song resolver we need to import psup at the top of our resolver you can import it from graphql subscriptions package now we're going to resolve this subscription song created I can do it here at the bottom we need to get subscription from nestjs graphql package let's try to import manually from cql subscriptions we need pups up let me run the application and then I will be able to start the subscription in the listening mode the pups sub Asing iterator we are telling to pups sub module or the ppup module is saying I'm listening for the song created event with this label this is an event I'm listening for an event with this label song created my application is running now let's run the subscription when you check the docs you will see subscription with song created I'm going to start the subscription song created when a new song will be published it is going to give me this record the song object now it is in the listening mode when we will create a new song it means when artist in real world Spotify application has published a new song Spotify application will send the notification of this song to all users new song I can say new song I need to get ID and the title a new song has created but I cannot see anything here because we did not publish the event when we will create when we will be creating a new song Here we have to publish this event this one song creat event so you can do it as well I'm going to copy my code and let's do it here this is how you can sent message to the event by using the song created label and we have provided the payload make sure you use the song created Property name otherwise it will not not work let's create a new song I have created a new song and it is saying I cannot could not connect to websocket endpoint please check if the endpoint URL is correct now it's in the listening mode mod created a new song now I have got a new song because we are publishing a new song and it has received it here let's say I can say new the name of the song you can choose any name I have created a new song or artist has published a new song at Spotify web application now the Spotify application has has sent the notification to all users who are subscribing to song created event that's it the concept of subscription in this module you're going to learn how to test graph apis we have already tested our rest apis we're going to use the same logic to test graphql apis we're going to do Mocking the same way just we did in the previous module when you see song resolver dopc file you will see this default code when you run the test by using this command npm run test you will get this error hey you are using a song resolver but your song resolver is dependent on song service you have to import it but we are doing unit testing so when you are doing unit testing you have to test individual parts of your code you have to test individual functions if this function is depend dependent on some other functions or some other dependency or some other classes or some other services you will create a Moog implementation of the dependency I've already taught you the Moog implementation when we will when we will be testing song controller this is how you will create the mo implementation of song service you we will have have these methods inside the song service in get song create song we are just creating the mo implementation I just copied this code from the song Ser song controller song controller spec file and I have updated the create song dto to create song input and update song dto to update song input and then you will test your functions if you want to test your get fet song Get song function inside the song resolver you can do that I'm applying the await expression on get song and I got the song here I'm doing expectation checking asserting or expecting value it will pass this is how you will test create song create song will be passed update song and the delete song Let's execute it or you want to execute by yourself I want you to do it let's select the song resolver it's going to run the song resolver dopc file you can see the error hey your resolver is dependent on the song service but you did not import the song service let's fix it by mocking the service I'm going to copy the same code and paste paste it here we don't have song service let's import it it's not giving me the suggestion I have to import manually I got the song service we also need to get the create song input and update song input I think it will not get this path Source do/ graphql let's add the complete path you can see our test has passed now now we're going to write the test unit test for a song's query it should fetch a song first of all I need to apply a weight expression on get songs it is going to give me this song because we are using our Mo implementation inside the get songs it is going to return this object or this array with a promise here we are just resolving it unable to fetch songs I got the error let me check my song resolver what is inside the song resolver I think I'm throwing the error that's why I got this error let's comment this code and I would like to return this song service with get songs array it is going to give me the array of the songs we are just using this get song method but we are using this implementation this one it will call the get songs but it is it will use our own implementation this one this is how you can fix the bugs with the help of unit testing our test has passed now we need to test a single song query we have created this song actually we need to yeah we need to test this one we need to create test create new song resolver we're just creating a new song and we are expecting it because create song will give me the ID and whatever we passed here the object it is going to return the same object here the test has passed now we need to test update and delete it is giving me the error update song a unique ID we are not expecting the ID in the update song there is an issue I think it is going to give me the ID let's look at the update song resolver song resolver let's look at the update song update song I think I have to change the order first I need to get the ID I need to place the ID and then I need to get the update song input you have to rearrange the order now it should work let me look at the song service ID it's giving you are not using the update song tto title but let's restart the application the error is gone now everything is fine our update test has passed and our delet delete the song test has also passed it is returning the affected that's why I use the affected here in the next video I'll teach you how to do end to end testing graphql apis this lesson I'm going to teach you how to do end to endend testing with graphql apis in the previous lecture we tested unit tested we tested the individual function of resolver now we're going to do integration or end to endend testing we're going to test exactly the API by sending the HTTP request or queries from the HTTP module this is how you will test the songs query and it is going to give me the result I'm using the request request package to send the HTTP request if you are working with graphql there is only single endpoint which is/ graphql it will be same for each query and mutation now I'm trying to fetch all the songs and I got all the songs this is how you will test the end to end testing I already taught you how to set up the end to end testing file when we were building when we were testing the rest API in the previous previous module so before each we're going to create testing module this is a same before all we're going to create new database I have the test database it will drop after completed all the test and after each we're going to delete everything after each test we're going to delete everything from the songs table that's why I'm using the songs Repository do clear method and after all we're going to stop the application we're going to use this method to test it's a helper function to perform our testing nothing more it's just creating a new song and this is how you can test a root end point it means our testing is working fine let's implement it there is no script for end to end testing for the we have an end to end test but I'm looking for a watch mode testing that's why I'm going to add a new script it will run end to endend testing in the watch mode let me run the end to end test in the watch mode it should be e to e e to e right now we have only a single file which is AB do E2 e-pack dojon if you run this file let's say app it is going to run this file I'm going to copy this source code and let's create a new file inside the test folder we will use this test folder for in to end testing let's define a new file song SL do E2 e-. I have copied the source code this is the default code we need to add a type orm setting before all the test we need to create a new database let's run it here we need to import couple of modules we need a song module and song entity let's get it type Ork module we also need to import type or module actually I'm going to copy everything and paste it here now we have before all we also need let's define it should be song resolver end to end test we need after all and after each after each test you need to clear the songs table and after all the test you have to close the application I'm also going to use this helper function I already taught you these Basics when we were building when we were testing the rest apis that's it our setup is complete now let's run the test this time I would like to run songs file let's try to run the song file song. E2 e-pack our test has passed now and you can see this test is running fine now now so we have successfully done the setup now it's time to test the query we need to create the song first because there is no record in our database table which is songs there is an empty here there is no record so I'm just trying to write the query to fetch all the songs I created the query data object I'm providing the query and I'm sending the query in the HTTP request when you test the API graphql API you will get the data or the response in data object and we have the songs I'm just expecting the songs array uh uh let me run the application in development so you will understand it more deeply application is running now let's try to write the query to fetch all the songs if you write the query or you can do without without query I'm going to write query query and I would like to fetch all the songs ID and the title so you got the result in the data object and we have the songs array one more thing if you write the name of the query you can also do that if you have experience in graphql then you will know what I am doing you I'm just I just gave the name of the query get songs you can also do that it will work fine there is no issue now we're going to test a single song query this time first step I created this song and I created the query object now we need the variable this is how you can Define the variable in graphql so I'm providing the variable ID here you can exactly query in your graphql playground let's say it this is a new tab I can give you the name of the query get song let me copy that get song now I def I created the get song query and I'm expecting the ID as a variable here I'm providing the variable ID this is how you will set the query variable this is a another way to fetch the get song query I already taught you this method it will work fine you got to provide the ID and here you can expect the name it will work fine but this is another alternative way of doing this thing if you have an ID you can provide the ID here ID we don't have any record that's why I got the error now we going to test it you can see our test has passed now because first we are creating the song then I'm providing the ID variable from the new song object you don't need to change anything here you can also do expectation for assertion check for the status code here instead of calling this one that's why I I'm expecting the 200 status code and it is going to give give me the response data and the song and I'm checking on the based on new song both are same now our next step is to test the create song mutation it is the same way you define the mutation I give the name create song mutation instead of ID I'm expecting the create song input we have created the variable and I'm getting the create song input we have title and here you can provide the values for your variables if you want you can do the exact same thing from your graphql playground let's say I can say I'm going to create a new song I just past it pasted the mutation if you run there is no query variable for create song input let's define it you have to provide the title I can say lover song you can see the lover song now I can provide the ID here let's test it here I provided the ID so I got the song object there is a data object and we have a create song object that's why I used create song Here create sing do title should be animals our test has passed now we need to run update mutation similarly just like for just like with create mutation it is expecting to arguments ID and the update song input and we are providing the ID in the variables and update song input here here it is going to return the affected with integer now we're going to copy this delete mutation delete is expecting only the ID and it is going to return the affected I defined the delete song mutation and here I'm expecting the value which is one our test have has P tests have passed query and we also need to test delete mutation delete mutation test has passed F this is how you will do end to end testing in graphql in this lesson I'm going to teach you the concept of caching Apollo server provides caching on the server site you can implement it caching is a process of or method of storing copies of file or data in a temporary storage location or cash to be accessed quickly like you want to store the data temporarily in some type of in memory built-in memory you can store the data Maybe for 30 seconds or 60 seconds or a 1 minute it's called caching what is server side caching you want to store let's say you want to fetching the query results you have a query and user is fetching the query constantly after every 10 seconds after every 20 seconds or after every 10 seconds in that case you need caching you don't want to send the request backend server to DB server again and again so it will increase the massive traffic load you are thinking why do why need why do we need caching if user is fetching the query after 3 seconds again and again you did not implement the caching your application will send the request to the backend server DB server and it will and it will fetch the data from that server again and again it will decrease the performance so the help of caching you can improve the performance of your application you can avoid unnecessary request to server because the data will be fetched from the cache immediately you can reduce the bandwidth which will be benefit to user you can reduce the massive DB loads with the help of caching you can handle massive Network traffic request yeah you can decrease the service calls so that was the basic fundamental concept of caching now we're going to implement the caching in in nests project nests already using Apollo service AP poo server Apollo package so we're going to install the package uh install this caching module Apollo server plug-in response cache this plug-in helps optimize the performance of graphql queries by caching the responses this this plugin will help us to Cache the response and serving the data from the cache instead of executing the same query repeatedly our next step will be register the caching plugins when you install this plugin you can register it as a plugins array I have set the default maximum age which is 5 Seconds I'm saying hey Apollo you can keep the data in cash for 5 seconds after 5 Seconds you have to refresh the cache you have to refresh the data and then you need to create a directive cash controls SC private or public you want to fetch the data publicly or you want to fetch save the data privately private represents a cash control scope where the response should be cached privately if you want to fetch the authenticated user something like that then then you need to set the private represent a cache control scope where the response can be cached publicly this directive will have max age scope and inherit max age and you can apply cache control directive on field definition you can apply on a fing field like title field in a song type you can apply on object interface and Union the max age is an optional argument of type in that represents the maximum age of the cach control in seconds how long the response can be considered a fresh and cachable you can read this documentation of maxh I've written down for you private and public scope this will be used for parent let's suppose your query is dependent on parent query then you need to use this one you can also set the cach control set cach hint in the resolver by using this line our next step will be apply the cache control directive I applying it for titled field inside the song type cache control maximum age for 30 seconds I'm saying to Apollo hey Apollo you can keep the title field record for 30 seconds in a cache if user is fetching this title field constantly after 20 seconds or after 10 seconds then it will fetch from the cash if user needs to fetch record after a minute or after a 2 minute it will fetch the data from the DB server but it depends on you on your case on your use case but 30 60 and 40 are the recommended values on the based on Apollo documentation Apollo server uses inmemory cache by default we are we are going to use inmemory cache but you can also configure different backend like redis or M cach you can also apply cash control directive on a complete type let's say if you have a scenario where you need to fetch all of the fields from a specific type then you can add here cache control directive maximum age to 40 seconds I just give you the basics Basics when you implement in real world scenario in real world large application you will know your use case better now it's time to implement it or you can implement it by your own let's install the plug-in first plug-in have installed let's import it in the app module now we're going to register the plug-in into plug array when you are creating graphql module you can register it here so our third step is to creating a cache control directive I can do it here it will have max age scope inherit inherit max age private if you want to dig into more deeper you can look at from the Apollo server documentation when you Google Apollo server caching this is the document you got to read if you want to dig into deeper what is Max age what is cach control scope you can read this document this is the implementation of caching in AP poo server if you want to do ready setup you can also do that we have created the cache control directive now I want to apply the cache control directive on our field right now I have only one single Field title I'm saying I'm assuming that my title field is going to be feted after 10 seconds I have a query in that use case like client is asking title field again and again let's try to test it first my application server has started now I can say I want to access the query of the songs I want to fetch the title you can see it's working fine now let's fetch the title again now it is accessing the title field from the inmemory cache one last thing you can also apply cache control directive on a type here I want to say I have only single type that's why I want to use it for only demo purpose in real world application you will have a different use case restart the application my application is running now I'm going to access this song FEI songs it's still working fine if I try to access the song we need to provide the ID let's fetch the ID I'm going to copy the ID and let me paste it here now I would like to access the ID and the title let's access the title only or the ID now the data is is going to be cached I can access it easily it's working fine in this lesson I'm going to teach you the concept of data loader why do we need data loer we have this schema I've already found example project regarding data loader we have a user and we have a post there is a relationship between user and the post when you send the graphql request to fetch all the post and you also want to the owner of this post who has created this post under the hood graphql your application will send a a different different a new data request to the database a new request to the database to fetch a user for each post this will decrease the performance of your application because you're going to do lot of database request here your output will look like that if I will show you here let me show you with the help of example I'm going to send the request it is going to take a 3 seconds because I have set this delay for the 3 second we have how many post we have we have three post you can look at the schema or our database I don't I'm not using any database here so here is the data we have a three post inside the post we have a user ID when you look at the user service we have all of these users every time let's say I log the message fetching data from DB let's example you can say that getting user ID 1 fetching the user ID one this is the you can imagine this is the database request every time it is going to fetch the post for each user against post it has to fetch the record from the database you can imagine if you want to load 50 post and you have to send the API or backend DB request for each user separately so what data loader will do data loader will batch all of the users it's going to wait and say I can send you request here what data loader will do it will say I will get all of the IDS of the users like one 2 3 and then I will fetch all of the users for all post and then if you need any post if you need any user against each post you will fetch from the cash or from the data loader cash data loader maintains cash also did you get the point let's say I'm going to add I have four users inside the post service I'm going to add post for title post for something and user ID which is for this one application is running now I'm going to send the request to fetch all the post now I got the for post and it has sent the DB request to fetch a single user what we can do we can say I want to fetch if we are using data loader please fetch all the users it's batching all the users from the DB and maintains a cache and next time our application will fetch the user from this cache I have already implemented the data loader in this project actually I found the source code on the internet to explain the data loader it's a simple source code so I thought I should teach it with the help of this source code inside the post resolver here they are resolving the created by field created by and it is going to return the user here instead of loading the user from the database let's user service will send the DB request so I'm going to comment and now you will see the magic instead of loading the user from the DB I would like to fetch the user from data loader now we're going to send the request you can see that getting the users with ID 1 2 and 4 it has bashed all the users and created the user map to send the ID's record to data loader and here is the result so let me explain what this source code is doing if you check the app module here we are providing the loader I created the create user loader and they are injecting the user service inside the user service inside the create user loader I'm passing the user service to work with data loader you only need a single package which is data loader this one you have to install only the data loader here you will have a user loader what this loader will do it is it's nothing more it's just a function takes a user service so I created the instance of a data loader the ID will ID would be number and another type which is the object should be the user this when you create the data loader you have to provide it is going to give me the IDS all of the IDS and here I can fetch all of the users against IDs here I did the users map you you saw the users map here 1 2 3 because data loader Works in this way you have to provide the results in this way like I got 1 2 4 then I did the map to fetch all the records ID 1 2 and 4 we created the user loader I have attached inside the context object remember graph resolver can have four arguments in for context and parent we have user loader here to fetch all the users against a post here this one inside the post resolver I'm resolving the created by field I got the user loader from the context here you need to load the user from the user loader I got the parent I parent record from the post which is the post so I got the user ID which we saved here we have one more thing we have used a schema based approach to build graphql apis but I also wanted to show you another way to build graphql API which is code first approach this code first approach will generate the schema. graphql file automatically it depends on you but I like the most schema based approach but you can use both of them it depends on your use case this is how you will Define the graph qu object type but we have worked with this schema based approach let's say you want to create this graphel type which is posted with the help of code based approach you will say this is the graph object type you can get it from nestjs graphql package and this is the field you can say this one this is the field and you can say title field and we have the body field and we have the user ID I'm not I'm not saving into the graphql datab graphql graphql type that's why I keep the user ID for entity based to build a relationship with them so created by this is the relationship between a user here you can see that created by the return type should not be null that's why I they have used the user this is this represents the return type what your field will return so it's the type of this created by it should return a user user type similarly you can look at the user entity object type this is how you will Define here this is graphql type and my user id the type should be number that should be int that's why it's a nonn knowable field and it should return or the type of this ID should be int and we have a field which is graphical type so this code will be converted into this schema type and how can you resolve the resolver when you look at the post resolver this is the resolver and I say this is the post resolver that's why I provided the post entity now we have the post resolver the query tag so here you want to say what resolver this will do in we are in the post we are here so this query will return all the post and the name of the query should be post I'm resolving this query so I'm fetching the post similarly if you want to resolve the created by here this one you have to provide the resolve field is all field there is a field inside the post Ty which is created by and it should return a user so this is the return type this is how you will mention the return type it should give the user and I got the parent and the context this is a uh nextjs has documentation on graphql you can learn more about a code based approach if you like the code based approach you can learn more about from the documentation this is the code first approach the object types you can read the documentation if you are not getting what I'm talking about you can just read this text it will help you to understand the code very easily so this is how a field and type should be post array I want you to check this documentation one more package I want to share you have graph nestjs graphql tools if you want to use the code based approach and let's say you are using post or type orm this is the package if you want to work with database and and you want to use loader they have already built a data loader here if you like this package you can implement it it's simple you need to provide resolver user object type user resolver here it will have graphql loader you only need to just provide The Decorator graphql loader and it is going to implement the loading stuff here if you like it you can implement it there is a this is how you will Implement one to many many to one and this is the usage I just want to show you you can do if you want to use database and data loader you can Implement by using this package this package also have more features on pagination sorting and field extraction Etc if you want to fetch data from external rest API you can do that we're using Apollo server AP poo server provides a package to fetch data from external rest API a poloo data source rest I have attached a started project I have already in I have already have this package in package.json file you have to install it Apollo data source rest you have to do npm install to install all the dependencies this is a class you have to extend it we're going to do we're going to fetch todos from this Json placeholder API it's a fake API with real data let's say I want to send to-dos request it is going to give me all of the to-dos I want to fetch this rest API now this is how you will implement it you will have this schema you will create the schema to do ID user ID title completed with Boolean I'm using the same property I defined a graphql type and then we have a query query to fetch all the to-dos I have a to-do module inside to-do service to-do resolver now to-do service is is going to f fetch the data from external rest API instead of data database inside the to- do service here you have to extend the rest data source it will it will ask the call the super Constructor this is the base URL I'm going to call this.get to fetch all the to-dos you can use this method I I can get the data source object from the context here you got call data sources. too api. getet too I'm talking about this too API like this one so another important thing this is how you will add a data sources inside the context it's an asynchronous so I provided the data sources if you want to implement you can go ahead and do it and let me do that for you I have I have to do docraft in my started kit project now let's extend data source rest rest data source let's have the Constructor I'm going to call the super Constructor now let's set the base URL I can get the base URL from here I don't need to provide todos this should be the base URL now let's define a function to get to-dos and it is going to return the array of to-dos I can get the type from the source. graphql file the typescript file I've generated the typing by executing this command npm run generat typing so let's call this dot here disor get and provide the path to do is everything right I can check the path which is to do so we created the data source and now we have to add this data source into to do resolver we got to call this actually we need to add in the context I'm going to create the data sources function it's going to return a to-do API let's create import to-do service it's going to return the object and the function is going to return the object now I can add in the context here it looks good so you can use the context object here inside the to-do resolver to do resolver let me get the context data sources and I'm going to call all this method data source is a function there is a to-do API object and we have get too function let's start the project project is already Runing on 3,000 let me stop the project let's run it again my project is running I'm going to send the request I got all the 200 toos Unfortunately they don't have pagination otherwise I can implement the pagination but you got the concept how to implement the rest data source if you want to do more Advanced Thing by using the rest data source package there is also a caching functionality you can override the method I want you to check the documentation if you want to implement the rest data source there is also a data loader you can also use the data loader with rest data source I want you to check this documentation it also provide to fetch duplicate records you can read the documentation to understand how to use the cache stuff like that in this module we're going to use Prisma orm and we're going to build rest apis Prisma is an orm in nodejs or JavaScript when you look at the documentation it's they are saying it's a Next Generation orm for nodejs and typescript project it's similar to type orm but it is faster it's an efficient they are maintaining this project regularly so you can look at the use cases and customer stories when when do you need Prisma you can read the customer stories and use cases so in this video I'm going to teach you how to set a Prisma in next nestjs project you can also get the Prisma documentation from nestjs package from nestjs package inside the njs documentation you will find a Prisma folder you will see the Prisma section here is a Prisma orm documentation the first step we need to install the Prisma I have provided the started kit code for you you can go to the starter branch and run nbm install to install all the dependencies this is just a basic Nest CH project I don't have anything here just Basics basic setting for nest CH project it is taking some time to install the dependencies meanwhile I'm going to create a new database for Prisma because we're going to use postp with Prisma I'm going to create a new database Prisma API something like that you can choose any name all the packages have installed now we need to install a Prisma as a dep dependency Prisma left dependency has installed now we need to initialize the Prisma project I can use npx init Prisma in it it will set up the Prisma in our project you will see schema. Prisma file inside the Prisma folder here I'm telling I'm going to use Prisma client Library this is my post database provider this is my database URL they have also added a created EnV file here we have postp database URL make sure you have ADD theb in the git ignore I think I've already added it yes no I cannot see that let's add EnV I don't want to put push my EnV to GitHub they have already installed post so I'm going to work with post this is how you will set a Prisma in your project in your nestjs project in the previous video we have set up our Prisma application now we're going to create our first model I'm going to create the song model the type should be int and by default this should be int by default I'm going to set it to Auto increment and this is the ID let's add another property this time the type should be string but we did not set database URL for the post I'm going to create a new database let's create a new DB Nest Prisma app or Nest prisma-p my username or owner is postgress now we need to replace the owner here postgress and your password and the name of your database and schema should be public I'm going to run the application my application is running fine let's try to check the tables inside the schema I'm going to refresh and inside the tables I cannot see any table because we did not migrate the database let's create our first migration migrate F Prisma migr F and the name of your migration I can say in it this is my first migration I think I did not provide the right command Prisma migr DB or Dev yeah npx PR migrate Dev Das Das name of your migration this is my first migration that's why I chose the init name but you can choose anything here Local Host provided DB credentials are not valid post SC there was an issue with double s now a new migrations folder has created inside the folder we have in it migration file we have song table this is the migration log let's try to check in our database I'm going to refresh my tables and you can see the song table in our database but we also have two columns ID and title in the previous video we have created our first model and we ran migrations but Prisma also provides a Prisma client to perform cred operation this Prisma client will generate the correct apis correct functions for song model you will have prism client. creat song prism client. find song all of these methods in the prisman client Library here we are using the prisman client but we have to install this package Prisma client and P install at Prisma client this package will provide scrud operations for all of your models this Prisma client will interact directly to the database so we created the Prisma Cent installed the Prisma client now we need a service inside the source directory and I call it Prisma dos service. s it's injectable service exort class Prisma service and I'm going to extend the Prisma client Prisma client here we also need to implement on module in it because we have to set up the Prisma client when our application is running I can call it on module in it on module in it this do connect this connect method will connect our uh connect this Prisma client to our database I have I have not imported injectable decorator let me get it that's all you need to connect Prisma client to our database so we will not use Prisma client we will use Prisma service to interact with database we're going to talk about how to create cred operations we have created a song model here I want to create the correct end points one more thing I did not talk about or I did not teach there is a resource generator this CLI command will generate the correct API endpoints controller module service dto object something like that if you need to scaold your application you can use this command resource it can also works with work with graphql code first approach schema first approach or you can create a micro service or you can create the web socket but I chose the rest API because I would like to build the rest API yes I also want to generate correct entry end points we have the songs model we have d object entities so on controller service we have all of these method inside the service we have created a Prisma service now I'm going to use a Prisma service here to interact with database can call it Prisma Prisma service it is going to give me the error that's why I use this path first of all let's create the create method return this do Prisma Dot Song you can see we have a song object there is a create method and you have to provide the data here you have to provide create song dto one more thing I want to talk about you can use the types from Prisma client Prisma client already generated couple of typescript typing let's say first I need to import Prisma from Prisma client you will find book create input the type in this type you will have title field we also need to update inside the song controller we got to get Prisma client and you will have book DOT book create input my vs code is not giving me the hint or suggestion now we're going to run the application it is going to give me a couple of Errors maybe oh it's not a book it should be a song because I'm accessing the song model I'm using the book song song. input not a book song create input I did not import Prisma service inside the song module because we have to import it that's why you have to register it as a provider Prisma service so I can get the Prisma service my application is running fine now now we're going to test it with the help of fresh client let's create a new file I can say HTTP client. HTTP create song post HTTP HTTP Local Host colum 3000 SL songs what is the name of the API I can check it from the controller we have the songs content type application Json let's provide the title follow me you can see a new song has created successfully now we're going to write the function to fetch all the song This start Prisma I'm going to reload my window it is not giving me suggestions Prisma Dot Song dot find many there is a method find many let's try to get all the songs you can see I have a single song now we have to implement the find by ID this do Prisma do song now it is giving me suggestion find unique and we have to provide the ID where clause and you have to provide the ID let's try to fetch the song on the based on ID fetch song by ID so I got the song by ID if I provide the invalid ID I should get the empty record I'm getting issues here I think I need to generate the typing you can call this method npx Prisma generate it is going to generate the typing inside the node node modules and Prisma inside the Prisma you will get the typing I got this from documentation this typing will be stored inside the node modules inside the Prisma and the client directory generated Prisma client reload the window now the error should be gone now I have to update it it's a song create input we also need to update in the controller we have the song controller here it should be Prisma Prisma SL song create input I have to get this ke Prisma client now the error should be gone now it looks good so I can create a new song and I can fetch all the songs that looks good in this lesson I'm going to teach you how to create update endpoint actually we have already created the update endpoint you will see the patch endpoint Point inside the song controller there is also a method inside the song service there's an update method all I need to do is to use a Prisma service inside the song service we have have to use the update method from the Prisma and there is an update method inside the song update here you got to provide we clause and the data where and data we have to fix a little bit changing here I'm getting I'm going to get we clause and I can get the type for for Vi song We unique input similarly I would like to change the type here Prisma do song update input you can remove the V because both the key and the value are same so I can use a single V we also need to update the type in controller file let me update the type here here I would like to send the object instead of single parameter which is ID here I can change the type Prisma do song update input we also need to update the find one a little bit I would like to get the songw unique input and let me get the songw unique input and I'm going to provide song wear unique input we also need to update controller for the find one let me send the ID in the object because I'm receiving the object here here if you want to look at all of these types where these types have stored when you go to the node modules you will find there is a package Prisma do Prisma client you will have all of your types in index. D.S file so I can get song whereare input you can see we have a song We input can say type here here we have a song We input you can have ID and the title here we have the song where unique input you have you can have ID and or note in the title now we have to test it run run the application cannot find primsa let me fix that there is an issue Prisma now my code looks good I'm going to send the update request from my rest client from my HTTP client the song by ID we have to send the patch request instead of put and going to update this song with id2 copy the content type dancing feet let's see a song has updated successfully if I fetch the song on the based on ID it looks good we have dancing feed let's create another song I have created another song I would like to update the title my title has updated so you can fetch all of the songs it looks good we have implemented the update operation now now we have to implement delete operation I'm going to use the same strategy to delete let me get the ver clause in the input there is a method in the Prisma Prisma do song. delete it is going to accept the V Clause now I have to get it in the controller we need to pass that inside the song controller here I have to provide the ID inside the object ID let's try to test it with the help of HTTP client I can say delete song by ID I'm going to provide the ID instead of patch we need to use the delete operation you can see this song has deleted I can verify by fetching all of the songs you can see we have only only two songs right now now we're going to build relationship between models Prisma also provides one to one relation one to many relation and many to one relation and also have many to many relation I'm going to add a new model artist let's add Fields inside the artist I will have the ID and the name of the artist now each song an artist I'm going to add one to M relationship between artist and songs each artist can publish many songs I saved the application you can see it has automatically added a relation let's rename a small a to a capital A to small a here you can see there is a reference here artist and fields which is artist ID and the reference with the ID now we have to run the migrations npm run migrations oh I have to run npx Prisma migrate Dev the name of the migration which is ADD artist it has also generated the Prisma client queries or Prisma client types when you see the migrations you will have the create table cury it is going to create the artist table it has also added a relationship between song relationship between songs model let me try to check the types you can check it from Prisma client index. D dots do I have the artist type yes let me find artist create input yep it has generated the types for me now I'm going to generate a new resource for artist an artist resource has created I don't need entities I'm going to delete them here I also don't need entities in this song because we are defining our models in the schema. Prisma file let's create the artist we have to open the r service and here we need to inject the artist the Prisma service I can get it from the song service which we have to import these two dependency Prisma service and the Prisma client I'm going to copy the Constructor here we have to find the Prisma create input command F to to find artist create input yes I would like to use that type I can get it from the Prisma client Artist Artist create input that's it now I can use Prisma do artist do create here we have to provide the data object and inside the data I can provide create artist dto one more thing you need to add Prisma service in the artist module we have to register it Prisma service let me import Prisma service and here I need to add Prisma service we also need to adjust a type in the controller for artist controller we have to update our type I have to use the same type Prisma dot artist create we have to import a Prisma otherwise it will give you the error I'm not going to use the create artist dto so the artist create input can take the name of the artist if you want to inject the multiple songs you can also do that you can look up the documentation of Prisma how can you insert multiple records if you want to do in this way you can also do that artist unchecked create input but I'm going to use this one simple one npm R start Dev my application is running fine now let me open the HTT HTTP client let's send the request to create new artist create Artist Artist here I can provide the name of the artist can say Martin Garrick a new record has created successfully the artist record has saved let's add a new artist V another artist has created we have made one too many relationship between artist and songs when you add a new song you can add a relationship for the artist here when you check the schema. Prisma file you will have the artist ID in the song model that's why we need this is how you can build a relationship between song and the artist so what I can do inside the song service we have to expect the song actually author ID I can find that song create input so I have this song create input type I also have song unchecked create input did you notice the difference between these two types here we have the artist ID I can add the artist ID if you want to insert a complete artist while creating a new song you can also do that you can look up the documentation and here you can you can do in this way you can provide the array if you want to do that if you want to insert a single record you can also do that but I just want to show you the way to add record so I'm going to use this type instead of simple song create input now you also need to provide the author ID in the in the request parameter here I'm creating a new song here let's provide the author ID which is one I'm going to create a new song let's say Animals by Martin gck I got an issue not an author ID it's an artist ID why I'm saying the author ID I got the record with this author ID if you want to query the artist in the response let's say I'm going to I'm going to fetch all these songs but here we have artist ID null here we have the artist ID one if you want to populate the record of the artist you you can do that in the find menu and here you can say include artist to true that's it let's fetch all the songs here the artist ID is null artist is null here you can see the artist ID one and we have a complete artist record that's how you do population we have used this include syntax you can also use the connect object if you want to make the connection or update the reference ID you can use the connect now we're going to implement one to one relationship between two models we're going to have a user model here we have a one to one relationship between user and profile each user will have one unique profile in the profile we have photo we have the phone number of the client of the user this is how you will make a one toone relationship user and a relation and this makes each profile will have a unique ID of a user table then we will generate Prisma migrations then we will generate a new user with the help of nest generat resource a user we're going to use cred AP endpoints and finally we're going to save a user on the based on profile like when we are when we are saving a user I also want to save the profile this is how you can do that profile and a create object and the attributes of profile table it will automatically made a relationship between user and a profile and finally I want to fetch all the user with the profile if you want to implement it you can do it but let me show you how can I implement it I'm going to copy the model here here here inside the schema let's add two new models I've added two new models let's run the migration npx Prisma migrate Dev the name of the migration one to1 relation it has run the migrations and now it has also generated the types inside the Prisma client I can double check that from the Prisma here you have all of your user types user and profile when you search the profile here we have profile stuff our next step is to generate a resource Nest generate resource users select rest API end points getri of the entities and I need to inject Prisma service inside the module inside the users module I have to inject the Prisma service here Prisma service inside the user service we need to inject Prisma service dependency I can get that from the song service we need the Prisma service and I'm going to copy this one as a Constructor so we have to call the create method I'm going to copy the exact create method and provide it here that's it this time I'm going to use the create user dto I have not defined the properties in the create user user dto if you want to add the validation you can use the class validator I taught you earlier in the previous modules we will have photo the URL of the photo should be string and phone number the type should be string now we're going to I'm going to copy find all method and I'm going to use this profile I want to fetch the profile with each user now let's try to test it run the application this create object is used to create an nested object a relation relation object let's create a new user users provide the name of the user jendo and we have to provide the photo URL some api. com/ phos 1. J APG and you need to provide the phone number let me create a new user a user has created successfully let's try to find all the users VCH users here you can see that I can see the user and we have the profile object inside the user you will also see a relationship with user ID one which is one that's how you implement one to one relation in this lesson you're going to learn how to implement many to many relationship between models I have this use case one blog post can belong to many categories and many categories can belong to a single block post so there is a many to many relationship when you implement many to many relationship you need a third model in the third model you store the foreign key of your first model and the foreign key or prime for foreign key as the primary key the foreign constraint here it's a it's a foreign key of category table and in Prisma you define the primary key by combination of post ID and the category ID this is how you will make uh many to many relationship now the categories instead of categories array you will use the categories on post array the same stuff here instead of using post array here you will use the categories on post array and then you we will generate migrations we will generate migrations and it will also generate the Prisma client types and then we will generate the resource post we will create the post by using this input type post create input and I also have to update the type in the controller and this is how you will send the request to create a new post here the title of the post one to many relation this this is the Prisma post and it it can have two categories here you can say I I'm going to create a new category this post can also belong to Prisma category this post can also belong to nestjs category that is why I created two categories you can see that category number one and this is category number two here I here we have the array of the categories similarly you can do the same thing if you don't want to create a new post you can connect with existing post I'm going to teach you transaction let's say I'm going to write blog post on transactions in Prisma and here this post also belong to nestjs category and Prisma category that's why I'm I'm connecting to category number one and the category number two and finally you can also do a relation queries with the help of this type post where uni input also have to update in the controller this is how you can send the request categories this is a we Clause category and the name you can check all of different type of queries in the documentation let's try to implement it first if you want you can Implement by yourself many to many relation I'm going to create a post model and my next model model is category it will have name and the ID and my third model is categories on post I'm going to save now you can see that these two properties are inside the categories on post I would like to store the date and I want to store who has created this let's run the migration it has also generated a Prisma client types you can check it in the node modules at Prisma / client our next step step is to generate the post resource we're going to perform some cred operations please select the rest API yes I want create entry end points I have the post get rid of the entities one more thing I would like to register a Prisma service inside the post module otherwise you will get the error now we're going to write the code in to create a new post we also need to inject Prisma Service as a dependency I'm going to copy these two lines and I'm going to paste here Post Service let me copy The Constructor we need to inject the dependency I'm going to copy my create function something is missing I have done something wrong so let's you use the Constructor pris private Prisma and Prisma service let's use this type actually I don't need that let me copy the fold create what is this now it looks good so we also need to use that post create post create input in the post controller let me import Prisma now it's time to test this application the application is running fine let's send the API request I'm going to copy my API request here I'm going to create a new post and I'm going to also create a two categories so you can use the create array inside the create array I have the category this is the post on category object so that's why I use that properties let's send the request it should be 3,000 or 3,000 it should 3,000 now you can see that one to many relation post has created successfully now it's time to do a register another post this time I don't want to create a new category create a post with existing categories I would like to create a new post and I want to use the category number one and category number two let's create a new post has created it has also made a connection with this category you can double check from the PG admin meanwhile I'm going to write the code to do relational queries let's update the find find all that looks good we also have to update the get inside the post controller now we have to fetch all the post with nestjs category so you can do that you can learn more about how to do queries in Prisma documentation I'm going to send the request the post the should be 3,000 now you can see I got these two post with the help with the I justed query with category what is my name of the database let me get it from EnV PR Nest Prisma DB here I have Nest Prisma DB let me find the tables and we have post category and categories on post let's look at the post we should have two post you can see I have one too many and transaction I must have two categories you can see that let me find categories on post here you can see I have four records there is another way to use transac ction feature if you have to perform the batch or bulk operations like delete manyu create manyu and update manyu you can use all of these in a one query you want to create three records you want to delete two records or maybe you want to update a single record or maybe you want to update five records so in that case let's say if any query fail then all of the operation will be discarded I'm going to run multiple queries at same time if any query failed you will not get result back you can use this query or transaction API when you want to create batch operation here is an example I want to find all of the post I want to find all of the artist I want to find all songs I want to find all applications in a single query if this query fails it is going to give me the this operation this complete operation will be discarded I will not get any result that is why you use this transaction API to implement the demo or to implement the transaction API let's do it in app controller we have to inject Prisma service I just want to show you the demo how can you use the transaction API this my service we have to inject it here I can say transaction let me register Prisma service now I have injected it here we have to import it sounds good I'm going to create a new method with name sequential and get sequential result results this could be the name of the query and here I'm going to copy my code so let's try to test it I'm going to run the application let me send the request for sequential query in my HTTP client sequential query HTTP Local Host colum 3000 and sequential you can see I got the result of all of my post applications this these should be post the songs and here you will have application these are all the applications with customer ID this is how it will work if you want to add include or to fetch nested record you can also do that now I'm going to talk about the concept of nested queries this topic already is in the transaction API I'm talking about transaction when you have this type of use case let's say first I have to create the customer email customer or the user and then there is an address let me look at the model structure we have a customer model and we have an address model there is a one toone relationship between customer and the address and I have created the enum application type and I have the application model and the type should be application type and default to now and I choose a loan loan here and I have made one to many relationship between application and the customer we have the applications array here so let's say I want to create a new customer address and here I'm creating a new address and here is the Fe here are the fields of customers and I'm going to create applications basically we going to we are talking about a banking type application let's say a customer comes to apply for the loan customer can apply for multiple loan applications loan car financing or business financing a customer can apply apply all of these or can can apply to one or second type application so tenure of your application would be 5 years or 2 years how many amount you want how much how much loan you want so this type of application when banking banking in banking application when an application comes they create a new customer record they create the address and they create the application based on current user or current customer demand let's say a new customer comes with business financing application John wants to get the business financing from a bank so he's decided he's going to apply for business financing application what under the hood is saying what under the hood banking application will create a new customer they will create a new address and they will also create a new application but they have a feature a customer can apply for two loans two applications or three applications he can also apply on business financing he can also apply on car financing so that's why there is a create array here what what are the benefits of using transaction under the hood Prisma is using transaction when you run the nested queries these are all the this is the nested query we are creating address and we are creating applications this is the nested query let's say if an error comes here if I will add the invalid value here it will not create the complete app application it will not create the customer it will not create the address so that is the benefit of transaction I'll show you with the help of demo this is how you can implement the nested queries in Prisma I've already done that for you I'm not going to implement it here first of I can walk walk through the code I created the customer model we have the ID we have the name field we have the email we have the address and we have the applications array so address should be here it should be at the top here so I have made a on to one relationship between address and the customer here is a unique denotes to denotes to one to one relationship we have Zip City Country inside the address and there is a on toone relationship between customer and the address but I also have one too many relationship between application and customer so I told you a John can apply for car car financing he can apply for business financing that's why I use the application array so the tenure amount application type I have set the default to loan so that was our model structure next step I have executed nested query Migration by executing this command nested queries here it is going to create the customer table it is going to create the address table and create the constraint with customer and the address it is also going to create uh application table and create constraint between application and the customer and then I have set the default value to laan and then I have created the application resource by running Nest generate resource and you will see the application inside the application module I have injected the Prisma service and then here I'm injecting the Prisma Service as a dependency and I just called create application dto by using the customer customer create input you can double check it from the customer create input you can get name email address and application all of this stuff here name email address I provided the address and I'm creating it here I also can provide the applications array you can check the type by copying it and type and paste so it should give me the this one type so I got this application create nested with custom customer input so I use the create did you see I use the create can have the array so create can have the array here so you can provide the application object here if any fails the transaction will roll back or discarded the operation let's try to test it you have to send the AP request inside the HTTP client here I'm going to send the API request John J 2 jendo City New York ZIP code this one amount he wants say 10,000 inue over 5 years and he wants business financing I'm going to create a new application you you can see a new application has created if I provide the invalid value I have set the integer here I'm providing the float or float value I got the issue now it will not create an application you can double check it from PG admin that's the benefit of transaction in this lesson you're going to learn the interactive transactions what do I mean by interactive transaction when one query is dependent on another query one query result is dependent on another query result let's take a use case you're going to build account transfer feature in banking application we're going to build this use case a John has an account in a bank and he want to he want to transfer the $100 to Sam account so what would be the process you have you have to implement as a developer you have to update the J account or deduct the $10000 from a Jone account and then you have to check the balance of JN account if balance is less than zero you have to roll back the transaction the operation should not be continue so this query result is dependent on this query result you can see if any of the step fails operation will be discarded if there is an error occurs here it will roll back the transaction so first of all we need account model we will have these properties ID balance and the title then we're going to generate migration and resource for accounts we will inject Prisma service here I will use Prisma account create input and I'm also going to update in the controller we we're going to create first account John then we will create second account which is Sam and we will implement the logic to transfer amount to One account to another account I'm going to create a route Handler for transfer we will need transfer account dto because I cannot use from from Prisma types there is no specific type for transfer account I have to use the custom data transfer object here when I will transfer I will send the transfer account request you need to provide sender ID receiver ID and the amount you want a transfer so we will create a simple basic transfer from transer method inside the account service here is the logic from the controller I will get the sender and I have renamed to from here I will have receiver I have renamed to two and I will get the amount and first we will deduct the balance from the John account by getting by getting the account on the Bas ID here decrement the amount from the John account then we try to verify the balance of the John if balance is less than zero we have to send the error back and we have to roll back the transaction here we here we got to roll back the transaction but this transaction object will do for us and this transaction function it will take all it will take it's a it's a call it's a asynchronous operation it it's going to take TX so first this is the asynchronous operation if error comes please scroll back the transaction do not deduct any amount from the John account and here is our second operation if everything is fine we got to add balance to the same account and finally we have to return the balance or return the recipient that's our trans transer process this is how you can test you have to provide the sender ID receiver ID and amount you want to transfer here I'm saying I want to transfer $50 from join account to Sam account and here I want to transfer $40 from J account to Sam account we created both account with $100 now if I try to send $20 now John will have $10 in account in his account if I try to send or deduct the $20 from Jo account you will receive this error balance is less than zero and our transaction will automatically roll back this operation that's how the transaction is helpful when your one query result is dependent on another if you want to implement it you can do it on your own but let me do that for you first of all we got to create a new model inside the schema file I have already done that model oh I have to implement here interactive transaction op schema. Prisma and we have to add a new model finally we got to run the migration migrate not a migrate also have to update here M crate our next step is to generate the accounts select the rest API let me delete entities and we have to register a Prisma service inside the account module I can register as a provider Prisma service and we have to import Prisma service Prisma service from Prisma service let's inject Prisma service inside the account service I'm going to do dependent see injection I have to copy this line and I'm going to paste it here I also need to get Prisma client so I imported the Prisma client let's rename or add a logic to create a new account we got to do the same stuff inside the account controller import Prisma let's run the application and create two accounts in our database for testing e application is running now I'm going to create a new account let me send the request for account creation board should be 3,000 not 3001 so I have created the account John now we have to create another account with Sam name account has created let's implement the transfer account logic transfer amount not an account transfer amount logic open the account controller we have to register a new route for transfer amount I'm going to create a post method we don't have transfer dto let's create that transfer dto in our dto accounts dto transfer account - D.S so here we have transfer account dto we also don't have a method yet inside the service account service so I can open account controller let me import transfer dto we don't have method I can use the vs code please declare the method inside the account service now you will have a method inside the account service this is the transfer method so here we're going to implement our logic to transfer the account from John to Sam I'm going to copy the complete op complete function I'm going to paste it here so everything is good to go now we have to test the process let's send the transfer amount request it should be 3,000 let's deduct the $50 from John account to Sam account I'm going to deduct $50 from John now you can see the balance of the Sam if I deduct the $40 again let's use it here so now the Sam has 190 and the John has $10 if I try to uh deduct $20 from John right now the balance of John is 10 it should give me the error you can see I got the error one does not have one the ID sender sender ID with one does not have enough to send $20 so I got the eror so I got the error here my transaction function automatically roll back back this operation that's why transaction is very helpful if you are doing 1020 operations or 1020 queries your one query result is dependent on another another query result is dependent on another let's imagine after 10th query there is an error then the transaction will do the roll back for you in this lesson I'm going to teach you how to upload the file in njs nestjs has already created a molter module if you have used molter in Express we're going to use the same logic they have created the molter module they also have nests platform Express to implement file upload feature so this package provides the typescript typing to work with multer package which is a middleware for handling multiart form data and then we will create our route Handler for update they have we're going to use the Interceptor that's why I use the use use Interceptor decator here we have file Interceptor they have already created this file Interceptor and you got to provide the name of your file and here we will have the upload file decorator the type should be express. multer do file that's it then it will log the file when you send the API request from Front End application or Postman to upload a file it will receive the file so this decorator indicates that the method should use the f file Interceptor Interceptor to handle the file uploads the string file inside the file Interceptor decorator refers to the field name in the request body now we're going to implement this file upload method first of all we have to install the molter type I've already attached the started kit project or if you don't have an sjs project you can create a brand new project and start from them start from there we have installed uh package now I'm going to copy the same code and I'm going to do it here inside the app controller we also need to import file Interceptor from nestjs platform Express whenever you need to upload the file you have to use the use Interceptor and they have created the file Interceptor the name of the file here you will provide the molter options when you worked with molon if you already work with molter opt molter package these are the options are same these options are same when you work with molter package so I'm not going to do it here and we will have upload file now we need to test it I'm going to start the project we need a postman to send the API request in terms of file so here I'm going to send request to the upload and we have to provide the file select the body and you got to provide file you can select the file from here a body and a file and then you have to select the file I'm going to use this PNG file you can choose any file B request I have to remove this one now I'm going to send request you can see a file has created successfully actually uploaded this is the original name this is the field file but I want to save this file some somewhere in my folder you can create a disc folder and you can save save that save there to implement this logic you going to provide these two options actually I'm going to copy the complete file intercept use intercept I'm going to copy the complete use Interceptor now it looks good so we have to import this package from disk storage I think I can get that from molter package molter disktop storage now it looks good so it will create the upload folder for me and here I will have the files folder now we're going to send the request to save upload the file and you can see there is a file inside the upload folder and inside the files we have create song mutation. PNG file you can also add a validation let's say you can say I only want to accept PNG file how can you add a validation I can say upload PNG you can do the validation upload PNG file you can implement the validation here let me copy the validation logic they provided the pars file pip Builder what this pipe Builder will do this is a custom utility that creates a pipe for validating uploaded files if you want to add a maximum size you can can accept you can also do that but I'm not going to implement that we need this logic inside the upload file here I also added an error status code if error comes it is going to log this error message unprocessable entity now it can accept only the PNG file type I've applied the pipe to add PNG validation let's test it out if I add upload PNG if I add invalid file what will happen I'm going to add jpack I got the error oh upload Das PNG I got the error for double to unprocessable entity if I provide the valid file which is PNG what will happen can get that from here this is the PNG file now the file has uploaded successfully here one more thing we got to return the message I forgot to return the message from here to also need to upload the message file uploaded successfully let's test it out out this is the PNG file you should see the message file uploaded successfully and you you will see your file here in this lesson I'm going to teach you the concept of custom decorator if you want to add additional functionality to a class to a method you can use custom decorator just like we did with app module app controller we use decorator a lot when you look at the app module here we have used a decorator this module decorator in the controller app. controller we have controller decorator it mean this decorator is adding an additional functionality to the app controller like they are adding metadata this controller can have functions attributes all of the stuff so you can improve your modularity and reusability with the help of custom decorator you can organize code very easily you can extend Nest functionality by adding custom decorator here we're going to use custom decorator I have a basic simple example we're going to create our own custom decorator the user decorator. this you use pram decorator so I can apply it on a parameter and I'm using a function this function is accepting to argument data it should be unknown type and we are getting the execution context and I can get the request from this execution context here I'm am adding a user into the request. user when you have implemented auth tication you can create a custom decorator for a user imagine you can get this request. user from a Json web token and Json web token Parts the token and found the user you can imagine that but I hardcoded it and return request. user yeah this is The Decorator Factory function it takes to parameter data and the Conta execution context and now we're going to create a new user entity here we have applied a user decorator let's say this is this is authenticated route only authenticated user can access this route so I would like to get the user so you can use a user decorator and the user entity this user decorator is going to execute this function and this function will be executed and it is going to add a user in the request EST object that's how you can implement the custom decorator let's create a new file here I can say a user decorator decorator. I'm going to copy my code user decorator you can use any name here I also need to create another entity this time I'm going to call user. entity TS now we're going to apply The Decorator on a user do I have a route I can create the complete route to implement this user decorator copy this and and paste it here and we need these two Imports now we have to test our application so whenever you need to get a user inside any function all you need to do is to apply the decorator here you can apply The Decorator upload file you can apply decorator here it depends on your use case so my application is running I'm going to create a new HTTP client. HTTP file to send API request can say that find user only based on ID we have to send the get request 3,000 slash user and you got to provide a user ID now you can see I got a user so this decorator a user decorator is calling the user decorator function and this function is getting a user or setting a user to the request object and returning the request get decorator is nothing it's just like a function here in our case I'm running a function here uh in this lesson I'm going to teach you if you want to schedule any method or any function you can do with grown task uh let's uh if you want to schedule any task let's say you want to run you want to calculate the expiry date of a license let's say your trial version is going to be expired after 7 days You're Building this type of SAS application you your company provides 14 days free trial and the trial version will be expired after 14 days what your application will do under the hood application will run a crown task it will execute every day in try to find out the expiry date for the current user if user has used software for 14 days your Chown to will determine that and it will send the notification to the user into your application hey this user has used 14 days free trial and you may must have a logic or a code to handle this situation maybe you can send the credit card information to upgrade so nestjs provide a package to implement this type of functionality we're going to we're going to we're going to install a couple of packages first you need next JS schedule and you also need or I can install it here types of grown actually I need a type as a Chone SE as a Dev dependency let's first install this package now we install the types or I can use the minus t and types Chone NJ has provide a schedule module from nestjs casual package I have to import it if you want to use this package let's import the module schedule module I have to register it or create this module this root module will initialize this casual module and it will register any declarative chrone jobs timeouts interval that exist assist within your application right now we did not Define any Crone task if you have defined Crone task this for root will initialize all of your crown task and registration occurs when the application when the own application bootstrap life cycle hook occurs now we're going to declare some cras this cronas will run the function autom automatically we will specify some specific dat time when this Crown task will run it depends on your use case do you want to run this Crown task every week or every day or every 5 minutes or every 10 minutes or every hour it depends on your use use case now we're going to create a new task service let's create a new to service so let's define our first gr task in task service private read only logger it will log some message task service do name if you want to Define a crown task you need a decorator in the previous video I taught you what are the benefits of decorator like I can extend the functionality of a function by adding the Chone decorator here you will provide your time path time date something like that so start start start you can learn learn more about this strategy by looking at Crown task schedu Nest or npm you can play around with these timing settings from this package this package you can learn more about how can you set the current dat stuff like that here the first star represent second the second star represent minute the third star represent R and the fourth star represent the day of the month and the fifth star represent the month and the last star represent the week day did you get that let's say I want to run the crown task after every 10 seconds so what I want to do I want to log a simple message after every 10 seconds and say Myron task I'm going to log a message this do logger not a throw this. logger do debug called when the current second is 10 let's try to test the application I have registered the schedule module here this for will will initialize this method and we set up the configuration to run after 10 second let's do that you can see it has run this debug after every 10 seconds what if I change the setting to five now after 5 Seconds it has executed e actually it is running called when the current second is actually it is wait it will wait for 1 minute and 5 Seconds then it will run wait for 1 minute and 5 Seconds is now you can see at 519 and then it has ran after a minute and on the fifth second what if I run this cronas after every second you can see it's running after every seconds so I can use that called when the crun C call that's it so it will wait for a minute and a 15 seconds if you want to do a little bit setting let's say I want to run every hour at the start of five uh at the start of the fifth minutes but it depends on you how you want to run this will run after every minute yep after every minute it's running this is how you can play around with crown task in this lesson you're going to learn cookies cookies are small pieces of data dat a server sends to a user browser while the user is browsing a website these cookies are stored in user device and are used to store information about the user interaction with website if you look up the Google Chrome you will see the developer tools and you can find the application tab here you will find all of your cookies if you have stored we have only single cookie you can Implement also cookie based authentication just like we did in authentication module we saved at Json web token into a local storage but if you were if you work with a local storage or front-end application you can store your Json web token in this storage but you can also use a cookie and you can save your token in encrypted format so these are all the use cases of cookies like most of the time when you when you access or fetch or look at the same look at the website or when you visit the same website again and again the next time it tries to fetch the data from your cookies it has saved all of your authentication Lo all of your password in cookies when you go to the Google password manager where all of this data is stored all of this data is stored in your cook is remember when you look at the history or let me you look at the history if you want to delete all of your data it will also ask you hey do you want to do you want to delete all of your cookie stuff you have data inside the cookie so you can save any token inside the cookie let me talk about the use cases of cookies you can manage user sessions let's say if you want to expire a user session after 30 days or after 24 hours you can have that type of logic in cookie and this cookie will be stored here inside the application and the cookies tab if you have any type of shopping cart application you can also do a little bit saving in the in the cookies let's say a user has uh add added three to four items to the checkout and he left the website and then you can send user hey you left something a user can see all of his checkout items you can do some type of tracking and analytics you can do authentication like cookies can help with authentication and security by storing tokens or other information that verifies a user identity you can use load balancing State Management and cashing stuff with cookies now I'm going to implement the cookies in NS project you got to install these two packages I have already installed them I've already installed in my package.json file this is the cookie parser you need and then you also need a typing for cookie parser go ahead and install them all right our next step is to register a cookie parts sir in main.ts file this is our main entry file here I have registered a cookie parser you can import it as a star and here if you want to add add your secret you can do it here or if you want to add uh some logic or decode something like that this is the option from a cookie package you can go to cookie parser so this package is similar to this one this one cookie parser but you can look at the documentation what type of options you have now our next step is to set the cookie I'm going to create a new route to set the cookie and we need a response from the nestjs comment and response type from the Express package here I'm allowing the framework you can set the cookie I am I'm going to set the cookie cooking token name encrypted cookie string something here it's a key value PA here and I'm sending a message cookie saved successfully here here I'm trying to log all of your cookies and return cookies in the get route now we need to test the application when you look the app controller here let's say I'm want to set a new cookie I've already saved that cookie in my application when you look at the Local Host colon application tab here we have the cookie let's say I want to set a new cookie it should be let's say a user token or authenticated token something like that JWT or JWT encrypt something like that yes jw. iio so what I want to do I want to so let's can I do that let's add this payload here or you can say I want to add a user ID let's say token I'm going to add a user ID let's say a mongod DB ID or you can say user ID so let's send the request from our browser to first set the cookie so I can set the request please set the cookie cookie saved successfully and you can see your user ID here this one but it did not encrypt but it did not save as encrypted you have to save your encrypted value here let's say I'm going to copy this token and you got to paste it here now I have an encrypted value so cookie saved successfully what if I try to get the cookie get all of my cookie it is going to give me the user ID and cookie token name that's how if you want to implement cookie based authentication you can do that if you want to implement High intent intensive task then you need cues High intensive task mean sending emails generating reports processing images or any task that can be offloaded from the main application flow with the help of cues you can manage in process task in the background without blocking the main application execution so you can use cues in task generation when you you identify task that can be processed asynchronously let's consider sending an email after a user register instead of sending email directly with the registration endpoint you can push the task of a sending email to a queue so this task is executed in the background separate from the main application thread this this ensure that the main application remains responsive and does not get blogged by the time consuming tasks so if you have highly CPU intensive task then you can use qes let's dive into the implementation of cues in nestjs nestjs provided the bull package they have written their own implementation by using the original bull package you have to install the package first I'm going to install the nestjs bll I also need to install npm B npm install B the simple bull package nextjs pull is using the redish under the hood so you need radish caching Library make sure you have Docker in your system we're going to use Docker to pull redish image I'm not going to install redish separately so that's why I'm going to use docker now let's create a new module our application what we want to do we're going to create a fake implementation to convert do wave audio file to MP3 we're going to write fake implementation let's say you have a use case where you want to convert do wave file to MP3 or you have an application where you need this functionality you want to convert video MP4 to MP3 in that case you need a q let's create a new audio module we're going to write implementation here to convert do wave file to MP3 then we need a docket compose we're going to use redish image now we're going to set up Ries in the docket compose file let's create a new file inside the root directory I'm going to do it here docket compos yl let's rename it to yl so we have to in start the docker compose my Docker is running now let's install Docker compose up it will pull the redish image from the docker Hub but I have already pulled Docker radish image so my radish server has started I think I've already installed another extension to work with redes if you want you can install that here you can see the redis I have installed this one database manager for my SQL Maria B post sqlite and redis here you will see the database if I try to create a connection for the redes Local Host 6379 that's my port so I can connect now now you will see all of my databases so this is my current or the latest I'm going to delete the rest of the other now I have the empty let's remove everything let's connect so I have the audio que so get rid of this one now we have the empty data SP now we need to register a bull module so in the app module I'm going to register it here your module and I'm going to do it here make sure you imported a bull module bull module import from Nest CHS SGS Bull and bull module so I'm going to open a new tab to run my application next we need to register a queue inside the audio module you will find the audio module here so we got a register it here make sure you imported the bull module and I'm going to copy that and let me paste it here so this register Q This method is used to register a queue with your within your application it takes an optional object as an argument to configure the que we have provided the name of our Q audio q and this is the name you will see the name here here it should be the audio Q this one where is my redish yep you will see the audio queue here let's move forward now we're going to create a convert end point I'm going to copy that into audio controller and I'm so we have audio Q let's imagine we would like to convert v file into MP3 this is my I'm just writing the fake implementation we are not writing the exact logic to convert the file but you can do that this is just a file name this is an optional object so this will add a new entry inside the Q so we have injected the audio q i got this Q from from The Bu package the type now we need a processor to process the queue let's define a new audio processor audio. processor. it would be a service or provider so we got to register it here inside the providers AIO processor so here when you want to process this when the application wants to process it is going to call this handle convert this job will take this argument as a job here inside the audio processor so I'm just trying to do the log here let's run the application to convert W file to m B3 we have to send the convert request so in the HTTP client I'm going to send the post request convert let's say dot v file to MP3 post HTTP Local Host Callum 3000 SL audio SL convert I don't need to provide any argument but if you want to provide argument or or request body you can do that now you can see it has run successfully I got this message starting wave file inside the audio processor here starting start converting v file to MP3 and I got the object which is sample. W file which which I have passed here whatever you pass here it will be received here inside the job. data and finally it has completed this one if you have any type of logic to convert P file to MP3 you will Implement here here but what if I look up the database do you have this one convert yep you can see the bull and we we have the audio Q this is our message I can show you here you can see the name is convert which we named here the convert this one q key key is here convert convert and the data is sample. W file and all of these metad data what if I provide additional data let's say ID which is one so it is going to save also ID let's run the request you can see I got the file and ID and Let me refresh it I'm going to connect uh you can see file sample do wave and you can see the ID the name is convert and the audio CU which is we have named here here inside the audio module this is the audio Q in this lesson I'm going to teach you the event emitter in nextjs event emitor is a mechanism that allows different parts of your application to communicate with each other and even driven approach so you can learn more about you can do communication between module Services components or classes under the hood nestjs uses event emiter to collaborate with these services and modules and components so an event emitter works with Publisher and subscriber pattern if you heard about this design pattern or you have used this design pattern now we're going to talk about some practical use cases of event emitter you can do module communication you can send the notification system we're going to use this use case in the previous video we have converted wave file to MP3 now I want to convert I want to send the notification if the file has successfully converted we need to send the notification to the user we can also use from for Real Time updates if you have any plugin syst system you can do with the help of event emitter you can achieve logging and monitoring you can do error handling and Reporting this one is also useful you can Implement in user authentication and authorization for example authorization service could emit an event when user logs in and other parts of application can respond Accord accordingly let's say user has logged after 10 days your you can your system or your application can have notification you can also Implement in the caching and management in our case we're going to take example from our previous example let's say you want to send the notification when w file converts successfully into MP3 format you can use event emitter to send the notification you got to install the package first nestjs event emitter and Next Step you got to register the event emitter in the app module let me change my Branch here event emitter Pro we got to create install event emitter again because I was in a different branch let's install it we have event emitter let's register it in the app module I'm going to do it here we have to import the event emiter module I have to import it manually event emitter module from nestjs event emiter that looks good we have registered the event emitter module this will register all of your event listener or or create all of your event listener we will have audio converted listener it's a service it's a provider this we have just a method it will accept the event and the audio event we will create the type this is the name of the listener or the name of the event that's why I used on event here when you emit the event this audio converted event this function will be called we're going to emit this event in the handle convert in the previous video we used this method to convert fave into MP3 so when you emit this event this method will be called so you can have any type of logic here maybe you will have an email service and your email service will have a method to send email let's create a new file I'm going to copy all of the code this is a provider we're going to in we're going to create inside the audio converted what's the name of the file audio converted listener I can say audio do converted or you can say audio converted listener. so we have this file we did not create this type let's create this type in audio folder I can say audio actually we can do it in an events folder we're going to store all of the types audio converted event. it's nothing it's just a type for types typescript class it looks good make sure you register your provider in the audio module so audio converted listener now we need to import we need to emit this event in your handle convert we have done it in the processor while converted successfully and you can send a message make sure you have import or inject event emitter event emitter event emitter 2 from njs event emitter package njs event emiter oops event emiter I don't know why they use two so I'm going to use the same stuff two event emitter to and we have emit this event this one now we have to test the application let's run the application I think do I need a Docker let's run the application yes I need a Docker let's install the uh let's start the docker first because we were using redes when we were building this Q so this Q is dependent on bull module is dependent on rades let me start my Docker now my Docker is running now let's run the application to test this event emitor we have to send the API request to convert fa file to MP3 it should log the message actually it should run this event this meth let's send the request I'm not able to send the request why saying waiting I think I did something wrong here look at the audio processor or audio controller wa I think it is not calling this method or emitting this method emitting this IM event oh I think we did not stop part that is server let's do it I'm going to send the request connect with r so it has X executed successfully and I got the message notification has sent to the user that file is converted successfully so I also loged the event that looks good we have successfully achieved our desired use case here it has emited the event I also passed a data object from the Q job. data which we were sending from here so I received the same object inside the event listener here I received the same event here and here I locked the event the first one is the event and the message notification has sent to user successfully this is how you will Implement event emitter in nestjs in this lesson I'm going to teach you the streaming in sjs streaming is the process of sending or receiving data in small chunks called streams rather than sending or receiving the entire data at once the concept is based on stream API in nodejs and is utilized for more efficient data handling especially when dealing with large amounts of data such as files Network request or realtime data Transmissions you can use streaming for file upload and file download you can do realtime communication if you have to build a media streaming type application like Netflix then you need streaming API API responses reading and writing from stream when processing data from sources that generate data incrementally such as reading log file or parsing large XML or Json documents you can do some data aggregation server sent events database operations proxy servers all of these practical use cases of streaming in this video I'm just showing you how to download a file with the help of streaming we need a nest controller a file controller here I will specify a a a method it will download the file from this crun project as a package.json file it is going to save in my computer this is another customized way to download the file when you download the file with this method it will download the exact package.json file here it will not download with extension only text file let me show you the difference between them let's create a new controller open the file controller let me import some dependencies and we need to use this method to download the file I'm going to create a new method here let's run the application let's try to send the request to the file file we have the endpoint file and the stream file file and stream file now it is going to download the package.json file you can see it is giving just only a stream file it did not download with package.json file if I open the file you will see it is nothing more it's just a simple text file in a Json format but we going to we want to download the exact Json file you can do the same stuff when you down when you want to download images or video you have to specify here the content type should be video or audio it depends on your use case and you also can provide the name of your file just like we did the package.json file you have to do it content dispo dis disposition now we're going to copy the same part method and place it here it will return a streamable file I have created the stream by you joining the path which is this one I'm referring to package.json file file and finally I'm setting the response by setting application Json my file name would be this one act as the attachment and finally it is going to return the streamable file now if I go to this endpoint file and/ stream file customize what will happen now it is going to do stream file customize. Json on not not it should be Json now it is going to see you will see the package.json file I already downloaded the package.json file when we were when I was practicing this I can replace that you will see the package.json file I have opened the file in my Mozilla Firefox you can see your the package Json file we have scripts we have all the dependencies and we have the dev dependencies this is how you can download any file if you have images you can specify your image format or you can name the file name or your image file name you can also set your image content type in this lesson you're going to learn this session in sjs session refers to the concept of maintaining stateful data between consecutive request from the same client a session allows you to send allows you to store and retrieve user specific information on the server server on the server across multiple request typically using cookies to identify the session if you have used session based authentication in your project the concept is same you can use session to maintain the authentication state of a user when a user log in logs in session can be created with their authen authentication data and subsequent request can be authenticated based on the session you can use session in authorization user preferences shopping cards user tracking caching personalization and form data persistence we going to use the express session let's install these two packages I have already installed in my package.json file session Express session and the next package you need type of Express session then our next step is to register a middleware when you go to main.ts you got to register it here AB do session make make sure you import your session from the express session you can use any secret key you can also set resave you can read the documentation of resave what this resave is doing you can also read the documentation of save uninitialized you can find documentation here from the express session when you check a save or resave here you will find the documentation uninitialized initialized you can also find the documentation of uninitialized next we have app controller here I'm going to create a simple route to login let's say uh a user wants to log in when logged in successfully we have verified the user from the database then you can set the user into the session I have set the object ID and the username and when later user wants to access his profile he can do that because we have saved the user in the session so here if there is a user in the session it is going to return user else not logged in you can test it simple by sending the login request it is saying a user has logged in just like we did just like it did if I said if I try to retrieve the profile it is going to give me the profile because we have set that user when we were logged in this one now I got this hello with the user and the name this is how uh if you use Json web token we basically stored a Json web token in the storage but if you want to use session based authentication on front end you can do thatlearn the fundamentals of nestjs by building the back end of a Spotify clone nestjs is a framework for building efficient scalable node.js web applications you'll learn how to design a database create rest apis and deploy the apis to production how did Alie develop this course welcome to my course nestjs let's talk about what is nestjs nestjs is used to build server side application in node.js it is built on the top of node.js expressjs and typescript the major difference between nestjs and other nodejs framework is this framework is using typescript and it is using the angular architecture angular Concepts on the pack if you familiar with angular concept you can work with nestjs is very easily why they are using the angular concept because if you use the angular architecture Concept in the back end you can organize your project in a easy way the development would be easy the contribution for other developers would be easy in sjs look at the documentation you will find the controllers providers modules middleware exception filter pipes guards inter interceptors and custom decorators all of these are Concepts in angular why they created nests if you have worked with Express you don't have any structure like you don't have any best practice to organize the backend project so they created the structure architecture level they designed the architecture to build server side applications in nodejs and typescript under the it is using expressjs and typescript so they are just solving the architecture problem when you build the large application in nodejs we backend web application in nodejs when your code base is increasing day by day it's hard to follow specific architecture that's why they have created the nestjs if you follow the nests you will see hey we need a controller we need a provider we need modules we can break application into multiple modules we need a middleware we need exception filters so this is how you can architect your backend application this is exciting project I'm going to share you all of these Concepts in this course let's create a new project in njs first of all you need to install ljs globally on your machine I'm going to install nestjs CLI this this command will help us to generate nests project my CLI has installed now we need to create a new project you can use this command Nest new the name of the project you can choose any name here I just use in fundamentals dpro I'm going to use npm now it is going to it's going to install all of these packages for me now my project has created successfully so I'm going to navigate to my project directory this is end fundamentals Das Pro now I'm going to open that into my code editor I'm going to use vs code so when you open the package.json file you can run your project in development mode by using this command npm start Dev npm Run start D you can see my project has started successfully uh by default njs uses 3000 Port you can verify that from the main. file I'm going to go to the Local Host call in 3000 let's see what will happen you can see Hello World so our project is running fine now in the app controller you will have a simple message the simple controller method it's a route get hello and you will see the hello world here hello world or you can say hello I'm learning nestjs I saved the application it has reloaded successfully let me send the request again you will see hello I'm learning njs so this is our source folder you will place all of your Source folder source code inside the source folder this is our main.ts file when you run this command npm run Start Da njs is going to call this bootstrap function and inside the bootstrap we have a factory function and we are initializing the app module this is our root module in here we have set the port we have the service we have module controller and the test file for a controller this is our module remember this is the angular structure and each module is consist each module consist of controllers services and providers you can import multiple modules here we have the service and uh you will place all of your spec file inside the test end to end test should be uh saved here and unit testing you unit testing files will be located here this is eslint RC rules for eslint prettier n if you want to customize the nest C nestjs project you will do inside the nest CLI we have package.json file we have TS config and TS config build this is used for typescript configurations let's talk about the concept of module in njs in njs each module is consist of providers controllers imports and exports so this is the building block of nestjs application you can read my notes I have provided you the PDF documentation nest in providers nestjs are classes that act as a Services factories or repositories if you have worked with angular you know the providers so you can encapsulate your business logic and it can be injected into controller or other services so controller serve as the function of handling HTTP request whenever you create a new endpoint you will register it inside the controller I'll teach you more about controllers in the next video Imports is an array specify the external modules needed for the current module you can import other module let's say you have break down your application e-commerce application into multiple modules you have post module you have products module you have ERS module you have users module let's say a user module can use the product module this is how you think in terms of modules if you want to export you can also export controllers and services from the current modules so each nestjs application will have a root module just like in angular root module serve as the entry point and is responsible for instantiating controllers providers and other core elements nextjs follow the module isolation principle ensuring that application is organized into distinct functional or feature based modules so you will have root module app module let me check the application you will have the app module you can see that you have Imports array this module has app controller and app service let's say we're going to build a back end of Spotify application we can divide our application into multiple modules you will have a root module and I'll have the artist which is feature module and we will have songs module to handle the songs functionality we have o module to handle authentication these three are all the feature modules SS modules are a functional organizational unit that follow the modularization principle it helps to do code free usability and separation of concerns principle under the hood they have implemented the principle design pattern to organize your code that's it let's create a new module I'm going to create a song module you can use CLI Nest G4 generate in the name of the module which is the module keyword I want to generate the SS module here you can provide any name I'm I'm interested in the songs module so you can see in the app. module it has added the entry automatically for you in the Imports array and you can see you have a songs module that's it so this songs module will have controllers providers and imports and exports array controllers are responsible for handling incoming request and sending response back to the client we are building the Spotify clone application let's imagine or let's say you want to fetch all the songs or you want to see all the songs of Martin gck artist your browser will send the find all songs request to the nestjs application inside the nestjs application you will have songs controller inside the songs controller you can see we have find all method the find all method will be called and this method will fetch the songs record from the database and send respon response back to the client similarly you can send the same request from your mobile application so controller will be responsible for handling request and sending response back to the client you can create a controller very easily all you need to do is controller decorator and inside The Decorator you can provide the prefix route prefix if you want to define the request Handler inside the controller you have to use the HTTP get decorator if you want to create the post endpoint you have to use the post decorator it's just returning a simple string message fetch all the songs and this method will be converted into this API endpoint Local Host callon 3000 / songs we are going to build these API endpoints to fetch all the songs to fetch a single song I created these routes to create a new song to update a song on the based on ID and delete a song on the based on ID I'm using the rest client extension to send the API calls it is similar to The Post men if you don't have rest client you can find from the vs code extensions and find the rest client the rest client package is saying You must have a file with HTTP I created the HTTP extension now my application is running at Port 3000 my development project is running at 30001 you should not aware you should not care about this project we are building project on Port 3000 if I send the request to fetch all the songs we don't have any rout yet it is giving me the warning message or error 44 you don't have all these end points I want you to accept the challenge and start building these end points we don't have any controller let's stop the application and I'm going to create a controller songs you can see that songs controller has created inside the songs folder we have spec file testing file and controller. TS file this is the controller decorator this is the prefix one more thing it has added the end entry in the controllers array now let's create the request Handler first of all I'm going to implement the get find all it is going to return a simple message find all songs let's restart or run the application you can see that our application is running now let's fetch all the songs I got find all the songs find all songs endpoint it means we successfully created the route to fetch all the songs now now I can send the request to fetch the songs watch all songs end point let's create a single song endp point you have to use the ID as a dynamic parameter I can say find one here I can say fetch song on the based on ID similarly we need update put for update I'm going to use the put HTTP verb update update song on the based on ID we also need delete I can get the delete from here let me replace the update to delete delete song on the based on ID and finally we need a post endpoint to create a new song I can say the post create create a new song so we created the CED API end points now it's time to send all the request it's working fine now create a new song endpoint update song on the based on ID delete song on the based on ID now you got the basic understanding of controller and how to create route in njs application let's talk about Services services are providers it means you can inject into another class it will be treated as a dependency we will have a service and the service is responsible for fetching data from the database and saving data to the database if you have to interact with database you have to write the source code inside the service you will create a method to interact with database we will use repositories don't worry and this service can be injected into controllers if you have multiple controllers into module you can inject the same service into that controller or multiple controllers you can also export the service from a current module and you can use that service into another module we will have the song service it's nothing more it's just a class and all you need to do is to injectable decorator it means you can inject as a dependency into another class this is how you will inject the service into controller or into a class you have to inject it in the Constructor it will be treated as a dependency for the songs controller now the songs controller is dependent on song controller is dependent on the song service let's create a new service I'm going to use n CLI to generate a service let's write the name which is songs it will create a class and it will inject into our songs module you can see that we have the song service spec file which is testing file and we have the surver we we have used the injectable decorator one more thing it has registered as a provider inside the songs module I told you services are provider providers could be factories helper function you will learn more about dependency injection in more details in the later mod so I told you service services are responsible to interact with database right now we are not going to interact with database we'll use the postris SQL postris database in the later videos for that here I'm going to create a local DB which it should be array local array saving saving record in the disk private read only songs array I'm going to create the empty array let's define a new method to create a new song and it is going to return let's push the song make sure you get the song from the create method there is a method push and I we need we need to provide a new song and let's create another method find all and and it is going to return a simple array this. songs and I can return this. songs array so we have created two method now it's time to inject this service into the controller I want you to do it accept the challenge and do it all right I'm going to do it for you song service now inside the create I can use the song service by using the this this do song service please create a new song I'm going to provide a dumy name Animals by Martin you can choose any name don't worry we will create a separate song model and separate interface for the song let's call the return and for the find all I am going to use this do song service. findall let's run the application our application is running let's send the API request to create a new song you can see I got a new song if you sent all the songs request I got all the songs let's save another song you can see I got five songs let's fetch all the songs I got all the songs so our service is working now in the real world application we will write the database code code here here save the song in the database and here what we will do fetch the songs from the DB but we will implement this feature in later videos in this video I'm going to teach you how to validate the request body when you send request to the Local Host call in 3000 3000 SL song we are trying to create a new song but let's say if I miss the title field it is going to give me the validation message the title should not be empty and title must be string let me REM know the artist now you can see title should not be empty and artist should not be empty so I would like to add this validation to our create new song API endpoint when you go to the Spotify if I click on any song this is the title of the song and this is the published date or release date and this is the duration so we're going to pick title duration and the date of the song let's do it this time I'm going to use class validator let's install the class validator package and we also need class Transformer you can see both packages have installed nexts provide validation pipe you can use validation pipe for specific controller method you can use it here or you can use it here it's your choice but but I'm going to create a global I'm going to register it as a global so I can use in any controller so you can call use method there is a method which is use Global pipes nexts already created the validation pipe you don't need to create it again I have imported the validation P from next sjs common package and now if you don't have dto which is data transfer object you have to specify the network data transfer object properties let's create a new song create a new file create song d. now we need to add decorator paste very adds let's create a new class and I'm going to name it to create song dto the first property is title I'm going to make it read only and we have the second property which is artist array and we have another property which is release dat or you can specify the type which is string and the type of part is it's an array and we have the DAT there is another property which is duration we need to store the duration in the time format now I'm going to use the decorator from class validator the type of title should be string and it's a required property so you can say it's not an empty we can follow the same stuff for artist not empty it's an array it's an array and you can say type string let's add decoration decorator for release date type should be string and class validator provides a decorator is date string now we have for if you want to store the time or add the validation for the time there is a there is a decorator which is military time and it's also required property so I'm going to add is not empty so is date string if you want to apply that you have to add the date in this format and you have to add the time in this format now we're going to apply we have already registered validation pipe here and we created the data transfer object which is create song dto now I would like to apply this create song dto in the create endpoint you can register it or you can apply it by using the body parameter please apply it on the request body and I can say create song create song dto the type is create song dto and this time I'm going to push create song dto let's try to test it out and we need to run the application so we have to send the request or add the Json body in the response let me open the rest c. HTTP file and we need to add the Chason body let's send the request you can see title should not be empty title must be string artist should not be empty and artist must be an array so validations have applied successfully I can say let's say lasting lover the title and we need the artists s let's now we're going to test it out so we have this record if you will add the date in different format you can see dat should be valid ISO 860 date string for date string format if I do in this way you will get the error dur must be valid representation of military time which is hours and minutes so it's working fine now let's talk about the middleware a middleware function runs before executing the route Handler inside the controller songs controller I have the find all route Handler and the create route Handler if you if you want to run any function before executing the route Handler you can write your code inside the middleware it's a function a browser wants to fetch the songs before fetching the songs would you like to call any method would you like to run your logic would you like to execute any type of code middleware can have request object response object and next function it means you can customize the request object if you want to add header if you want to log the request time you can do that a middleware can execute any type of code you can modify the request object if you want to add the request header authentication token to the request you can do in the middleware you can end the request and response cycle you can call the next middleware function by calling the next method we're going to build the logger middleware let's imagine you want to send request from your browser to server before executing the route Handler I would like to log the request message or the DAT time let's implement the logger middleware it's a class we're going to build a class based middleware and to create a middleware you need to implement the nextest middleware interface it provides a use method and use method will have the request response and the next function here I'm just logging the request dat time and at the end I'm also calling the next function it will if you will not call the next function it will not go to the next step one more thing middleware it's is like a dependency you can inject into module it will act as a dependency here we are injecting the middleware as a dependency to inject the middleware as a dependency we need to implement the nest module interface it will provide the configure method and the consumer will be middleware consumer and we just need to call the apply method from the consumer object and you need to provide the logger middleware here you need to specify where do you want to implement the logger middleware I would like to implement for songs API let's implement the locker middleware before creating a middleware I'm going to use Nest CLI please give me the help for nest generate command you can see that I got all the commands related to Nest generate you can generate class controller decorator filter guard middleware pipe provider we also have other options like no flat please do not create directory or no spec please do not create testing file let's create a new folder common I'm going to place all my middle Wares inside the common directory next generate Mi common SL middleware and the name of the middleware which is logger and I don't want a spec file please do not create the directory let's try with no flat and dash dash dry run let's see what will happen dry run it will not create the actual file but got the steps you will get the understanding how it will run it's working fine now no files return to dis but when you EX cute this code it will create the logger middleware file inside the middleware directory that looks good so I'm going to remove the dry run let's write the file perfect we have created the logger middleware you can see that it has already implemented the nest mid middleware interface and I got the use method with these three arguments request response and the next function here you can customize the request object if you want to add your custom logic you can do it here I can say request dot dot dot new date whatever you want to do do to dat string so we created the middleware now I told you or I taught you how to apply the middleware I want you to do it in the app modle we need to implement the nest module you can see that I got the configure method and we need to call consumer. apply the name of our middleware which is logger middleware and we have the four roots or routes I can say the songs now we need to test it out let's run the application my application is running now we need to send the API request if you will send the request to the root URL which is Local Host colum 3000 our middleware function will not run because we applied the logic to songs route fetch all the songs and I got the the log here request log send the post request I got the request log send the put request or send the delete request I got the log there are two other options to implement the or to apply logger middleware I can say option number one consumer. apply logger middleware for routes please run for only songs path and for only run request method. poost it could be option number two if you send request get request to fetch all the songs it will not run if you will send the post request for the songs I got the request if you send the put you will not see the request log another option we have let's do it consumer zor dot apply logger middleware for routes you just need to provide the controller it could be option number three it depends on what use case you like to use now I can fetch all the songs and I got the request log which create a new song I got the request log update a new song and I got the request log this is how you will create a middleware did you think about the error handling in njs if error comes from your application code nestjs provide builtin HTTP ex exception so let's say error comes while fetching the data from DB but we did we did not add any logic to handle the errors gracefully let's imagine we got the error while fetching the data from the DB error in DB while fetching record let's imagine that when error will happen nestjs will send this error to http exception this is the built-in exception in nestjs let me let me send the request to fetch all the songs you will see the server error with 500 status code next s has sent this message from HTTP exception but you can use the exception in your controller functions let's say I can say or did you think about how can you catch the errors you have to use the try catch block I can log a simple message I am in the catch block and this is my error let's try to fetch all the songs you can see that I got the error message I'm in the catch block and this is the error it means we successfully got caught the exception but we want to send the useful method in the useful status code in the response I can not see anything here for that we need to use the HTTP exception I can say through new HTTP exception it's a class and we need to provide the message can say server error or whatever you want to say I can say server error and we have to provide the status code HTTP status provides a lot of status codes you can use anything whatever you want to do for me server error internal server error if you want to send the message or cause which should be the error this one let's try to fetch all the songs you can see that I got the message server error with 500 status code which successfully caught the exception but if you want to use different error message you can do that you can use forbidden status code it will work let's restart the application now I got it so we have the status code 403 instead of 500 I'm going to replace forbidden to internal server error this is how you will cach the exception in your source code if error will come from this service this this method TR cach block will cat the eror got it let's talk about the pipes in njs there are two use cases to use the pipes the first one is to transform the value here in our example application we have the find one method we are expecting the ID as a input parameter by default it is going to give me the string so I can use the parse int pipe to transform the string value to number here you will see the type of ID it should be number another use case for pipes are to validate the input parameter in the create method we will accept the input argument like song title song artist we will validate the all the input arguments by using the validation pipe let's implement this transform value in our demo application so I'm going to remove it let's start it again it is giving me this response in nestjs you get you can get the dynamic parameter by using the ram decorator Ram decorator and the name of our argument which is ID I'm expecting the ID and I use the template string let's define the type of ID I'm going to send the request you can see the type of the ID is string we were expecting the number type but nestjs got us the string type you can convert this string into integer or the number by using the pipe Pars in pipe that's it let's send the request to fetch the song on the based on ID you can see I got the number ID number type if I provide the string value here you will get the validation error validation failed numeric string is expected bad request error if you want to customize the error message you can instantiate it eror status codee HTTP status dot not acceptable now I got not acceptable if I provide the numeric string I got the ID which is number type of the ID is number we successfully transformed the string value to number value in the next video we will implement the input validation using pipe we will create the custom validation pipe you have learned how to inject dependency by using the Constructor based dependency injection pattern we have injected the song service into the song controller what what will happen when songs controller will inject or instantiate the song service let me open that songs controller here we are injecting the dependency song service and we have provided as a dependency here this one this song service when Nest container instantiate the songs controller it first looks for any dependencies in our case we have the song service when it finds the song service dependency Nest will create the instance of the song service and cach it and it will return it if already created the cache then it will return from from the cache it will not create the new instance let's imagine you are using the song service inside the multiple controllers the first controller let's say we have the songs controller I'm using it first time here if I use song service inside the song service dos back file it would be treated as a second time now the second time it will not create any instance it will get the instance of the song service from the cache this is the Singleton pattern applied here next under the hood created a Singleton single instance of the song service and it is going to share the same same single instance throughout our songs module but you're going to learn multiple scope if you want to use the scop scope strategy if you want to instantiate a new instance after for after every incoming request you can use the scops but I'll talk about the scops later there are many techniques to use the providers some of them are standard providers value Prov providers known class based provider tokens class providers we use that class providers Factory providers used Factory providers and nonn service providers we're going to play around with all these six techniques let me explain with the help of examples this is the standard provider inside the S module we are using it as a standard provider but you can convert the above syntax into this one let's use it I need to open my project we need to create a new Branch model 3 lesson number one open the socks module so we are using the standard provider technique but you can write the above syntax or above code by using this syntax I can say this is provider just this it now we have the song service and the song service please use it as a class when you inject it into another class we are using inside the class in injecting as a dependency now you can test the application I'm going to send request to any URL let's create a new song artist must be stream this is this true why artist I think so I got the issue in the create song d I did add the H should be true I'm telling to class validator the elements of the array type should be string each element of the array should be string now it will it will be working fine if we have three articles or three artist Martin and John you can see that it's working fine now so we also tested this syntax this is the standard provider but if you like this syntax you can keep this syntax but I just want to show you I'm going to this out uncomment this one now I got the song service now I'm going to talk about the value providers if you want to create the moing service instead of the original service you can do that with the help of use value the use value syntax is useful for injecting a constant value or you want to put an external Library into Nest container or replacing a real implementation with more object we are using this one we are replacing a real implementation of song service with Mo object so when you need this use case you have to use the use value or if you want to inject a constant value you can use the use value or if you want to inject external Library into the nest container you can use the use value let's do it I'm going to create a mocking object here we have a find all method inside the song service when you open the song service you will see the find all method but we have to return the songs I'm not going to throw the arrow would be song service and use value which is songs moing object Mo song service that is it now now we need to test it I'm going to fetch all the songs and this time you are getting the response from the mo object not original song service so we have the find all method and it is returning this one if I will app add the artist I'm going to fetch all the songs from the mo service object mock service and you can see I got the record from the mock service instead of original song service find all method we have learned how to use the use value now if you want to inject the known class based provider you can do that let's say I want to inject an object with connection we have three properties connection string if you would like to inject any object object as a dependency you can do it well with use value I told you you can inject constant by using use value you can object an you can inject an object or you can inject the working object let's create a new file with connection. file and I'm going to specify some connection properties you have to create an new constant. file inside the common folder and I'm going to add the constants directory here you will have constant. TS file I can say connection. and I'm going to copy the code I just defined three variables and I have Define the type which is connection now I would like to register it as a provider you can register inside the songs module or you want to register it to app module it depends on you provide this is the name or the token value this is how I will inject in the class when I will inject in the class I'll use this token key use value let me provide which is connection so we have to inject it inside the song service I can use the add inject decorator so songs controller I think I injected inside the song service so I'm going to inject here inside the song service or let me inject in the Constructor function here I would like to inject I can say inject let's provide the key private connection here we need to provide the type I have defined the type this is the type so I can log the connection this. connection if you will not add the private so you can add directly without adding the this keyword I did not add the provider so I access the connection string without adding the this so let's say this is I can say I'm going to use the template string this is connection string when songs controller will be instantiated this Constructor function will be called so it will log this message you can see we have this is the connection string so I can get the connection string now I can see this is connection string and I can say the connection string or you can say my SQL dot dot col do dot 1 2 3 6 or maybe Port I created the fake or dummy connection stren you have learned how to inject the object as a provider and used it as a dependency now we're going to talk about class based provider we have already used the class based provider here this one not this one this one used Class so I'm going to create a new service this this will be called da config service inside the dep config service I'll have one property and a one function DB host and get DB host remember it's an injectable service so you can register it as a provider inside the app module by using the use class syntax and you have to provide the name of your service in our case we have the da config service and and then and then I can use the dev config service inside the app service so I can create a providers hold up let's rename providers let's create a new class def config service.ts and we have these properties we have TB host in the get TB host so let me register inside the app module we have provider and I can say please provide Dev config service in the use class Dev confli service and and now I can inject inside the app module let me inject it here I can say private Dev config service and I can say def config service and I can call the method from the D config let me convert into the template string da config service. DB host so we have to send the request to the root URL to test it rest let me send the request hello I'm learning NS fundamental and this is the DB host which is St config which is Local Host DB host so if you want to inject the known service provider like a simple object and you want to inject Dynamic value you have added the check or if condition if node development equals to development then you you have to inject the dev config otherwise you have to inject the pro config if if you have two objects and you want to inject on the based on condition this is the known service provider it means these will not be classes if you have this type of use case you can inject by using the use Factory so I'm going to call inside the app module let me let me show the demo I just created the two object and in the provider we have used the key which is config and I use the used Factory and we have to provide the arrow function it's just returning a value Dev config and the pro config if you want to in inject dependency or inject provider only based on condition then you can use the US Factory and now the same way you can inject config value in the app service here we have to inject it by using the inject decorator provide the key which is config in private config we have Port value and type a string and you can say Port should be this do config do Port so we have to test it to send request to the root URL now I got the host which is Local Host and the port which is 400 so we have to add 4,000 you have learned how to inject provider as in the standard way you have learned the use value you have learned how to add non class based provider you have learned how to use use class provider how to use the dynamic how to in how to register the dynamic provider and finally you have learned how to how to register known service providers the previous video you have learned multiple techniques to register a providers when you register a provider by default nestjs use this scope default it means a single instance will be created which is called the Singleton pattern and this single instance of the provider is is shared across the entire application nextest cach the instance when application request for the second time it will not create a new instance second time it will return from the cash another injection scope technique which is request a new instance of the provider is created exclusively for each incoming request and we have the third technique injection scope technique transient providers are not shared across consumer each consumer that inject a transer provider will provide a new dedicated instance most of the time you need default scope because single turn instance is recommended to improve the performance of your application when you get the instance from the C it will give you the instance in the more faster way instead of creating the complete object it just give you the copy of the already created object so you can play around with injection Scopes let's say if you want to use it inside the song service I didn't I could not find how to debug the dependency injection so you have to use here scope injection scope what we have to say scope scope to transient the performance of your application will be hard it will decrease the performance but but it depends on your use case what are your requirements similarly when every incoming request if you have use case you want to create a new instance you can use it well for the requesting purpose for testing purpose I'm going to open the songs controller and here we have to say it's an object let's import this scope I'm going to send the API request it's working fine one thing you did not notice when I will create a new song it should add the song in the array so I have created three objects three songs object in the songs array when I will send the request to fetch a single song or all songs it should give me the empty response because on every request it will delete it the complete data complete songs because it will also re instantiate the song service inside the song service we we have the are we have the songs are you can see I created the song now when I try to fix all the songs it should give me the first song or all songs you can see the empty response in this video I'm going to teach you how to add one to many or many to one relationship between two entities where a contains multiple instances of B entity and B entity contains only one instance of a entity we have two use cases we are building this Spotify clone if you are using or you use Spotify each user has its own playlist and each playlist can have multiple songs so you as a user can store multiple songs or save multiple songs in the playlist so there is a one to one one to many relationship between playlist entity and the songs entity see similarly we have each user can have multiple playlist many playlist can belong to a single user so this is also a many to one relationship between playlist and the users let's create the playlist entity and add relationship we don't have any playlist entity go ahead and create a playlist entity I have created a new folder playlist. entity. TS file so I'm going to copy couple of the code from my notes we have created the playlist entity now we have to make make a relationship between songs and the users similarly type orm provides one to many decorator and this represents the target entity relation entity we are making a relationship with song entity this representing the inverse side of the relation in the song model we have a playlist property and we have the array of the songs I'm going to copy this code and I'm going to paste it here we don't have song. playlist open the song entity here we can add a relationship but we also going to add a relationship between user so I'm going to copy this code and paste it here now we have to add many to one relationship in the song entity so many songs can belong to a playlist for each unique user we have to import the playlist import many to one relation and finally we have to add one to many relation in inside the song inside the users user entity so I'm going to copy that code inside the user model and I'm going to paste it here now everything is fine now I have added many to one relation in the song it means it will have the primary key of the playlist entity and save it as a reference key or the foreign key now we need to create the clip playlist module I also want to create a new playlist I'm going to create a new endpoint but first of but first we need to register our new entity I'm saying to type orm please convert or make relation between playlist and the user playlist and the song every everything is fine now when you go to the pg admin refresh your tables you will see playlist table this is the playlist table and we have the user ID when you open playlist entity we have added the many to one relation it means it will have the user ID as a foreign key and inside this song entity we have added many to one relationship as for the playlist so this song will have the primary key as a foreign key of the playlist entity let me show you inside these songs we have a playlist ID relations have created successfully we created one to many and many to one now I want to show you how can you save a record with relation entities go ahead and create a playlist module you can use with n CLI to create a playlist module but I'm going to use my not notes playlists module. and I'm going to paste my playlist module we don't have playlist service and we don't have playlist controller I can create these two files controller. let's create playlist dot service. file I'm going to copy my playlist service we have to import couple of tip dependencies inject dependency and we need playlist we need a user we we need a song that is good right now also need to get the injectable we also need to import report osit Tre I don't have any user so import the user we have service right now and we going to create controller or we can build create playlist function I'm going to create a new method you can see that we don't have create playlist dto we are just creating the instance of playlist I'm providing the name of the playlist when you go to the playlist entity you have the name property each playlist can have multiple songs so I will get IDs of the songs from the request body we are using the same logic in the previous video we used here I'm setting the relation with songs entity I am creating the playlist when you are when you need to create a playlist you have to provide the name and you can set the relation for the songs and you can set the relationship for the user when we will implement the authentication I will not find the user directly from the database I'll get it from the logged in user we have set the relationship with user and finally we are saving the playlist we don't have create playlist D go ahead and create a playlist D we have used that logic I'm going to create a new file playlist dot or you can say it should be new folder dto inside the dto playlist create playlist dto create playlist do D.S we are expecting the name type should be string and I'm getting the IDS of the song from the request body that's why I specified the number type the array of the numbers and we have the user it should be a number it should be the ID and finally we have to use the create playlist dto we have to import it and now we have to build our controller function and the endpoint do we have a controller yes we have a controller everything is good to go I've have specified the playlist with this endpoint we injected the playlist service we have used that logic and I'm returning a simple playlist in the response we have to register the playlist module inside the app module and it will also be treated as a feature module just like we did with songs module we have playlist module now I have to test the application you can test it by sending the request do we have a user I already created the user in the previous video I can double check check it my users you can see that we have three users I would like to save the record for the second user with ID number two rest client we have to create a new playlist I can say create new playlist we have to send the post request Local Host column 3000 playlists content type is equals to Json application Json let's provide the data I'm going to create a new playlist with Feelgood now I would like to save the song with ID number six do we have the song with ID number six let me double check it yes we have the song with ID number six and this is our user let's say I'm going to say I'm going to create with user ID number two it's not a valid request now it looks fine we need to add a space here we have a playlist feel good now and we have a one song with ID number six and we have this user so this user has playlist feel good now and it has only one song you can double check it from the playlist this is the playlist record in this video I'm going to teach you how to connect nestjs application with type orm and post nestjs provide multiple drivers to connect with database if you want to use mongod DB you can also do that if you want to use my if you want to use post you can do that in this video I'm going to implement the post with nestjs uh typ orm is a object relational mapper you will write the code in JavaScript objects and these objects or classes will be converted into database tables if you want to write SQL queries you don't need to write plain SQL cury you can write queries in the form of objects first of all you have to install a couple of dependencies we need nestjs typ orm package and post driver and type orm uh open the package tojson file and you have to install these dependencies I'm going to add them here let me install all of these dependencies we also need typing for nestjs we have to install this package I'm going to install as a def dependency we already have this package types at node we installed these packages njs type orm post and type orm so now we need to import the type orm module into our root module in our case root module is our app module so we have to call this method from type or a module and you have to provide the connection strings or connection properties like type host Port username password database entities and synchronize whenever you will create a new entity you have to register it here for synchronize means whenever I will run the application please delete the data from all the all the tables synchronize please delete everything from the table but do not use synchronize in production otherwise you will lose the production data whenever you have to create a new entity you have to add it here inside the entities array so the for root method Sports all the configuration properties exposed by the data source Constructor from the type or a package I have installed PG admin if you don't have you can install the post admin I'm using PG admin 4 you have to provide your password let's connect with server we have to create a new database right now I'm going to create a new database Spotify clone this is my user go to the app module and we have to import the type type or module here we have have to install manually it's not giving me suggestion from Nest JS type orm and we need to get type omm module so I'm going to call a method type orm module do for root with we have to provide the options database which is Spotify clone host which should be Local Host and we need to specify the port for post gr I think 4 5432 by default username for me it's postcript add you have to provide your password for me I think it's root I specified the database name and we have empty entities right now I don't have any entity and synchronize set to true it will create the database tables po it should be usern name not a user so how can you verify we have successfully connected to type orm you can use data source object in the app module now you can inject it and I can log let's add private you can log anything from DB name let's say and I can get it from the data source dot data source. database this do I have that property let me check it dat source. driver dot database Let's test it out I'm getting the error wrong driver so I think I did not provide the type let's add the type the type of the driver which is post now we have made the connection successfully you can see DB name which is Spotify clone you can also check the songs table inside the Spotify Let me refresh it and I would like to look at the tables we have the tables I don't have any song because we did not create any entity right now but we have successfully connected to the postris database in this lesson I'm going to teach you how to create an entity entity is a class that maps to database table or collection when us using mongodb you can create entity by defining a new class and Mark it with an entity metadata and inside the metadata you can provide the name of the table in our case I'm going to provide the songs table name an ID which is the primary generated column the ID will be generated automatically it's an auto increment and we have the title I use the column decorator for artist array postris also Sports error data type you have to provide the column and I'm using the V character you have to say this column is an array type you have to specify the array should be true and we have a release dat property or release dat field in the database table I'm specifying the call colum decorator and we have and we are seeing this the type of this field which is State we also have time type in the post you can say we have the duration I specified the date data type in the post Cas you can Define the time I don't want to save extra date field here I only need Time Properties time related metadata and lyrics lyrics could be the long text that that's why Post sports text type if you want a long if you want to store a string with long content or long long length entity songs which is the name of the table and you can say I spec I have I I have specified the description for each field when you will create the entity you also need to update the lyrics in the create song datto we did not we did not add lyrics property in the previous videos that's why I use the lyrics it's an optional property it depends on the user does user want to add lyrics or not and finally we need to register the entity to the app module and then you can can test the application let's try to implement it go ahead and create an entity I can say songs or song. entity songs. entity or song whatever you want to call let me say what I called song. entity dots let's specify the class I can say song I can provide the entity the name of the table which is songs now we need primary generated column ID the type should be number and we have the title field let's specify the title column title type should be string and we have another column this time we have the artist array you have to specify it as a string array here I I can say the V character V character and the type should be aray and we have release date duration release date let's it should be date release date type should be date and we have duration type should be time duration and the date and finally we have the lyrics type should be text lyrics type should be string now we need to test this entity you have to add register the entity in the song in the entities array now it should create the songs table for us let me test it out from the PG admin refresh the tables I got the songs table with these columns ID title artist release date and the duration we don't have any record so let's update the create song dto and I'm going to copy it and I'm going to paste it here create song dto let's add another field the optional which is lyrics everything is fine now we have tested it in the next video you are going to learn how to perform C operation we're going to fill these methods update delete find one find all and the create this time we going to fetch and save data to the database let's perform cred operations type orm Sports repository pattern for each entity type orm provides repository and this repository has CR features like create create record update record find record and delete record repository provides the method first of all you have to register the type or a module as a feature into the songs module we providing the entity like these entities I would like to use inside the songs module and it it will provide the repository songs repository here then you can inject the songs repository to use songs repository you need to import the type or a module into songs module just like we did it here this this module uses the four feature method to Define which repositories are registered in the current scope we only need song entity that's why we use the we have imported or added the song entity now we can inject the songs repository into the song service just like we did we did it as a dependency injection please inject the song's repository and the type of the entity which is song and you can in you can import repository from nestjs type or M package now I told you songs repository provides scrud method to create delete update here you can look at that create delete fetch records from the songs table let's implement this create song method this time we don't need to add a record in the local DB you're going to save the new song by using the song repository. save method let's Implement here in the songs module we have to import type orm module as a feature provide the song entity I would like to use this entity into the songs model in songs module now you you are able to inject songs repository into the song service so I want you to inject this songs repository Constructor pattern songs Repository repository and I can provide the song type which is entity now you have the exess of crud methods so song repository provides this safe method just like you learned here it provides this safe method for first of all we have to create a new song and it should return a promise with song so I just created should say create song dto the type should be create Song D so I just created the instance from a song class I specified the title I got the title from D I got the artist from dto duration lyrics and release date from the dto and finally you can call Safe method this. songs repository and I will would like to call this safe method and provide a newly created song and it should return the object get rid of the songs array I don't want to use it we also need to remove everything from here now it's time to test this G method make sure you have called yeah it should use the up expression here in the controller let's look at issue here it should promise and the song inject the repository inject repository and we we have to provide the entity which is song so everything is fine you can test without a sync V by default it should return the promise HTTP let's create a new song we also need lyrics I'm going to send the request amazing we have a song you can verify from the database you can see that that I got the first record this is the lyrics duration and the release date now it's time to implement find all it's easy to implement the find all all you need to do is provide the return type promise with song array return this do songs repository do find that's all you need and in the controller songs controller you can also add promise with song aray let's fetch all the songs from the DB I got the array right now we have only one record now we need to implement the find one find by ID you can create a new method inside the song service and it is taking the ID as a parameter and returning the promise with song you can use song repository. point1 method and in the controller we need we need to pass the ID as a integer and return the song in the response let me open the songs controller we already did it I'm getting the ID all you need to do is return this. song. find1 here I can say promise with song Let's test it out by sending the request only the based on ID you can see I got the first record if I try to fetch the second record I don't have any record that's why I got the empty let's implement the remove method I'm going to create a new method inside the song service it's just returning nothing or you can say delete result you can use that and return here and we need to use this method into the songs control ER we have to call it this Do song service. remot and we have to provide the ID we did not pass the ID or get the ID as a Prem I'm going to use Prem decorator and get it here ID and it's returning promise with delayed result we need to test it out first of all let's create a new song to we have a song lasting lever two the ID of the song which is two now you can perform the delete operation I would like to delete this record so I got the delete result we have successfully deleted if I try to fetch all the songs no I think I deleted with ID number one so first record has deleted and we need to use the update let's perform the update record so we need update method I'm going to create a new method inside the song service we don't have update DTU data transfer object you need a tip you need a new data transfer object for update the record because when you update the record all the fields are optional but I can get update result from type orm we don't have update song dto we have to create it I'm going to create in the dto update song Das d. so this time we have to copy everything all the fields are optional all I did I copied the create Song D and put the optional for every title for every field is title should be optional so I can say instead of empty it should be optional it should also cre it here is optional is optional now it looks good so we have to use the updates s video now we need to implement the controller function songs. controller that we need to get the Prem and we need to get the body need to get the pram and update song dto and I'm going to call this do song service. update the first one is ID and the second argument is update song tto you have to import it the return type should be promise with update result that's it I have found the issue which is this space content type let's try to send the update request duration must be valid presentation now it looks good so you can double check it from the database this is the record with id2 we have successfully updated the record we have tested the application in the next next lesson you will learn how how to implement the pagination now we're going to implement the pagination I'm going to use external package to implement pagination in nestjs uh first of all you have to install this package I'm going to register it here and we have to install it and now I'm going to add a new method inside the song service this time I'm going to call it paginate and I'll use paginate method from nestjs type or M paginate and it will accept the pagination options like page metadata when you will fetch the record on the pation it should give me the items array and we have this metadata total items item count items per page total pages and current page these are all the options inside the options object and finally it will return the pation and we have to provide our model which is song and we have to call the page unit with song entity we have to provide the songs repository and the options if you need to add a cury builder like filtering or sorting you can also do that but here is our control rer function we use the Prem now we're going to use security decorator and it should name of the field which is Page you can add a by default default value which is one and I applied the pars int and I have added the default value and we have another field or another property and I'm getting it from the cury prams this is the limit and default limit which is 10 and I applyed the pars into pipe operator and finally it should return the pagination with song entity if limit is greater than 100 please do it 100 otherwise we have to specify the limit or tell or add the limit there is a page unit method we created inside the song service and you have to provide the page and the limit we're getting the page and limit from the cury so you have to test it by sending the cury parameter page which is two and the limit whiches to I want to see two records per page and I want to see the page number two if you want to add the Sorting you can also do that by using the query Builder please apply sorting on release date I want to see the latest song on the based on date let's implement it or you can Implement by your own first step we have to create a new method paginate and we need these options I can import all of these from the method so we have the pagate method now we have to call it inside the songs controller you can it depends on your use case but I I'm going to call the paginate method in the find all so I'm going to replace my find all method to this find all we also need cury Prem it's just getting the es lint warning messages we also need default value pipe we need pagination from nestjs that looks good we can test it this time I'm going to send the request to fetch all the songs it has applied the limit 10 and default value which is page which is one over the first page total items item count items per page 10 and total Pages we have one and current page which is one let's add another record new song to let's add another record new song 3 let's add another record new song four now we have four songs you can say I want to see the page number one this time I want to set the limit to two I want to see only two records per page we have the items array you can see we have only two records there are total two pages we are on the first page and items per page two item count two total items we have the four I told you if you want to add sorting you can also do that by using the query Builder inside the song service I'm going to add curil fer here and we have to provide cury Builder not songs repository we have to fix it cury Builder let's provide the cury Builder please create a new song with let's say a new Five song latest date it should should give this record first let's create it created a new song I got a latest song Only the based on release date it means it's working fine now in this video I'm going to teach you how to build one toone relationship between two models one to one relation where a entity contains only one instance of B and B contains only one instance of a let's take an example a user can become an artist or an artist can have only single user profile so there is a one toone relationship between user and the artist we don't have an artist model or artist entity first of all you got to create artist entity with primary key and then you have to create the user entity because we're going to make one to one relationship between artist and the user I'm going to have ID field or First Column first name column last name column email column and the password column for user entity now we're going to add one to one relationship type or provides one to one decorator to add relationship between two two entities uh in the first argument you specify the relation type I'm telling type orm I would like to make a relationship with with user enti this is the type of the relation you specify the relation entity type by following this syntax AR function and this join column will rep will create the reference key or a foreign key of the user entity inside the artist entity so we have so we will have a user ID as a foreign key inside the artist and finally you have to register the user and artist entity in the app module now we're going to implement these steps let's create the first a new Branch so I'm going to create a new artist entity if you like you can use CLI command to generate a new entity so I'm going to say artist do entity. file I'm going to copy my code there is nothing here you already learned how to create an entity and next we have to create a user model a user entity go ahead and create a new folder with user or users let's keep it to artist so I'm going to create a new entity user. entity. P the code we have ID field first name last name email and the password and now we're going to make a one to one relationship I would like to store the user ID inside the artist model if you want to store artist ID inside the user you can also do that it depends on your use case like I want to make a relationship here let me do it here we need one to one decorator specify the type of relationship by following the syntax we would like to make a relationship with user and here we will have the user and the user and I also need a join column that's it for now cannot find a module user. .ts file so we have to import it manually now it looks good and now we have to register these entities inside the app module we created couple of new entities please convert these entities into tables I can say artist and we have user our last step is to test the application and I have to run my PG admin let me connect with post this database so it has successfully let me check my schema which is 45 clone I have to connect it inside the tables we have the artist and the users table we have have the user ID inside the artist and inside the users we have for columns or ID first name last name email and the password our application is running fine now this is how you will make one toone relationship between two entities now we're going to talk about how to implement many to many relationship ship many to many relationship is a relation where a contains multiple instances of B entity and B entity contains multiple instances of a let's take an example many artists can publish many songs and multiple artist can belong to one song or multiple artist can publish multiple songs we have a multiple many to many relationship inside the artist nestjs or type orm provides many to many decorator this will specify the target relation entity and this is the inverse side of the relationship and it will have the songs array and on the song we will have the artist array we have a many to many decorator the target entity in the song we have Target entity which is artist and the second argument specify the inverse side of the relationship inside the artist we have songs property that's why I can access the artist. songs and inside the artist entity we have song. artist that's why I can access the artist from this song entity song. artist that is the inverse side of the relation when you set the casc to true it means you can create or update the record while creating a new song or an artist I'll teach you the benefits of ask getting when you implement the many to many relationship you you need a joint table many to many imple uh relationship always work with third table which should be joint table and I rename it to songs artist and this songs artist will have primary key of the song and the primary key of the Artist as a foreign key and we also need to refactor some create song dto instead of using EST string EST string we going to we are going to get IDs from the request parameter IDs of the artist and IDs of the artist in the update song video and then you have to register the artist entity in the songs module that's because I want to the artist repository inside the songs modle and finally you need to refactor the create method we're going to get artist here the first step we are going to get this artist IDs from the request object or request parameter or the request body and then we will find all the artist only based on IDs and finally here we are going to set the song do artist equals to artist if you have set the casket to true just like we have done it done it here cascading we set to true now it will set the relationship between songs and the artist it will automatically create the record with third table which is the joint table here here it will create a record it create records in the songs artist table by by setting the relation with this one songs. song do artist should be artist and finally we're going to save the song in the using song repository and you can test the application now um let's implement it first so we have many to many relationship I'm going to add this relationship in inser the artist I'm going to do it here this specify the target relation type and we don't have we we did not create the song. artist inside the song entity now we have the songs array let's import many to many I'm also going to implement it here many to many decorator the target entity in our case it's an artist and it's going to take the artist let's specify the inverse side of the relation artist dot songs and we will have join table I'm going to name it to songs artist or artist song let's take it the songs artist and finally I'm going to specify the artist array duplicate identify yeah I don't need this type because I'm not getting the string array from the artist instead of I'm getting the array of the artist from the request parameter we added many to many relationship inside the song model or song entity and we forgot to set the cascading to True here you can do it inside here G SC to true now we need to refactor the create song dto I have to refactor from it should be number and the first argument is an empty and and it looks good similarly we have to refactor the update song dtoo it should be number array of numbers the first argument is empty looks good now we need to register the artist entity inside the songs module so we can access the artist repository inside the song service I I'm saying to type orm I would like to access the artist repository inside the songs module or the song service that's why I have to register it here and finally we need to refactor create song I can say create uh inside the song service so you can do it too if you want here we have to find all the artists on The based on ID then we have to set the relation with artist and songs so you can do it but first of all we have to inject the Repository which is artist I can say private artist repository and repository I can say artist let's get all the artist you have to add a Sync here this do song artist repository find by IDs I can use that method provide the artist ID from the song dto artist now I can set the relation with song. artist it should be artist so we have set the cascading it will create a relation many to many relation with songs and the artist now it's time to test our application rest client here we have to send the post instead of artist we need to send the IDS of the artist a user can become the artist so we don't have any record in the artist and the user model you have to create it manually so I'm going to refresh you can see we have the third table which is songs artsts is not artist we have to fix it inside this inside the songs entity here we have to fix it this I'm going to refresh the table get it off this table you can drop it delete or drop yes now we have song artist with song ID as a foreign key of the song model artist ID we don't have any user right now I want you to create it manually let me do that I'm going to add a new record with ID one it should be Jane or saga Saga gmail.com I'm going to add anything here pass password let's add another user I can say Jane and I can say do Jan at gmail.com password 1 2 3 4 5 now you can save the record so we have two users right now if you want you can also add another user or artist I can say Martin gar Martin at gmail.com 1 2 3 4 5 let me save the record so these two users are the artists but we need to make a relation inside the artist table let's add a new record with ID and here we have to add a artist ID let me double check it yes one and the three one we have to add another artist one the ID should be three so these two are the artist ID should be here we have to set the ID should be two now it looks good so what I'm saying that a user with ID3 is an artist a user with ID one is also an artist so one Martin and seag are an artist and Jane is a just a simple user so when you create a new record I can say let's add a new song so these two are all the artist they are going to create they have created a new song I can say you for me that is it right now I'm going to send the request sounds good we have a new record title this is the artist ID this is the complete artist so we have an art ID one and we have the relationship let me double check it from the artist and the songs it just created a single record it did not get the ID 1 and three I don't know what is wrong with it let's do it here one and three you for me to again I am getting the ID only one let's log the song d. artist 1 and three then what why 1 and three it looks good maybe the issue with here console.log so when you look at the artist record oh we have one and the two so one and the two instead of 1 and three let's provide the two you and for me three now I got the artist ID one and the two it will also addit a relationship here inside the songs and the artist I'm going to find now you can see that a song ID with 10 has two artist these two users user ID number three and user ID number one in this video you're going to learn how to implement this signup functionality a user can create an account in our application and we need to save the user in the database first of all we have to install dependencies I'm going to use bcrypt JS password bcrypt JS package to save the user password in encrypted format I don't want to save the password in plain text like 1 2 3 4 5 we have to save the password in encrypted format that's why you have to install this dependencies let me open my package.json file I'm going to add a new entry let me copy it and I'm going to paste paste it here we also needed to install the typing for typescript I have to add the typing in the dep dependency I'm going to put it here so I'm going to run npm install please install dependencies for me you can see two packages have installed added new two packages now we have to create a user module and the Au module we don't have a user module and Au module inside our application I'm going to use nest CLI to generate a new module I can say o we have created a new o module you can see that we also need to generate the ser service for art you can see that Au service has generated we also need controller I can say AU an au controller has created it has also added the entry inside the controller's part we have it has automatically imported Au module inside my app module here is the O module now we have to create the users module one more thing we did not export the odd service yet here I I can say I would like to export the Au service it means whenever you will import the Au module into another module like we have imported the Au module into app module it means I can inject the OD service inside the app module that is why I exported the OD service let's create the user module I'm going to create manually users. module. TS I paste it we don't have user service yet we have to create the user service let's use the nli a user service has created we have to import the users module inside the app module so we have the user service and we have the user module I've also added the type or a module and registered the user entity because I would like to use the users repository inside my users module I would like to inject the user users repository into the user service now we have to register a new route inside the O controller we're going to register the signup and the login route inside the O controller we don't have a user dto yet but we do not we also don't have a user service do create method I want you to create the user D you first I can say I would like to add my DS inside the dto folder create user. dto file I'm going to paste my code we are expecting the first name last name email and the password from Network request this is the network data request object now we got to create the create function inside the user service it is saving the user inside the database do we have a user entity now we got to do it inside the user service here we have to add the logic we need to inject the user repository I've already told you how can you do it I have created the create method what this create method is doing remember we have installed bcrypt JS package let's import it first I don't want to copy the code inside the Constructor function now it looks good we have to import it first create BPT package here we are just injecting the user repository we are generating Assa it is nothing more it's just a number we need a salt to encrypt the user password there is a hash method inside the bcrypt library and we are using this hash method it is going to return the promise first you first argument would be PL text password we are getting the plain text password from the network request and this is our salt and finally we are just saving the user depository user inside the repository and we are deleting the password it's an extra remove them I don't want to send the user password in the response that's why I have deleted deleted the user password and finally we are returning the user from the response in the in the response we have called the user service. create method here now it's time to test the application one more thing we have to refactor a little bit our users entity I'm going to make it to Unique should be true because because email should be unique for each user and I don't want to save the pass I I don't want to send the password in the in the response it is saying that when working with type orm there might be cases where you want to exclude one or multiple columns field from being selected that's why we have used the exlode now let's run our application and we have to save the user we're going to send this request HTTP we have to send request to this route because we created this odd /up route we have to provide first name last name email and the password now we're going to test it out I have caught the error if user service is a provider if user service is a provider it is is it the part of au module you should learn from the error inside the Au module we have to import the user module because I am using the user service inside my o controller or inside the a service let say user module here we are injecting the user service inside the O controller everything is good to go right now we have to test our application what I would like to send the signup request let's create a new account I got the error 500 internal error duplicate key value Violet unique key do we have a user inside our database can say John one two still we are getting the same value same error cury failed error duplicate Cube value viate constraint we have changed a data entity and the table we have to we have changed the database Act I have added two new entries unique constraint and the exclude so we need to drop our schema and let me do it I cannot drop we did not use migrations at the end of this module I'll show you how to use the migration whenever you need to update a database you have to create a new migration what I want to do I want to disconnect from the database Spotify clone now I would like to delete it is used by some other let's use another database I can say one I found this is the shortcut to handle this error because we did not use migration so I can say that now I got the data from scratch where application is running fine now let's sign up you can see that it has resolved the issue the issue was with database update I got a user when you go to the Spotify clone one get rid of this one Spotify clone one and we have to go to the tables inside the users we have a de cord email john1 12@gmail.com and this is the password in encrypted format in this lesson you are going to learn how to perform login request when user sent the login request we have to verify the user from our database we have to decrypt the user password and compare the user password we're going to implement Json web token authentication a user provides the credential like username and password to the server then our server will generate the Json web token and send back to the user it will have the header payload and signature don't worry I'll teach you everything when client reive the Json web token if you are building front-end web application you can save the Json web token in the local storage when user want to receive or user wants to receive protected rout he must need to provide JWT token in the request header and server will receive the JWT to token from the request header and it will verify or validate the token if token validated successfully it will allow you to access the protected route you will learn how we are going to implement Json web token authentication we're going to use passport passport strategy or passwort package you have to install these two packages I'm going to install it in my dependencies we have to run npm let me hold on we did not create a separate Branch module number six lesson number two now we have it npm install we have installed two packages the next step we have to create a login route I can create inside my o controller let's create a new login route we don't have a login D yet we also don't have a login function inside the OD service yet let's create a login function inside the OD service au. service here we have to create the log function and we also need to get user service as a dependency let's create a new method first of all we are trying to find the user on the based on email if user found it should give me this user let's complete this step first we have to find the user we did not create the find one method I can say that inside the user service let's create a find one method it is going to take the partial as a user and we're getting the email or we can let's try to use the login dto login dto if it did not find the user it should return the unauthorized access we have to find the user only based on email we don't have login dto let's create a login dto inside the AU dtos I can create login. D.S file so we have the login dto I got the email we also need to import login dto we also need to import user entity and it should return the user that's it now the second step is we have to compare the user password inside the OD service the second step we have to compare the user password I have to import the bcrypt import Star as bcrypt from bcrypt now I can compare the password with plain text password and user encrypted password if password matched then we have to return the user and delete the user password if password did not match we have to send unauthorized exception that is it right now we did not inject private Au service now I have called the dto login method and provided the login dto let's try to send the login request rest client. HTTP we have created a user with John 12 John 12 run the application let's send the API request to login user it should be 3,000 not a 3,000 one we successfully got the user back in the response let's say I'm going to provide the invalid email I got error cannot find user if I provide the invalid password I got password did not match and unauthorized it's working fine now but our goal is to send the Json web token when user made successfully login request it should send the Json web token in the response in the next lesson I'll teach you how to create Json web token and how to send the Json web token in the response we have found the user on the based on email and we have encrypted the user password if user has logged in successfully we need to send the Json web token and when you will apply authentication on protected route you have to send the Json web token in the header we're going to use nestjs JWT package and passport JWT package and then we will import Port jwd module you have to provide a unique key you have learned how to create the login function and we you have to refactor it right now you have to send the access token you can create Json web token by using JWT service this is the provider you can inject it here as a service provider then I will move my constants into a separate file au. constants does and you have to register the JWT module and update o constant Secrets I also updated the expiry date of Json web token it will be expired after 1 day we going to have JWT service we are extending it from the passport strategy remember I'm using the nestjs passport package and we have passport jwd strategy here it is just extracting the token from the header we are checking the Json web token expiry date or expiry validation or expire duration here you have to provide your secret key which we have saved and then finally we're going to have validate method it is returning the user ID and the email when you apply the oard oard JWT oard will call this validate function you have to register the JWT as a provider then this is how you will Implement authentication you got to create a guard it's like a middleware in expressjs if you want to implement role based authentication you need guards we have jwd odard it is extending oard from the passport if you want to add your own custom logic you can do it here this is how you will make your route protected by using the gwd O card and finally you have to apply you have to send the authentication request like first of all you got a login login route will give you the Json web token then you can access your protected route like this is the protected route profile is the protected route only authenticated user can access this profile route so you have to provide the validation token which is this one Json web token in the authorization barrier it's a scheme and it will allow you to access the route so let's implement it first first of all we have to install a couple of dependencies here passport JWT nestjs JWT and passport JWT strategy I also need dep dependency which is typing of typescript let's do it here and we have to install the dependencies these packages have installed now you are able to use JWT module let's use inside the app module we have to register it we will move this constant into separate file but right now I'm going to do it in this way JWT module. register and this is the secret key and finally we have to refactor our OD service if everything is fine then we can use Au or JWT service you have to add this return type return type if password mashed generate adjacent web token or create a pad object I'm going to create a payload object now we are just adding email and the user ID inside the payload and it is generating the Json web token let's create a separate file for the constants can say o/c constants do let me refactor it here one more thing you got to register the JWT module in the Au module instead of app module that was a mistake so this is our authentication module we have to register it here out constants do Secret and you have to provide sign in options options we have expiry date which is one day so we have registered the jwd module now you have to create jwd strategy I can say JWT strategy dos it's nothing more it's a service or provider you can inject it injectable export class JWT strategy passport strategy it is going to provide the strategy passport JWT now we have to call Super Constructor and you can extract the header from Au header as a barrier token and we have to provide the ignore expiration check the expiry date secret which is our secret key ke and we will have the validate function whenever you apply at the O card this validate method will be called our next step is to register GWT strategy in the O module I have to register it here JWT strategy now you have to create the guard which is JWT guard dos export class JWT guard it is also a class or service provider that's why I I'm using the injectable and we have to extend it from the passport from the odard which is from the the njs passport package make sure you say this is the JWT if you want to extend this JWT guard you can do this our final step is to apply the O card to the public public route let's say I want to protect this route I did not create it yet let's say get profile and it is going to take request return request. user should be decorator now we have to let's do it without card npm Run start f our application is running now let's send the login request you will receive the access token I'm going to copy it and I going to paste it here access token now let's access the profile slash profile because we created the profile route in app controller I'm going to send the request cannot access the profile I do not add the route I can access the profile route I got the 200 status code it means route is working fine if I apply the authentication guard I can say use roles or use roles use guards yep I can mention my guard which is or guard if you have what in Express JS it's nothing more it's like a middleware this oard function will run before executing the get profile function this function runs before request Handler which is get profile oh it should be jwd o guard jwd guard not and this not this one o card let's rename it to JWT o guard not a JWT guard JWT oard it looks good let's try to access the profile route status 401 which means you did not provide the access token please provide the access token if you want to access this private route so you can provide the exess token by using this format I pasted the token awesome I got the user ID and the email I have applied the OD card and this JWT strategy method will be called first they are going to run the Constructor and then they are going to use the validate function in this lesson I'm going to teach you how to implement role-based authentication what is role-based authentication if your application has multiple roles like artist manager user accountant CFO person you can have a different functionalities for each role in Spotify clone when you look at the Spotify clone only artist can upload a song If you are a user like let me show you you with the help of Spotify web. Spotify like if I go to my profile I don't have any feature to upload a song Only approved artic can upload the song or delete the song in this way you can divide your application into multiple roles we have create songs endpoint I would like to restrict this endpoint for other users only artists should access this create song endpoint we don't have artist module we have to create artist module then we're going to implement the artist module into import the artist module into app module we have to write a method find artist on the B on user ID then we got to add a logic here inside the login method we will save the artist ID in the payload object and then you have to create a new payload type and finally you need JWT artist card we will have a separate card for artist we are extending the jw2 remember I told you if you want to customize or add a logic in the guard you can do that it's just returning a super Constructor and here we are using the handle request method this function will check if you have art artist if you are an artist then it is going to return the user otherwise it will throw the exception we have to refactor the validate method in GWT strategy we need an artist ID then here you will have to apply JWT artist guard on the create song endpoint you can do that as well or you can follow me let me implement it let's create the artist module here we have the artist module it has already imported into my app module this one the artist module we also need R service next generate service and I can say artist you have to import type orm artist entity module. for feature because I would like to use repository here artist repository we have to provide the Artist as an entity so we have the artist service and we also need artist controller artist I can use a nest generate controller artist now we have the artist controller now we're going to create the find artist method I'm going to copy my code inside the artist service let's do it here we need to import couple of dependencies we have to find the artist on the based on user ID our next step is to refactor the login method inside the art service we have to add R service injected we need to add a artist ID inside the payload type inside the payload if password matched find if user is an artist then we need to add the artist ID into the payload what I can say because course I can save the artist ID in the payload object user do p. artist ID should be it is saying that you don't have artist ID in the payload you can create a payload type inside the types p. type I can say types. yes now I can access it I can Define the P type it should be user ID we have mentioned the artist ID is an optional property now we need to have JWT oard I told you how can you implement it we already implemented the O card let's say I'm going to create a new guard inside the O I can say artist JWT godts export class artist JWT guard extends o guard JWT it's a Pur it's a service that's why I have to use the injectable it's a service provider if I will write the can activate you can see that I got the code all I need to call the super Constructor super do can activate and provide the context yep everything is fine you also have handle request now you can write your logic here if there is an error or there is a no user then you have to throw the unauthorized exception if everything is good to go you have to return the user if there is an artist ID then we should return the user get rid of the extra arguments I'm not using them when you apply the artist JWT card it should call the handle request and it will extract the user and try to check the artist ID from the user if you want to log the user you can also do that I will show you what will happen inside the user we created the JWT AR card JWT o card jwd arst card then we have to refactor a little bit validate method in the JWT strategy we can add the artist it should be P type now it looks good we have the user ID p. email and p. artist ID and finally we have to apply the jwd artist card on your protected endpoint in our case we have the songs create endpoint we have to protect it for other users all you need to apply JWT artist card and inside the songs controller I can restrict this endpoint from other users I can say that jwd artist JWT C if you want to log in the request you can do that let's try to do it here request decorator and request I think it should be request it's not a requ request this one request nexts commment and then we have to access the request why it's giving me the error I have to do it here and request now it looks good I can log request. user let's start the application I got the error the O JWT strategy JWT strategy what I did wrong oops forgot to add I forgot to add closing parenthesis if you go to the artist table you will not see any record because we don't have any artist record it's an empty if you go to the users how many users we have I have only single user now I would like to make the artist what I can say what is wrong is au module is a valid njs module Artist Artist service I think we have to import the artist module here inside the are we using the rst service yes we are using the RT service that is why I need to import the artist module and inside the artist module I can say I have to export artist service I want to teach you how to handle errors you must know you must familiar with error handling our application is running now first of all we have to create a new artist I can say let's sign up a new user or I can say that sign up artist let's say that it should be let's say c Martin Garrick Martin Garrick we have registered a user which which should be which could be an artist so if you want to make this user Martin Garrick to artist you have to update it manually but I did not create the endpoint but you can do that I taught you how to do it let's first of all the ID is to I'm going to open all the artist and we have to add the entry this is user number two and finally you have to save it now Martin is an artist so I have to log in as in Martin gar I can say sign up artist or login artist get rid of first name and the last name let's send the login request it should be login I got the token now if you check the profile it should have the artist ID you can see that this is the artist ID this is the user ID this is the artist ID from the artist table this one so it's working fine now when you have to create I for I got I I have to get the token again let's save the token the token will be deleted after one day I can say that arst token temporary if I try to create create a new song it should give me the unauthorized because you are not an artist and you did not provide the authorization token authorization b e a r a r e r now I can say we have artist which is one Mart Martin Garrick has an animal song let's say they want to publish this song I have the artist now it's working fine this is the user ID email and the artist ID user ID email and the artist ID so we got this one artist and the ID colon one we have successfully created the endpoint I can say request. user let's create a new song from Martin Garrick say love again so this is the request. user user ID email and the artist ID in this lesson I'm going to teach you how to use or how to enable how to create two Factor authentication you're going to learn how to implement two Factor authentication if you don't know about two Factor authentication you can read this text a user enters the username and password on a login page page after successful initi initial authentication the system sends you the onetime password or onetime token for the verification a user may provide the onetime code generated by the authenticator app and send to the system then system validate this token if token has validated then you are able to authenticate then you are able to access the route we're going to use third party package to implement two Factor authentication Speak Easy and we need a typing first of all I would like to show you the demo how two Factor authentication works I already implemented in my development project I can show you the demo first of all you got to log to the user I got the access token we're going to create a new endpoint to enable the authentication this endpoint will enable the authentication for the user and it will create a secret key let me show you I'm going to provide this text I provided the token now I got this secret key and I got this response from the Speak Easy package base 32 I saved this base 32 string to my database table for the user is for the user table a user has this record now I I I got this secret key if you have authenticator app Google Authenticator you can you can place the secret key I have enabled the Google Chrome extension I want you to do it when you look at Chrome Google Authenticator you have to enable this extension now I got this authenticator if you have Google Authenticator on your phone or you can install it all you need to do is to add a new app you can also generate the QR code with this OTP path Ot Ot paath OTP o URL you can generate QR Code by using this this URL but you can add manual entry for T testing Sam profile this is the same user the name of the user this is the secret key now I started getting a unique onetime password so I have to copy this password let me do it again it's going to be removed after 1 minute I copied it it's going to be removed yep now I have to provide this token to validate the user I have Pro I'm going to provide it here we also need to have updated token so copy this one and I have to validate the token yes we have to add a new token because it will be expired now you can see you are verified the token has validated now this user has enabled the two Factor authentication if you send the login request you see this message hey you have enabled two Factor authentication you can implement this Logic on your front end application please send the token at this URL please send the onetime password token from your Google Authenticator app on the front end side you can send request to this endpoint and provide the token that's a complete flow of two Factor Authentication let's start implementing two Factor authentication we have to install couple of packages we need a Speak Easy package we will use this package to generate secret key or validate the token onetime password we also need typing add it as a def dependency let's run npm install packages have installed the first step you have to add two new columns inside the user entity do entity I'm going to add them here by default two factor string should be null and it's a Boolean property by default I have set to default to false two Factor secret could be empty and this is the Boolean value when you run the application it should create two new columns for the user property for the user table our application is running now let's refresh the user table I have the 2 FAA secret and enable 2 FAA which is a Boolean column now we're going to create a new method inside the O service to enable the two Factor authentication first of all we need maybe we need a type I can add my type here enable to F type or you can create an interface we have to type and then we need a method you have to create a new method to find the user on the based on user ID if user has already enabled to factor authentication we have to return the secret key if user did not enable the 2 FAA authentication then we have to generate the secret key this is we use the secret key and we're going to use the base 32 secret key and finally we have to update the 2fa secret 2fa key for the specific user and then you have to write the do you have to return the secret key in the response we got to find the user if user already enabled the secret two Factor authentication we have to return the saved to to f secret otherwise we have to generate a new secret and then you have to set this secret for the user user and finally you have to update the user I'm going to copy the code let's do everything inside the OD service I have to create a new method import Speak Easy we also need to import Toof enable type we don't have a method find by ID do we have a method find by ID inside the user service not we have to create the find by ID method you can also do the secret key or unable to factor authentication here use user dot let me first add a new method inside the user service let's go to our next step user service here we need this method I'm going to copy this method now we have defin by ID it is going to accept the ID so we have to provide the user ID you can enable two Factor Authentication to true and finally you can call user. Save method or no we need a repository to save it we also need another method it will update the secret key and enable the authentication you can create a new method inside the user service let me import the update results we have completed the enable to factor authentication now it's time to test it let's create an O endpoint inside the O controller I I'm going to use the guard JWT o guard if you if you don't need anybody you can create it as a get end point I can say that JW the O card I just imported missing Imports we have a login user sign up user sign up artist login user here I can say enable two Factor authentication profile Au enable two Factor authentication let me double check that enable to fa we also need to provide the authorization token so we need to get get the token I got the the access token provide it here let's send the request I got the secret key that's amazing what is the name of the user which is John if you have Google Authenticator on your phone you can install it manually I'm going to add a new profiles which is John user add your secret key it is generating onetime password for 1 minute only we have also saved the key into the user users table let's fetch all the US users here we have the secret key and it has enabled two Factor authentication our next step is to validate the onetime password token let me open it we have created a new user or registered a new user in the Google authenticator it is generating onetime password we have to take this token or onetime password and try to validate with our application we're going to implement this logic first of all you may you may need another endpoint validate to fa we are also using a JWT o card we are getting the request here we will have a method validated to f a token it is going to provide the user ID the logged in user ID and we also need to get the token valid validate token dto we will create validate token dto I'm going to create a new endpoint inside the O controller I created the post because we need to get the token you can also use the get and get the token prams JWT oard let's create the validate token dto inside the dto I can have validate token. D.S now we have to create a new method to validate to fa token here we need to create this method it is going to accept the user ID the token the onetime password like this one this one this one and we will find the user on the based on ID and then we have to get this secret key which we saved earlier and then you have to provide the token and we have to mention encoding which is based 32 if token is verified where is that if token is verified then we have to return verified to True otherwise we have to return verified to false you can also rapar code inside the TR catch block I'm going to copy my complete code and I'm going to paste it here inside the OD service the code is complete self-explanatory now we have to test it we already created the route inside the rest client I can use that and I'm going to paste it here I can say validate to a token validate to fa let me double check my controller validate to fa it's a post end point point and we have to app content type application Json let's provide the token let me get the token John user amazing we got got the verifi to true if I provide the invalid token I got the verifi to false I got the verified false because because token has expired there is a new token we successfully enabled two Factor authentication validated with token you can add you can also add disabled authentication logic or you can have this feature let's implement it by creating a new function inside the OD service it's nothing more just disable the authentication and or set this value we need to have that function inside the user service because we have repository inside the user service I can say that so we have this method disabled to fa now it's time to create a new route to disable the authentication inside the O controller I'm going to create a new Endo here JWT o there is a typo here spelling issue for the O guard J WD o guard e everything is fixed now let's try to send disable authentication request inside the Au controller this is the get endpoint I can have that let me paste it here disable authentication disable to fa it should be disable not an enable so it has disabled authentication you can double check it by login I got the token and let me check it from my DB you can see that it has dis enable false set the false one more thing you can do if you disabled the authentication you can delete the secret key or you can use the existing secret key let me let me do it yeah we have to disable or deleted the key inside the disable validate token disabled I can say to FS secret to set to false or you can set the null value let's try to do the null value let's enable the authentication I got the secret double check it from the DB we have enabled and we have a different secret key I don't want to save the I don't want to change the secret key you should not change the secret key maybe it depends on your use case if client disabl this to fa maybe he has to scan the QR code again let's disable it it looks good we have empty to fa and it has set to false I also have to add this property into my notes if user has enabled to factor authentication we have to customize a little bit Logic for the login method we have to send the link to user this one validate to F token this one if user has enabled to fa and have the secret key then you have to return this type go to the login or service go to the login method here I can add a logic we have to add return type new return type this one let's try to access the login function by sending the login request we have enable two Factor authentication it should give you the link not an access token we have to log in the user where is the login user here we have let's double check it we have empty2 FAA that's why I got the access token let's enable it we enabled the two Factor authentication let's send the login now I got the link validate to fa please send the one onetime password or token from your Google Authenticator app you can implement this Logic on the front end on front end you can send the request to this URL and you have to provide the token a user user has to provide the token so we have completed the two Factor Authentication in this lesson you're going to learn how to implement API key authentication each user will have its own API Keys when he wants to access authenticated route or protected route he has to provide the API Keys when you need to control the number of calls made to your API you can check from your API Keys how many times API Keys has hit if you want to identify the usage patterns in your API traffic you can do with the help of API Keys API key authentication is typically used in scenarios where multiple users or application need to access an API you can read this text you can read the complete flow we're going to use this step we're going to generate API Keys we can create and store API key for each user we have to create an API key strategy strategy service just like we did for the JWT strategy and we have to register API key strategy in a module and the step number five validate the user by API key and apply API key authentication on protected route I have to use external package which is uu ID to generate API key and we will have API key column in the user entity and then when we have to create a new user what you have to do you got to set the API key which is U ID by calling this method it will generate a unique key when you send the when you create a new account it should give you this API key and Next Step you have to create API key strategy when you provide the API key it is going to call this method the validate function and inside the validate you have to call validate user by API key and you have to provide your API key if user is validated this is how you will provide the API key authorization barrier this is my API key we're going to use external package passport HTTP barrier to apply this strategy to validate API Keys finally you have to register as a provider API key strategy this is our method to validate the user on the based on API key if user validated with the help of API key this is our Endo here I'm I can say I want to access the profile on the based on API key or you can create in the O controller use guard o guard you have to provide the barrier it means I want to apply API key valid ation or API key authentication on this route and I don't want to set the send the user back password back in the response that's why I deleted the user password and you can send the message authenticated with API key this is the user this is how you will provide the API key when you make the authenticated request I want you to implement this complete flow if you stuck you can follow my video Let's install the package first let's run the application you will get the error because we have two to three records in users table but it will find null value for API key we did not set the constraint API key should be null if user has signed up we can have the API key or if if you set the null Lael to true you can have a separate function to create the API key for the user it depends on your use case your company or your business logic I'm expecting the null value error from the type orm we are using this database we have all the users you can see I got the eror relation user contains null value which is API key you can fix two or three ways you can set API key value manually but I don't have API key column there is a concept we didn't use the migration but I found the hack to use to resolve this issue I can say Spotify clone 2 let's change the database Run start there it will take some time to create all the tables database does not exist let's create a DB restart the application the application is running fine now we have this database Spotify clone 2 so we have the API key now we need to add the API key when you create a new account I can do it inside the user service or odd service do we have the sign up function here I think inside the users yes we have the create function I have to change a little bit logic I did not create a new user so I'm going to do it here we have to import this package we are getting the user. password delete this one we got it we got the API key yeah I can say saved password I have updated user D to user password and we have saved the password and we have deleted the saved password now we can we have to test it by sending this sign up request open the r client I'm going to send the request sign up request sign up user so it has generated the API key it looks good we have encrypted password it's fine now our next step is to create API key strategy we have to install this package I'm going to copy the same code and create a new file API key strategy inside the O API Das key Dash strategy. DS strategy. DS going to copy the code we are using the passport strategy and we are providing this passport HTTP barrier OD strategy we have to import or provide API key strategy inside the O module register it API key strategy and we have to validate the user on the based on API key I can create a new method I also need to find user on the based on API key let's add a new method inside the user service now it looks good let's create a new controller function into the O controller it means I'm telling to a or nests application I would like to validate this route on the based on API Key njs password everything is good to go right now we have to test the application run the application first of all we have to create a new account I change the email John 13 we got the API key I'm going to store the API key key John 13 now we have to provide this API key to access the profile route access profile we have a get end point get http or/ profile authorization basic here we have to provide the API key it's not a basic we are using this scheme barrier scheme b e a r e r now I got the user back in the response and it has authenticated with API key in this lesson I'm going to teach you how to debug nestjs application using VSS code if you don't have launch. Json file in vs code folder you can create it let's create the launch. jsn file if you go to the debug I'm going to create a new folder vs code and you can have launch. Json file let me copy these configurations so I have to start the application in debug mode nestjs has a script in package Chon file now you can start the application by running npm start Run start debug you can see that our debugger has started now I want you to attach a process when you go to the debug now you have to attach it you can put break points let me to here the O controller I'm going to put breakpoint let's try to send the API request it has stopped at this break point so I can see what is inside the request I have request body request client request. user you can also watch on a specific property the request. user you can see that I got the API key email enable to fa to fa secret this is a great way to debug the application you can find errors very easily by using debugging if you want to debug the complete flow you can do that into the app strategy what I was API API key strategy or API strategy yep we have the API key strategy I'm going to put break point here let me put the break point here and I would like to put the break point here let's send the request you you can see that it has first called this validate method it is going to find the user on the based on API key it has found the user now it is going to return execute this line return user it has now it has added the request. user you have returned API user from the API key strategy like this one nestjs has stored user inside the request object like request. user like this one and finally we have deleted it you can step over it go to the next line if you need to step into a specific function you have to use this one step in if you want to go out from this function you can press step out in this lesson I'm going to teach you the concept of migration migrations is like a Version Control for your database you can manage your database changes by using migrations migration is a file that contains a set of instructions for creating modifying or deleting database tables whenever you make changes in your entity you have to create a new migration if you want to go back to the previous changes there is a command for revert you can use that command once you get into the production right now we are building our application in development environment when we push the application into production you will set the synchronize to false so you have to manually update the changes to for your entities that's why I have set the synchronized to false in production you will not set the synchronized property to True migration is just a file with SQL queries to update database and apply new changes to an existing database I got the simple definition of migration it's called it's like a Version Control for your database you will keep keep track of your changes toward your schema first of all you have to move type orm configuration into a separate file these are all my type type orm configurations now you don't need to write your entities manually when you have to create a new entity you add a new entry for the entity now you don't need that I have added the regular expression for this path we also using the JavaScript because we're going to use migration I found it's easier to work with JavaScript when you are working with with migrations when you build the project nestjs will generate the disc folder this disc folder I can provide that path this is the JS file we're going to provide this type of file I have set this synchronized to false we have created a new data source when you write the script to migrate in package or Json file you have to provide the data source file this this data source and this data source has a data source object this data source object step number two you have to refactor type or M config into app module you got to provide data source options this dat data source options and then you have to write the script for type or M generate run and revert we're going to use all these scripts we will add a new column in the user entity and then we will run run the generate the migration based on this column this is the name of the migration at user phone where we have St about the migration here we have specified the path there is a DB folder and inside the DB we have migrations directory and finally you will run the migration when after creating the file you have to run the migration if you want you can implement this complete steps or you can follow me I'm going to create a new file inside the DB create a new folder inside the root directory DB data source. TS I'm going to paste this code my database is which is Spotify clone Spotify clone 2 so I have to delete everything here we have to provide a data source options this options object I have completed this step number two now we need to add couple of scripts there is no logic logic here specifically you can copy the scripts first of all please build the project generate the JavaScript files then and then we are using the type orm npx and dashd I'm telling to type orm I have stored my database configuration inside this file if if you have to go back or revert the changes you will run this command I'm going to copy this script and paste it here inside the scripts now let's try to add a new column user. entity I'm going to add a new column here here type A String now finally we have to run the migrations npm run migration generate I'm using this script here you are specifying I have I want to store migration in this file migrations and this is the name of the file it will also add the timestamp first it is going to build the project then it is going to execute this command meanwhile I have to start it from the scratch I don't want existing database so I would like to delete Del my database I'm also going to delete this one because we have set this synchronized to false we have to add changes manually that's why we are using migrations and new file has created inside the DB inside the migrations we have this file this is a Tim stamp and the name of the file add user phone. so we have to create a new database I can say Spotify clone now I want to add all this stuff like inside the data source Spotify clone let's generate the migrations I can say that my migrations you can choose any name or in it it is going to take all these entities and creating creating the SQL files SQL queries for all these entities because right now our database is empty in we don't have tables now you can see my migrations if you check the database you will not see any table because we did not run the migration yet now we going to run the migration npm run migration run now it is going to execute these queries these creating all the tables and all the relationships we have the migrations there is no record inside the migrations I'm going to delete this migrations and this migration file let's create it from scratch it has created all the migration now we have to run it everything is good right now it has executed the queries and now if I refresh my tables you will see all the tables we have songs users but if I go to the users I will have font property I don't want font property let's edit a user entity I'm going to remove phone now let's generate the migration I can say removed phone you can see that it has created the migration file removed phone it is going to drop this column now we need to run this migration to update changes in the database let's try to check the column there is no phone column here this is how the migrations work this lesson I'm going to teach you the concept of data seeding data seting is a process of populating a database with an initial set of data when you create a new column inside here when you create a new column in the user entity let's say I would like to add a new column and here I can say this is this could be the phone number but when you run the migrations the phone number will be empty in the database so you can load your initial data by running the seeds applying CED data to database refers to the process of inserting initial data into the database usually when the database is first created let me show you the demo of cing you are going to learn how to create the seed service and we have a seed method inside the seed service we are running type orm queries by using transaction here we have placed all my C data when my application bootstrap loads it will create a new user a fake user and it will save into the database and then it will create the artist and save artist into the user into the database we also have a c data for playlist first of all we're going to create a new user then we're going to create a new playlist and we have assigned a relation between playlist and the user so we're going to save couple of data when you run the application when application will be completed you can verify from your database let me show you in your users table you will see a new user will be created so these are all the users these are all the users I created with fake data by using the seaing I also have a playlist it is going to pick the random name for a playlist Rap playlist World playlist or country playlist I've also have a seed for artist you can see that now my application is is running now when you look at the users you will see another users couple of another users if you look at the playlist you will find one more playlist you can also look at the artist you will have more artist this is how you can increase your development workflow or testing workflow now I want you to implement it by looking at the documentation I created for you here I don't want a new column first of all we have to install another package to generate the fake data and next step we have to create a seeds folder inside the DB seeds I can data seed. TS file I have created a new file while here we're going to do initial seaing you can create a separate function for each entity like you can create a separate function for seed songs I did not create this seed songs method here you can create that if you want to look up more documentation of of Faker package you can find from your from the official documentation page it is giving me the error entities Source playlist here I can find the entity now our next step is to create a new seed module I'm going to use type orm to create a new seed module and then what we are doing here we are generating the encrypted password I use the same password for each user here we are creating the user I got uu ID from API key and I got repository from the manager we will call the seed data in main.ts file seed module has created we also need a seed service what I can do I'm going to copy this code and create a new service inside the seed module see do service if you want you can use CLI to generate service we also have to import or register as a provider seed service cannot find um oh it should be SE data seat should be I can say this seat data seat data and it should be gone we are making connection with our database here I got the manager from the quy manager and I called this C data and finally we are we have started the transaction if transaction if any query has failed it is going to roll back the transaction so our final step you can read this text if you want to learn more about what is cury Runner what is transaction here you have to boot you have to call the seed method here whenever you want to save a data in the database if you don't want to save a new fake data you can just disable these two lines but let me show you the demo I'm going to start the application it is going to run these methods seed user it is going to create a new fake user seed artist and Seed playlist let me show you the current look of my schema I'm using spotify clone on database Let me refresh my tables uh I would like to see all the users there is nothing here I don't have any user you can create many users if you want you can use fake package to generate 20 15 50 55 records and you can and then you can provide into the repository user repository it will create all these records but I use a single record I just want to show you the process you can manipulate with your own use case one more thing I could not find the official package or official documentation or in typ orm seeding I got I have implemented my own strategy now my application is running you can see I have couple of new users you can see I have couple of new artist I think I will have only single artist yes but if you look at the users it has picked a random first name random random last name random last name and the email and the password and the API key it has generated one more thing if you want to look at the playlist I will also have a one playlist electronic music song that's how the seeding work works whenever you create a new entity I would recommend you to create a seed function whenever you run the application it is it is going to create a new data but I'm going to comment this code you can enable the seaing here if you want to make it more Super productive you can create a console command in njs I'll teach you in the advanced Concept in this lesson I'm going to teach you the concept of configurations we're going to create custom configur ation file with the help of nestjs config if you see our main. file I have mentioned the port number manually if you want to have a separate port for development project or for production environment you can specify in the environment variable we don't have any EnV file in if you have worked with nodejs you will have separate EnV environment file. EnV file for development and you you will have separate. EnV file for production one more thing if you look at our type orm configurations here we have type orm configurations I have specified a username manually password manually database manually I also specify the host manually what if you want a different environment variables for production let's say you want to deply the project to AWS or Hoku you need a separate en andv environment variables for production level but we did not Implement that logic now we need to do it if want to read what is configuration you can read this complete text I have explained configurations you may need a database setting for in for development and production you may have different API keys for production and API keys for development you can have multiple environment files for production production and testing nestjs provide provide config module we're going to use this package I'm going to copy it and I'm going to paste in my dependency section or if you want to install manually you can do that I have to do npm install in The Next Step you have to import config module in the app module this config module will have config service and we're going to use the config service to access the environment variables let me show you how can we do it package has installed now we need to import config module into the app module geted of these extra dependencies we have to import it here let's import config module so here we have config module after importing config module you have to provide the path of your EnV file here you have to provide the path we don't have any EnV file go to your root directory and create two files the first one for env. development for production level I can say en EnV for production this one is for development and this one is for production if you want to have a separate port for different environment you can do that but I'm going to keep with 3,000 for production you can place it here so we have created the EnV file so how can you load this EnV file we have to set the path in the app module here I have to provide the options configurations I can say EnV file path it can access the array the first one is do env. development and do EnV do production one more thing I would like to mention we have used the config module inside the config module config module is using do EnV package if you Google the envv this package is used to define environment variables for different environments for development and per for production but by default nestjs config package is using the EnV we have used this load ENB property so what you have to make it Global let's say I would like to import EnV module into my Au module into the artist module let's say I want to use API keys from env. development file to artist module you don't need to import config module you can use config service automatically but if you use if you make a global when you want to use config module in other modules you will need to import it as it standard with any Nest module or you can make it Global I have set it to Global so I can use config service without importing the config module now we have to create the custom configuration file you have to create a new folder inside the source folder I can say config let's create the configurations here you have to place all your configuration you have to define configuration inside the EnV file and this configuration dots file is is going to fetch or add validations for environment variables inside the configuration so config module is going to use this configuration .s file it is going to to extract all these values from config does let me show you how we have to load our configuration file custom configuration file I can say load you can have multiple configuration file you can have different configuration file for database you can have different configuration file for app settings or user profile settings something like that but I'm going to keep it simple let's use a simple configuration file we have to import the configuration now our next step is to test the EnV variable we have created the port and we have defined or getting the port from uhv and here now let's say if you want to access this port variable I'm going to do it for testing purpose don't do it in production inside the O service let's say I can define a new Vari new function get EnV variable you can call any function here here how can you use the configuration dots file while how can you get the this port into your a service like we have to inject the config service we have to inject the con config service config service remember I did not import the config module into the Au module because we have set it to Global in the app module so we can use config service config service. get pass it into as a integer you have to provide the name of your key which is Port when you open the configuration. ES file we have specified the key which is Port so how can you use this function let's say I'm going to create a controller function for testing don't do it in production I just want to show you the demo I can say test get EnV or you can say test EnV variable it is going to return this do out service calling the get EnV variable that's it do not do any fancy stuff here let's start the application and we have to test this route now we need to test it I have to send the request to this URL this endpoint we have to send the get request can say test EnV 3000 sl/ test amazing I got the Port Port value which is 3,000 it's working fine now now if you check the main.ts file we have defined the port into configuration we are using the port value manually I would like to use the config service here I want to get the Value Port value from the config service and I would like to use it here this is how you can do it you can get the config service instance from the by calling the app.get method and providing the instance providing the config service class it is going to give me the instance config service then I can use the method here so you can do it here config service you can import it now I can get the port value service. getet let's pass it as a number here I can say the port which is key get rid off this no I'm not using seed service we have our application is running fine now let's send the test test request test I got the port 3000 we successfully configured the port in the main.ts file now we also need to add our secret key inside the EnV file we are using getting the value from the Au constants but I don't want to get it from the Au constants I would like to add secret key inside my EnV file I have to place it here secret now I would like to use this secret we are using this secret inser the app module inser the Au module not app module here we are using the O constant. secret but I want to get it from the config service I want you to think about it how can you add or how can you get the value from config service we also need to add a property in the configuration I'm going to do it here and this is how you will get the value from config service we have to register this module as a async and and it is going to return the dynamic module so you have to follow this pattern if you want to configure Dynamic module Dynamic module is a feature that allows you to dynamically configure and register modules at runtime based on Dynamic conditions so we have this Dynamic value so what I want you also have to inject the config service you have to import the config module this use Factory is used to inject the config service and we are getting the value here so I'm going to copy that I'm going to replace my Au module with this code import config service and config module Imports I don't want to use the O constant get rid of the Hat we have to import config module we also need to import config service that is it now we have specified The Secret inside the configuration did I Define the secret in the production I think I did not if you want you can do it env. production let's restart the server our application is running successfully it means we successfully configured the secret key you can test it by sending the API request I have to open it here rest client I can send this signup request it's oh I got I sent the login request we have to send the signup request user has created successfully it's working fine now now our next step is to configure the DB configurations database configuration I'm going to add the configurations inside the my EnV file development file if you want to add a separate EnV file separate configuration for database you can do it can say that DB configuration my database is end test now we have to define the values inside the configuration. ES file I'm going to copy the same code or I need these values now we have to update or refactor the manual values with configuration config service so I I'm going to create a new type orm async config object and then we're going to use inside our type orm module let's refactor it you have to create it this is the same process you have to create this module or register this module as a dynamic I'm going to use the same configuration when defining the type or a module I'm going to do it here you can import type orm config options we also need to get config module and config service type or module options I got the DB host DB Port username DB name password entities and synchronize set to false here we are going to get it from the process.env I'm going to copy that code and I'm going to paste or you can say replace this text host inside the app module we have to register it type orm module this time type orm ASN config get rid of data source wrong driver I think something is missing postgress we have to use the for root async in the app module I think that is why it is showing me the error you can see that application is running fine now it means we have successfully configured the database we have successfully configured the settings it's working fine now in the previous video we have created the environment variables we have set up the DB configuration DB Port username password and database name we if you want to add the validation if you want to validate these environment variables you can also do that with the help of class validator package to implement the validation you have to create the env. env. validation. TS file we did not add node EnV inside the development or production. EnV I have set the Isam which is enum here I have defined the validation for Port DB host username password DB name and the secret we're going to use class based validator class validator package that's why I created the class and we will have the validate method it is going to accept the config object with record key value pair first of all we're going to use plane to instance from class Transformer package plain instance converts a plain literal object to class based Constructor object you can learn more about class Transformer by looking at the doc so class Transformer allows you to transform plain object to some instance of a class you can look at the documentation of class Transformer if you want to learn more about it and you have to enable this property to true and we have to provide the environment variable which we have created the class this one environment variables and we have the config SE config object you I'll teach you I'll show you what is inside the validated config now it should be the instance of a class if error comes you can send the error back otherwise you have to return the validated config and then you have to provide this validate method inside the config module we don't have node EnV you can create inside the environment variable let me do that first env. environment I'm going to copy that in the production I'm going to copy here now you have to create a new file inside the root directory env. validation. TS file file we will have the enum for development environment it could be development production test and provision now you have to create a class to validate the environment variables we have Port dbhost username password and the secret now we have to implement the logic for validate function it should return the validated object validated config so I got the instance of the class we provided the environment variables here let's say if I would like to log the config I can say please log the config and here I would like to say please log validated config now we have to perform the validation there is a validate sync method you can use it let me import them I'm going to import them here if error comes we need to throw the error otherwise we need to return the validated object validated config object so we created the validate function now it's time to register it inside the app module I'm going to register it in the config module here there is a validate we have to import the validate you have to import it manually it's not giving me the suggestions can say validate from it should not be EnV it should be env. validation that's why I'm not getting the suggestion because this is a typescript file it's not an environment file now I should get the suggestion for validate let me import it from env. validation do not import it from the class validator package I would like to test this application you can see that we have I have the config object inside the the config object I have the property Port secret node EnV DB host we Define these properties inside the environment file. env. development I got the DB name all these couple of things now you have environment variable which is the instance of a Class A Class based object in environment variables I got all this port all this stuff I'm going to comment this out what if I set the wrong value in the development file let's let me test it if I set the DB Port should be string let's say that it should give me the error I have to restart the application because I have made changes in theb do development file I did not set the validation for DB Port that's why I did not get the error let's say I'm going to do it here DB Port I can say the type should be number I have saved the application I have to restart it you can see that I got the error property DB Port has filed the following constraints is number let's replace the DB Port we have successfully implemented the validations for environment variables in this lesson I'm going to teach you how to increase the speed of module reloading what do I mean by module hot reloading if I change anything here in any file it will take too much time time to reload the application if I'm going to log something here now my application is running first time it will take some time let me show you the problem and what problem we're going to solve and how we going to solve that problem e for in this lesson I'm going to teach you how to increase the speed of nestjs project reloading if I make changes in any file let's say I'm going to delete this code it will take some time to reload the application I would like to increase this speed with the help of web pack you can see that it's taking too much time to reload application nestjs provides a way to increase the speed of your hot reloading you can see that it's still calculating the changes it's still calculating waiting for the file changes I think it has took 30 seconds to load the application let's increase the speed with the help of weback first of all you have to create a new file web H hot modu reloading doc config you have to create this file inside the root directory and I'm going to copy this code because I'm not not going to teach you weac in this course and step number two we have to make some changes in bootstrap function I can open the bootstrap function in the main. file we have to add the code here if module. H then you going to do this process it is asking me which module I going to talk about let me check it from my project yes I need to declare module as a variable I can I would like to declare it here I can also add that part into my documentation now our third step is to add a script to use web pack instead of default configuration to run the project in development mode we have to refactor the start dep script I would like to change it and let's do it this time we're going to run the project with web pack e cannot find run script weback plug-in do we need to install it oh yeah we need to install it e make sure you installed it as a Dev dependency so I need to uninstall it now we need to install it as a dep dependency let's run the project weback is building your sources project is completed let's try to send the API request but it's still running first time it will take some time to initiate the project now project has completed it's time to send the API request I'm going to send API request to root URL let's say I would like to make some changes I can say hello world I saved the application now you can see that it took 2 to 3 seconds to reload the application updated modules you can see that it also loged the message updated modules so I'm going to move this line application has started again I found it's very helpful when you are building a project in development environment we're going to use Swagger package to document the apis if you don't know about Swagger it's an OP Source software Frameworks that enables developer to document and design the restful web services it provides a set of tools and specification for defining the structure end points and data models of an API we will have Swagger specification Swagger editor and Swagger UI if you haven't looked at the Swagger let me show you the demo this is the example of swagger documentation you will have all the end points what these end points are doing you can look at as you can see that we have profile route we have all these routes available you can also create a section for each each route I'll teach you how to do that so I just want to show you this is the overall view of swagger documentation so we have to implement it first of all you have to install a third party package which is nestjs Swagger uh Swagger Nest has created this package let's install this package or I can add into my package.json file let's install it Swagger package has installed now we need to configure this Swagger module in bootstrap function you have to do it here you can use document Builder from a Swagger module you can have to set the title title should be Spotify GL the name of your application and you can write the description for your application you can set the version and finally you got to call the build function and then we will create the document with the help of swagger module and you have to provide your application instance and this config module this config setting and here we're going to mount the Swagger document at/ API route and you have to provide the application instance and your document I'm going to copy the same code and I'm going to place it here inside the bootstrap function you got to do it here let's import Swagger module I'm not getting the hints for Swagger module and document let's import manually cannot find a module nestjs worker why I think I have to install it manually and install next just swager now the error is going now we have a Swagger dependency here we have the nest F package you can write the name of your title application and you have to write the description version and finally we got a call the build and we are creating the document and we have set up the Swagger module it's time to run the application oh there is an issue it was an extra parenthesis application is running now let's try to test it I can go to the Local Host colon 3000 SL API now we have the title of the document and the description we have all these routes but we did not add the tags I'll show you tags in the next video let's try to send the request to the root URL so I got this response hello I am learning nests fundamentals if I execute this endpoint I got the port the 200 status code in this lesson I'm going to teach you how to document this signup route if you look at this signup route I don't have any schema yet it's not displaying the schema what type of parameters do we need do we need first name do we need last name I also want to show the description or the purpose of this signup route first of all you have to add the API tag to the O controller let's convert all these routes into o section we're going to place the login route into OD section enable to fa and validate to fa let's do it first I'm going to open the O controller here I can say API tags I can use the Au my application is running now you can see all the routes are placed inside the O section one more thing I would like to add in the O controller we have to decorate the sign up route the next step we have to add the API operation and the response I'm going to use the API operation we need to get it from this Swagger module it will return the user in the response with 2011 status code this is called please register a new user make sure it's running now let's refresh I cannot see the sign up rout I think it is taking too much time oh I found the error API response we need to get the API response yes we have the API response let's restart the application now you can see that we have the register user we have specified it here somebody which is registered new user and you can see the response it should it will return a user in the response let's try to test it if I if I provide first name NH last name shsf and we have to provide email SN gmail.com let's provide the password 1 2 3 4 5 let's try to test it out internal server error because let me look at the error entity metadata note found no metadata for a user was found I found there is an issue with type orm and a web pack if you use vbac hot reloading like we have used weac package to reload the application fast type orm does not work with this configuration like this one we have to replace it and you have to register all the entities manually but it can work with migrations there is no problem with migrations but you have to replace it here we have to import couple of entities application is broke now I think I have to restart it application is running fine let's test it out I'm going to create a new user a user has created successfully you can see that with 2011 status code when you look at the sign up route if you check schema it is not displaying me in the schema what do I mean by schema here I cannot see the login dto I don't have create song dto I don't have create user dto it should display me the schema let me run the application my application is running now if you look at the schema in the signup route you will see the empty create user dto you can fix it with the help of API property you have to tell Swagger hey this is the API property I want to I want to see in this Swagger document let's add API property in the user entity we have to do it here please provide the first name of the user first name of the user let me import API property you have to do the same thing for last name you can also add example like what could be the data type look like I'm also going to add API property for email let's do it for the password my application is running now but I cannot see this schema value I cannot see properties here for my schema you have to register nestjs Swagger plugin you can do it in the nest CLI I'm going to copy the plugins open nli and I'm going to do it here let's restart the application because we have modified nli let's refresh the application I cannot see my schema I have to register the plug-in inside the compiler options that was the mistake restart the application now you can see the schema value first name last name email and the password it will also show you the schema value for login dto here we have the user example value email ID API key playlist in this lesson I'm going to teach you how to test Authentication in Swagger document we have to enable barer o it's a scheme you can do it in main.ts file you have to add this function Nest Swagger module provides this function add barrier o this is the type HTTP scheme is barrier format should be JWT name is JWT you can add you can add the description jwd token and I would like to provide in the header this is the name when you need to use or apply on the controller function one more thing we also need to update the secret key in the JWT strategy I don't want to use o constant. secret I I have to get it from the process.env secret this get profile is our protected route if you want to apply authentication or app if you want to protect or apply authentication of swagger document you have to use the API barrier a and this is the name we use jw/ here this one like create songs endpoint is also a protected route you can also apply authentication on that in the songs controller these are all the protected routes only artist can access update endpoint delete endpoint and create endpoint so you can apply Authentication on these routes as well but I just want to show you the demo in the app controller we have this protected route get profile endpoint let me show you in our Swagger document SL API here we have login route we don't have any authentication section let's implement it first of all let me write documentation for login route inside the O controller it looks good now we have to enable the authentication I'm going to copy the code and paste it here now we have to apply JWT authentication we also need to update the secret key in the JWT strategy I don't want to use o secret from the O constants let's get it from the environment variable and this is we have to use I'm telling to Swagger hey Swagger this is the protected route application is broken now restart the application I found an issue when you are working with we hod module reloading do not save the application if your application is in error format if there is an error in the file do not save the application otherwise it will break the V hod module reloading now it it will take some time to restart the app application application is running now I have to refresh my page now you can see the authorize if I try to access the profile route from here it should give me the error unauth red so you can you have to log in to get the access token I'm going to send the login request password does not match what was the password 1 2 3 4 5 6 I have got the access token now I can use this token and I'm going to provide it here this is the name JWT o you can see that authorize Now by enabling this JWT o here this Swagger will use this token just like we saved here let's access the protected route you can see that I got the user ID and the email it has already attached authorization barrier and the token if you have all protected routes in the controller you can also add API barrier or here for all controller routes but I have only single route is protected protected this is the public right route that is why I did not use the API or o barrier or inside root inside the controller for a controller so I applied separately API or API barrier OD you can also Define the tags for songs controller I want you to do it you can apply High authentication on songs controller protected route like create is a protected route you have to add API or o barrier decorator here it did not create the aay tax because my application has broken now by using this code restart the application my application is running now I can see all the songs related route you can also do it for the playlist API TX you can see the playlist section in this lesson I'm going to teach you how to install mango DB using docket compose if you don't have installed mongod DB on your machine you can install it manually or you can install with Docker compose I have already installed Docker on my machine my Docker is running you can see that here is my Docker is running now but we don't have any project right now to use with mongodb I don't want to install mongodb in my previous project we're going to create a new project to play around with mongod DP database I want you to create a new project I can say Nest new and we need to provide the name of your project I can say n production nestjs project with mongod DB and I want to ship it on production level you have to choose your package manager I'm going to use npm it will take some time to install the dependencies my project has created successfully all the dependencies have installed I'm going to go to my project I'm going to open the project into my vs code let me run the project by using npm Run start Dev let's commit in it and I would like to create a new Branch I'll store this code into this branch to connect with mongodb we will install this dependency or this package in the next video or you can install it here we need NCS mango package and we need mango separate package this is the magic we need to implement we're going to use docket compose to start mang DB driver I'm going to create a new file in the root directory I can say Docker compose EML you have to Define your version I can say one you have to define the services here we need to define the service mongod DB or mango mongodb the name of the service you have to provide the environment I can say mongod DP database and we need to provide the name of the database which is test we also need to provide the image we need to get the local uh latest image from the docker repository Docker Hub or you can say let's define the port I'm going to copy the same code I don't want to make mistake that's it or you can change your database I can say Spotify clone now you have to start MB driver you have to execute this command do compose up my project I'm going to open my project into R directory and let's execute this command I think already allocated I think my already project is running on 2701 docket compos let me stop that project project here we need to stop it let's try it again now it is going to start the mongod DB I'm also going to use external tool it's a graphical user interface mango DP Compass you can install it you can play around with GUI with mongodb database this is the GUI mongodb mongodb Compass you have to have a new connection you can have a new connection it is going to ask me the host and the port I can say Local Host and this is the port 2701 because my mango DB is running on this port 27017 so I'm going to connect it and you can create a new database Spotify clone and you can have the collection which is songs you can see that I have interacted with mongodb database and I created a new database so our mongod DP driver is running successfully in the next video I'll teach you how to connect nestjs application with mangos or mongod DP in the previous video we have installed these two packages mangos and nestjs mangos if you would like to connect nestjs application with mango or mango DB you have to create a new module in the app module you have to create it by calling the for root method this for root method is similar to mango. connect from the mango package you can read the connect package from the official documentation what I want you to make sure your mongodb is running my mango mongod DB driver mongod DB is running with the help of Docker I use Docker compose up here it is running Docker compose up now we have to call this method mongos module. forward in the app module make sure you have this database Spotify clone if I run the application let's see what will happen npm runs start def mango module because we did not import it let's import it with the help of VSS code I'm going to save the application you can see that Mango's package has installed it has also initialize the mango score module dependencies it means we have successfully connected to mongod DP if I will write the invalid Port let's see what will happen I'm getting the error mangos module unable to connect the database so it means we have configured the mango DB with nestjs but if you look at mango Compass I think I don't have Spotify clone database it can work without creating the database if I create the database it will work I can create the name of the collection now we have Spotify clone it looks good now we're going to create schema using mongos model in mongos everything starts with schema each schema maps to mongodb collection and different finds the shape of the document within the collection schemas are used to define the models and models are responsible for creating and reading documents from the mongodb database so we're going to create the first schema you have to create a new folder songs here you have to create the schemas folder and you have to have a schema which is songs. TS file but we will use this song document when we will inject the model into song service you can use the decorator schema nestjs mango module provides schema decorator this prop represents the property in the collection we will have songs collection and inside the song collection we will have these Fields Title release date duration and the lyrics Yep this schema decorator marks a class as a schema definition it Maps Our Song class to mongod DP collection of the same name but it will add S at the end of the final mango collection name will be songs and prop decorator defines a property in the document and finally we will have schema Factory it will return the raw definition of schema I logged on song schema and I got this result schema object we have these properties title release date and duration and couple of metadata for each field this is how you will create a schema I want you to implement it so I'm going to implement here by creating a new folder inside these songs we will have schemas here I'm going to create a song schema or song. TS file I just pasted my code we have defined four Fields I got all these properties from our previous project which we worked with tym and post I got title release date duration and lyrics I set this data type for dur string I couldn't find a Time Field Time data type in mangos so you can validate manually duration by using third party date plug-in so we created the schema successfully this lesson I'm going to teach you how to save record in mongodb database we're going to save record card in mongod DP collection right now we don't have a songs module we don't have songs controller we don't have song surveys we're going to create all these stuff and then we're going to create post end point inside the songs controller you have learned how to create the post endpoint how to create network request object or data transfer object dto and then I'm going to use song song service song service has create method to save the record in mongodb collection and finally we will create create song dto object inside the create song d. file and here I would like to inject the model remember schema will act as a model you can use schema to generate a model so I'm telling please give me the model the name of the model which is songs and I would like to use here I would like to inject it as a dependency I remember I have created the type in the song schema file I got the song document and this song model provides crud operation create read update and delete it is similar to type orm repository it will be treat treated as a type RM Repository and finally we have a safe method in the song model and I am going to call the method here it is going to return the promise and finally we have created the songs module we have to inject the song model just like we did with type orm repository if you will not do that part you will not be able to inject song module here that's why you have to register it as a here I'm telling to njs I would like to use song model in the service or in my provider and then you can send the request to this URL to to create a new song in the mongod TB collection I want you to implement it let me implement it for you let's generate let's generate controller songs let generate so service songs it has created the songs module it has also updated the entry in the app module you can also see the songs controller it has also updated Creed the songs controller inside the app module you can see that now we have songs module inside the songs module we have songs controller and the song service now it's time to create a new endpoint I'm going to copy the code inside the songs controller we just injected the song service right now this create method does not exist in the song service we also don't have create song dto Let's create let's create create song dto I'm going to create a new folder dtos and I'm going to create a new file file create song hd.s file that's it I already taught you how to create a method in the service let's refactor the song service add a new method we have injected the song model make sure you provide the name of the song model here we are injecting the song model and I called called create method from song model and finally we have to tell njs I want to use this song model in the songs module so please make it injectable and now we have to run the application I have to import song dependency song it looks good we have to test it I'm going to create a new file to make API request I can say api. HTTP let's send the API request you can see that a song has created we can verify from Compass here is the record inside the songs collection let's add another song so we have another song it should display the second song but I cannot find out no I can see the second song we have two records in mongodb collection this is the document if I don't set the title what will happen you will see internal server error because we have set the validations inside the song schema these properties are required title is required release date is required and duration is required in this lesson you're going to learn how to implement find and delete method we will create two endpoints to handle find and delete request let's start implement it I have already taught you how to implement crud or rest based API end points let's create a method find to fetch all the records from mango DP collection it is going to give me all the documents now we have to create a route to handle the request our application is running now let's send the API request to fetch all the songs we have to send the get API request we don't have any record yet let's create a new song I have I've created a new song I'm going to create another song now we have two songs let's fetch all these songs we have successfully implemented the find all method now it's time to implement the find by ID I'm going to create a new method find by ID in the song service and there is a method find by ID in the song model you have to provide the ID we're going to get the ID from the request parameter let's create a new route now we are going to send the request to fetch song Only based on ID find one song we have to get the ID I'm going to send the request to fetch all the songs now I'm going to copy the ID and we need to provide the ID here so I got the single record on the based on ID you can also implement the delete endpoint I'm going to create a delete function inside the song service song model provides delete one method and you have to provide the ID mango work works with underscore ID if you have worked with mongodb the ID stored ID stores in this underscore ID format if you if you are using or have used postgress or MySQL in my SQL or postgress you say the primary key or primary ID with this ID without underscore now we have to create a delete endpoint in the songs controller we have to get the delete method that is it let's create a new song because we're going to delete that song I'm going to get the ID and now we have to delete the song to send the delete API request delete song you can see deleted count is one acknowledged true it means we have successfully deleted the song you can double check it by sending the API request to fetch all the songs and you can see new song does not exist here you can also implement the update functionality I already taught you when you were learning type or mcard operations similarly you can implement the update operation you can have you first of all you have you have to Define update function Here song model provide the update method you can use that method and then you got to create a controller to handle the update request in this lesson I'm going to teach you the concept of populate if you want to make a relation or a reference between two document between two collections remember in mongodb collection collection will have documents in my SQL or post you will have tables and columns so if you want to make the reference or relation between two collection you can do with the help of poate you have to implement the concept of poate I have this use case or scenario each song must have must belong to one album and each each album can have many songs I want you to implement it if you want to do that you can Google Mongo's relation or check the official documentation this is our album schema we did not create the album schema yet I'm going to teach you how to do that or you going to create or you can create the album schema just like we did the song schema scha it is going to take the array of the songs because each album can have many songs that's why I created the array of songs and you can have multiple types it's an array I got the types from mango package here you will see type from the mangos and I'm telling that the reference is songs because when you create the song when you created the song schema you have defined a class for class song by default the collection will be songs you can also double check it from mongod DB Compass let me show you I'm telling you I would like to make a reference with songs collection let me do that inside the Spotify clone we have the collection name which is songs I have added the reference here and finally you also have to add a relation for this for the album in the song schema I'm creating a property and type should be Mango's object ID or mongodb object ID here I'm I'm getting the or defining the reference album. name it should be albums and we have the album and finally you got to create album module just like we did the song module and I'm saying I want to use the album model in the album service or we we will be able to inject the album model to perform crud operations and here I have injected the album model in the album service just like we did songs model inside the song service and I created a new method we will have a create album dto and here we will have find albums this is how you will implement the populate let's say you want to display all the songs on the front end against each album then you need this query you got to I'm telling to mongod DB please give me all the albums please give me all the albums for each Album please also give me all the songs this is how you going to do it and create when you are trying to create a new album you got to provide the title and the songs it should be the IDS and we have create method to create a new album and uh find all albums and you also have to refactor create Song D you can implement it I want you to do it I already taught you all of these steps to do that first of all we have to create album nextest generate nextest generate module albums or I can say albums and next gener at controller album and Nest generate service albums Nest generate module albums Nest generate controller albums Nest generate service albums I don't need spec files I'm going to delete them now you have albums module albums controller and album service it has also added the entry in the app module let's create a new folder schemas I have to create create a new schema I can name it to album schema. we will also need a dtos now we're going to I'm going to copy album schema and I'm going to paste it here that's it and I can use I also have to refactor the song schema we have to add another property one thing I forgot to add it should be a mongodb property that's I forgot to add add prop decorator for the lyrics property we need to get the types from object ID from mango we also have to import the album from album schema everything is good right now let's create we have to update album module actually we need we need this line I'm going to copy everything e we don't have dto let's create that create Alum dto now we have to define a controller we already created the controller I can say should be albums controller album service and we also need to refactor the create song dto I have found the error in the album service get rid of the song Let's import it here if I save the application we also have to refactor in the song schema everything is good now what we what I want to do I would like to create the album first create album we have to send the post request by providing the data it is going to get give it is going to asking me the name of the album title title of the album let's say dance and I would like to provide the array of the songs I want to save let's say these two collections these two collections inside the dance inside the dance album I'm also going to save this document or save the song inside this album let's create a new album I got the eror song validation failed duration duration is required OMG I forgot to add the albums here now you can see that I got the dance album with these two songs now we have to fetch all the songs I'm going to test the popular method popular functionality find all albums with songs this time we have to send the get request let's fetch all the albums you can see that I got the albums array this is the first album and we have all the songs against each album this is how you can make a relation or reference with document with collections or with models in this lesson we're going to prepare our application for deployment I'm going to teach you how to deploy nestjs application at Railway you will also deploy your postgress database at Railway we're going to deploy our application this one the Spotify clone which we were building our application is using postp database with type orm I'm going to teach you how to deploy the complete application at sailway first of all you got to create a new project make sure you deploy your project at GitHub repository I did not deploy the project yet first of all we have to do a do a little bit configuration we have to set our environment variable when I will run the application in production it should run this production. EnV file if I'll be working at development environment I want to work with local post database I don't want to change in production level so we got to configure a couple of settings we already created the env. development. env. production but it is not configur configurable when my project is running in production mode it should pick this production file I've already written down the validation in EnV validation for node environment but I did not set in the configuration let me do it I can say node EnV and I can get the value from process dot process. env. node EnV now this variable is available for the config service I've already provided you the nests deployment raway started kit BR started kit project you have to open it and run npm install to install all the dependencies now we have to configure the EnV file path in app module get rid of this stuff I don't want to do it configure get it off this middleware get rid of this data source here we have to update our path what I can say please get the value from process do do EnV do node EnV or you can say get the path from the current working directory and you can provide the name of your file current working directory and Slash dot here we need to do EnV dot development or production we have to remove this one please get the working directory and find the env. production file or env. development file we have to set the script or we have to set the development environment in our package.json file for the dev I can say I want to mention node EnV to development we have to do it here we have to set the production value when you run the application with production how can I test it in the main.ts file maybe I can use that or what can I do yeah I have the access to config service I can say console DOT log config service doget I can provide the name which is not EnV let me part it to string let's see what will happen you can see that it's working fine now my application is running in the development environment if I run the application in produ prodction environment when you see the production. environment I don't set the I didn't set the database configuration so it will not work my application will be crashed let me show you you can see that my application has crashed an instance of environment variable has failed yeah it is showing me the validation error dbport does not exist DB host does not exist if I copy this configuration what will happen now it should run the application you can see that my application is working fine now but we will replace these configurations with Railway post configuration I have everything in the master Branch let's create the GitHub repository because Railway will be asking for GitHub repository let's create a new repository I can give any name nextjs deploy to railway if you want you can create private repository I'm going to make it public we have to add origin it is asking me to create push as a main branch let's do that so I got the main branch everything inside the main branch let's try to check it out so I have everything in the main branch now we have we have EnV doev development we have env. production you should not push your env. development or env. production to the GitHub repository because we wanted to set it to the kit ignore do not add Dov files if I add. EnV update get ignore we have to push the code I try to add do EnV in the G ignore edit I try to add EnV in the ignore and it was not not working I also removed the cache for env. development and env. production file removed envs now we have to push it oops envs let's push the code let me delete this file manually I'm also going to delete env. production now we got to pull the code everything is up to date right now if I try to push you should not see env. production and EnV do development file so we have pushed the source code to our GitHub repository you going to say deply from the GitHub repository here we have to configure our repository I can say deploy njs app to I can say now it is going to deploy the code it is building and running env. production no it is trying to building the project now you can see that our project has deployed if you want you can see the log what is going on here I got this error instance of environment variables has failed in the valid validation that's an issue we have to configure our environment variables our application has crashed now we have to set the environment variables first of all I have to create a new database it's very easy to create a database in real way just right click and find the database I'm going to have post now you can have the post when you see the connect here you can find your database option I can say this is post and you can up create your EnV production file EnV production oops I deleted that files we need to get back our development. EnV file do env. development and I also need to get production EnV file now I'm going to copy my database in the production let's do it here database this one and we need PG Host this one and we need password I want you to use your own password do not copy my password username it should be post it's working fine you also need a port everything is good to go now now I want you to copy these EnV file the your production EnV file and open the N nestjs deploy to raway project and in the in in the variables you have to set your environment variables that's it I'm going to update my variables now it is going to redeploy the app application now redeployment is in progress It's Time to it's it will take some time my application has deplo deployed now it is going to start let's look at the deployment logs amazing I I was logging the production in the app module or I think I was doing in the main.ts file you should not do that it's working fine it means we successfully deployed our application so how can you test it maybe you had thinking about it how can I test this application right now we don't have any domain let's generate domain to test the application uh if you want to refactor you can change that I can say Spotify clone production now we have this domain name I'm going to open it it is going to give me the nothing here don't worry when you try to access the API routes it will take some time because we have set the domain name it is going to take some time now it's working I think fine now after 30 seconds my project has Reloaded now we're going to figure it out I'm going to send the API request to test the application it is working fine now but what will happen if I try to create a new user let's say I want to perform database operation I'm sure it is going to give me the error let's create a new user Jane Don Jan gmail.com 1 2 3 4 56 I'm going to send the request I got internal server error you can check the log what what is going on users does not exist because my database is empty now we did not implement the migration remember you have seen in the data source we have set this synchronized to false but do not use synchronize to true in production what we have to do we have to run our migrations to perform changes we have to add relations because I done that I've done it I think I don't want phone migration you can delete that now I have to execute these queries these queries will create table in our postrest database here here what we have to do we got to run the migrations I got this issue we have to migrate the database in the production so we have to use a migration make sure you are using the password process. env. password not a DB password because we have defined the password in our environment file we have to run the migration I'm going to run the script npm run migration I would like to create all my tables that's why I just provided the name in it so I got the undefined process. I'm doing the log for node environment I'm also doing the log for DB DB host I'm also doing the log for DB password you can see that I got the development value it is working fine but when you look at the env. development I'm using the database for the Local Host like post gra local instance here I'm using the railway postra instance so I have to tell to nestjs build command under the they are using generate command is using njs build command this one type orm but I want to say please run the produ run the project in the production let if you want to run the de in migration in production you have to Pro tell njs project you can create a separate script for build for production or separate SCP for separate script for build in the development environment but you can do quickly by using say that export node EnV here I want to set the node environment variable to production now you can see development environment should be in the production I'm going to run the migration I've also logged the node environment it should give me the production by default it if it if it logs production it means it is going to run the production EnV this one you can see node environment is production but I got DB host is empty undefined and password I figured it out the issue I have to install do EnV package and here we have to use the EnV package it is not getting variables from EnV because we were using the config module for config configuration after installing config module do EnV package you have to import it here do en/ config now you should be able to access these variables so I'm going to run the migration before running the build you have to set the node envirment do you want to run it for production or do you want to run it for development but if you want you can create a separate script SE separate build script for production and development I still got the eror production it's not getting the value I think it is not finding the env. development file so there was an issue it is not loading the EnV from the env. development. env. production if we will have simple. EnV then EnV package can get variables from the file but right now it is not getting it so you have to provide the custom path I just did a little bit configuration we have to import the path we have import the part so we have to use this syntax require this one all I have to do is provide the EnV path now it should work it should get the values so I'm going to create the migration cannot read property PA is equals to path but I got still undefined let's log EnV path oh it is getting the value from DB but my file is located at root folder so it is not here inside the DB if I try this one I tried to work with this env. production with custom path but it is not working all I did if I change EnV it is it will work let's let me show you get rid of everything now if I copy that and create EnV file in the root directory it will work I found there is an issue with type orm now I'm going to paste my code for production you you have to adjust nestjs build when you try to run the migration you have to update the changes here I found this is the way you can implement it but there was an issue with custom file path so now it will work I'm going to run the migration now I can see production and the my container name which is my DB host and my password now migrations has been generated successfully it's time to run the migration we got to run this command npm run migration run should be run you can see that it is running all the queries creating tables in the railway postris database now you can understand you can use this EnV for type orm build use it for type or RM migrations because in the app module we are using the configuration of config module we are not loading this EnV file we are loading envir environment development env. production file but you can use this EnV for migrations now we need to double check it we have to deply our code now it will take some time to redeploy the application the application is running now I got this secret key the database host and the password now we're going to run it/ API open this Swagger tool you can also double check it from postris database I have only migration table it should give me all the tables but something went wrong here inside the migration the record is empty table is empty unique key primary key what is going on oh I have two migr ations get rid of this file get rid of all these migrations let's generate the migrations from the scratch I'm going to name it to in it now migration has R it successfully I'm going to comment this code now you have to run the migration everything is good to go all the ques has have executed now you should see the data in the data datase you can see I got artist playlist songs and users table we have these columns if you want you can run the seed from App module I think we we were doing seeding in main.ts file you can enable this code application is running now let's create a new user amazing we have created the record successfully you can also double check it from the post database you will have the user here but I created this user from the this one from seeding because I think my seeds are running constantly I think I enable that seed in the app module we got to disable it otherwise it will generate more users I'm going to remove them now you have to see constantly a new data I can say disabled seats now it is going to redeploy the application so this is how you can deploy nestjs application to railway in this module I'm going to teach you how to do unit testing integration testing and end to end testing for nestjs application before getting started on testing I want to teach you some of the basics of just because we're going to write a lot of mock functions we're going to write we're going to write a lot of spying spy functions you will learn how to create Mo implementation of service of a controller of a repository if you know the basics of justest if you know mo functions if you know spy function then you can skip these three lessons if you want to refresh the knowledge of just you can continue this video just as you if you don't know about just just is a popular JavaScript framework it is developed by Facebook you can use for testing JavaScript application you can use just with react view angular and nodejs these are all the function alties of the Gest asynchronous testing code coverage snapshot testing moing and spying we're going to use a lot of moking and spine with nestjs that's why I want to teach you these two concepts in more details you will learn how to do matches and test suits and test running and assertion uh before creating the just project I want you to open an empty folder we're going to start it from the scratch and you got to create package.json file I can say npm in it d-s please create the package.json file for me I got the package.json file now I'm going to copy that and let me replace that here what I want to say we we need to install the typing of the justest we need to install the justest app a Dev dependency and I created the script to test the justest if you want to run the justest in watch mode I'll teach you how to do that you got to run you got to run this script so uh please install these two dependencies I'm going to install them it's going to install the dependencies let's create a new file I I'm going to name it to some .js file we're going to test this function we're going to write test cases to test this function in the third step we have to create some. test.js file I'm not using typescript here I just want to show you the basics that's why I want to keep it more simple we have to import the sum function from the sum. JS file I have to write the test case at 1 + 2 = 3 now we're going to write the test case you can use the test it should give me the result 1 + 2 = 3 so we're going to call this function it's going to take the call back function I can say expect it's not giving me suggestion because it is taking too much time to install the dependencies because I think my internet connection is slow right now so we need a function sum. 2 B 3 we have to call that function it is going to take two arguments if you look at the sum. JS file you will see two arguments A and B the first argument I'm going to provide one and the second argument I'm going to provide two let's try to test it out it's still working npmi minus TJ my both packages have installed just in the typing of the just now you can write the test case I've written the test case you can run it npm run test I would like to run it in the watch mode dash dash watch is not sported so you have to write the watch all now you can see that I have to update the script for the watch all now we have to select the pattern I would like to run this s test.ts file right now we have only single file it's going to execute this file the test has passed now if I write the invalid value I save the changes it has started automatically and I got the error expected four but received three you can play you can play around with multiple matches function let's say 1 + 4 or to have been called to have property to have returned to have returned with let's say five you can play around with multiple watches received have as type number so this is not a right matcher function so I can say it should be five this is how you will write your first test case now I'm going to teach you the concept of mocking we're going to play around with mock functions Auto mocking inest refers to the automatic creation of mock implementation for imported modules or dependencies during testing let's create the mock functions you can use the mock function to track the function calls if you want to remove the dependencies we're going to do in njs testing we're going to remove maybe the implementation of service implementation of the service then we will have more implementation we can simplify the testing and control behavior when you do the unit test your code let's say if your code is dependent on five dependencies let's say if your class is dependent on on Class B Class B Class C or class D let's say and you want to do the unit testing let's say this is the class A now Class A is dependent on let's suppose Class B Class C and class D now Class A let's suppose we has two function or one function if you if I want to test the one function from the class A when you do the unit testing you test the individual Parts you test the individual functions to test the individual function maybe the individual function of Class A is dependent on the function of Class B function of Class C and the function of Class D then we have to write the mock implementation for the class B Class C and the class D I'll teach you in the later videos now we're going to create mock function this is how you will describe or you can group all your test cases into a group describe I want to write all the mo function examples in this section it is similar to the test you can Define the it or the test it is referring as a test so it should create the basic mock function let's create a new file Mo function. spc. TS file I have created the test.js file but you can also create the spec. JS file the concept is same now now we have to write the mo function here I can say I will provide the mo write Mo function examples here this this this section will have the mo function examples let's write our first test case it should create a basic Mo function should create a basic mock function you can create a mock function by using the just. function I can say this is the mock function just provide is a FN now we have the empty Mo function if you log the mo function you will see this is the empty function let's try to do it run the script again to run the Tex test in the watch mode this time I'm going to add the pattern for the more Dash function. spc. file it is going to ask me the pattern I can say mock now it's going to run this file if you see the log you have a function a mo function if I call that you will see there is nothing here we have undefined function if you pass the argument it is going to still it is going to still give me the undefined this is the empty mooch function if you want to return the value from the mock function you can also do that return value Mo return value now let's say I I would like to return the four now if I call that function it should give me the value of four I can write the match functions on it mock I call the function to be the value should be four you can see our test has passed now if I add the invalid value which is three it's going to give me the error expected three but received four if you want to remember I told you you can also keep track the calls of the function with the help of Mo how many times this function has cost called mo. calls. length to be we have called only one time so it should give me the length is one if I call the function two times Mo function dot to have been called been called let's say I want to call that function and I'm expecting the four it should give me the error you can see that the save to expected is one here we have the error it should give me the two because we have called this function two times if you want to keep track of the calls of the function how many function have how many times you have called the function you can also do measure on that here I can say expect mock function to have been called it is checking that did you call the function yes we already called two times this is how you you can return the value from the mock function you can create you have learned how to create the basic mock function now you're going to learn how to create a basic Mo function with arguments we did not create a function with argument we just created a basic mock function then we have returned the value here I can say it should create a mock function with an argument let's create a function con mock song function you can say song mock just. function it can have create song dto let's say that mock create song and this function will have this argument but I also want to write the implementation you can do that as well well right now we did not return the value if you want to return the value you can do this stuff it is going to return a song title animals and ID or you can oh animals and ID which is one let's say that that if I am expecting on that it should give me the same object animals ID which is two or ID which is one if you want to test the object you can use this two equal expression make sure you have called that function with argument create D is not defined title should be animals create D is not defined I think it will not not work we have to write the implementation here I just want to show you the another alternative path it's a call back function it's going to it's going to return the create song dto now you can look at this one now my test has passed now if I will write the ID it should give me the false it should give me the false value or it has failed because I am just returning the ID but you can pass this test if I create if I return the object use the spread operator and ID which is one let's try to check it out out now my function has my test has passed now if I provide the another value lower in our application this function like create song function does not exist here we don't have a create song function we don't have njs project we don't have repository we don't have service controller that's why this is how you can create the mock implementation you can also create a mock function with mock implementation we used callback function here here but if you want to use this Mo implementation you can do that as well it should create a mock function with an argument with Mo implementation this one I don't have preer file R see single C to true because I use this prettier formatter now my code has formatted now we're going to use the same approach const mock create song just. function I have defined the function mock create song do mock implementation create song dto it's going to return the object create song dto and the ID which is one now I'm going to ex run the mat to test the code my code has passed now my test has passed now you can approach you can implement the same stuff by using the call back function here or if you prefer the mug implementation you can do in this way now I'm going to teach you how to create a mo function and it function this function should return the promise all you need to do is call the mo result value we use the mo return value you can do that with the help of Mo resolved value let's say I would like to create a new function let's create a new test case it should create a mo function with promise ultimately it it is ultimately it is going to return the promise fetch song data or you can say that fetch all the songs from the DB or you can say the network request now we got a return Mo return or Mo resolved value let's say fetch songs I got the array ID one title Lover now I will like to call that fetch songs Doc do results dot to equal if you want to apply assertion on promises you can call the results property and then I can apply this Expressions to equal this one make sure you could to call that function now my test has passed if I write fetch I'm going to call the fetch functions do resolves dot to have length it should have one my test has passed if I write the two it should give me the error because we have only one property in the songs array I got the error I'm going to call it with one this is how you will do the mocking you have learned the feature Auto moing which is mock functions but we did not talk about the spank and you can control the behavior and you can assert on their usage during testing you can create the function spying on spy you can spy on a function by using the just. spy on it allows you to create a spy or a mock function for an existing object method if you want to spy on existing object you can do that if you want to spy on existing class you can do that now we're going to spy on an object we have an object spy on a method on the object we going to Let's imagine we will have the song repository and we have the create method what I want to do I want to spy on the create method I don't want to use this implementation I want to use my fake implementation in under the hood just will tell you you I called this function but I have used your implementation this implementation this one instead of instead of using this original implementation let's spy on I want to I want you to create a new file since by on demo dopc dots let's create a song repository and we have a create function let's imagine we have a find function let's imagine we have the find one function I want you to add the add this Pi on this find find and find one but first let me do that find one will accept the ID let's imagine the ID now let's create a function so I created the test case it should spy on the existing method function object method so you can create a function on this py on so this is how you will spy on the function it should also give me the toll tip create if I log this piy function let me show you what is inside that I have to run this file P I want to spy on it's going to run this file my test has passed but this is a mo function if I call that it should give me nothing because it's an undefined what what if I call the function SP and I'm going to call it not an ID let's provide the title or let's say if I call the function function of this song repository you will see the magic I have called this function now my function this function is pying on this function what will happen if I log spy do mock do calls it should say I have been called with this argument array it's an array mo. length which should be one it is saying I've been called only one time by using this one if I call song repository. create let's say title new song now the length should be two you can see that if you want you can spy on the function spy do to have been called now my function has been called expect spy you can also say that to have been called called with called with title should be lower it is fine now if I say lovers it should give me the error you can see I got the error you can also track the how many times this function has called to have been being call times it's going to give me the one I'm spying on this function song repository. create similarly you can spy on the find and the find one you can also spy on a class I'm going to create a new class we have let's say I'm going to place the Clause here we have safe method in the artist repository I want to spy on this function but you can also write the implementation just like we did it we can have our own custom implementation I call this method now you can see that to have been called times to have been called with at the end you can also restore the mo but I would like to do this one after each please restore all the mocks this is a hook after each it is going to run after all the test in this section in describe section now we're going to copy that test case and paste it here we have created a new instance from the artist repository and I call just. spy on I want to spy on the save function but I also want to add my implementation it is going to return the create artist dto or it is going to return you can say that I would like to return the object create artist dto and I want to add the ID now you can see that spy it is going to call this function artist. save what is here I called spy name and it has returned Martin Garrick and with ID which is one and how many times to have been called yes expector to have been called with name we provided the Martin garx spy and I don't need to do that because we are doing it here expect spym do calls. length how many times have you been called I think I did it one time rt. everything is to have been hold with two times also called artist. save and I also called it manually now it looks good in this lesson I'm going to teach you the concept of unit testing in nestjs when you do unit testing you test the individual component of your application individual component means individual function of a controller of a repository of a service we have song song service I have attached this started kit project you have to open it and run npm install you got to install all the dependencies we have uh we have this song controller when I'll be talking about unit testing I mean I have to test individually this function get song get songs create song and update song and delete song but you notice the song controller is dependent on song service here we need more implementation of song service because I want to test individually this song controller but when we will do end to end or integration testing when you will test the end to end you will integrate all of your services all of your classes all of your dependencies you can verify your unit of code such as fun s methods or classes with the help of unit test you can find the bugs earlier you can improve the code quality you can do faster debugging you can refactor all refactor code very easily now when you run the source code when you run the test for song control dopc file nestjs already created this spec file for us if you run that it is going to say hey when I look at the song controller I saw dependency There song service but when you are creating the testing module here we are creating the testing module on the Fly n sjs will compile it when it will comp compile it will instantiate all the dependencies for the testing module here it is saying I'm depending I'm dependent on song service but you are not providing any song service here you not providing any provider let's say you are not any provider song service so it will give me the error because we are doing unit testing I don't want to include song service here I want to test individually these components but I'll teach you how to fake how to create the fake implementation of song service here we are getting the controller from this module and it should be defined this is the first test NP you can run the test they have created the script for testing I'm going to use this one npm run test watch let me provide the pattern for song controller dopc now it is going to watch this spec file you can see that test has failed now here have you included song service in the provider no we no we did not if I will add the song service but still getting the error now the song service is dependent on the song repository but we will include all these dependencies in integration testing but I want to test the individual components so get rid of the song service I got the error so we need a fake implementation we got to create the mo service for the song Here is how you can register a mock service with the help of Mo implementation you have to register the song service and you going to provide the song service provider here you have to use the use value property to create the fake implementation object or the service you will have the get songs method inside the song service here I created the mo function and it is going to return the promise with this record let's try to check it out when I will open the song service we H we will have these methods get song is returning a promise get song is also you have to write the fake implementation or Mo implementation of the song service we need providers song service song service here we have to write the fake implementation get songs you can create a mock function all you need to do is return a promise with a value let's say ID is one title title let me check the song model or song entity we have one property which is title dancing feed now I have the mock implementation of get songs now you can write the test case make sure you get the service if you need I think I don't need that you can see that now my test has past now I'm going to write another test case it should it should fetch all the songs or you can wrap your code inside the describe fetch all the songs here I have to write this one or you can say if you need to write multiple test cases for get songs functionality you have to do it in this block now we have to call the function songs v controller. get songs it's going to call this method get songs you have to use the async keyword now we have to write the matcher it is going to give me the array of the songs to equal now we're going to copy this one a test has passed now get song should fetch all the songs now I'm going to copy all of the code for mock implementation for the methods of controllers it should add the create song dto it should have the update song dto what we have done so far I created the mo function with Mo implementation remember it is get it is getting the idea is an argument now it's going to return the promise here for the create song it is accepting the create song dto I create the ID which is a unique key and I have separate the separate the create Song D it's returning a promise similarly we have done for the update song we created the mock function with an argument update song dto returning the promise in song service for the update it is returning the update result so make sure you have this affected one and delete song what is an error oh I have to restart the project now we have a fake implementation of delete song now let's test this function get song by ID I'm going to copy that get song by ID you can provide an ID which should be anything get song Yes ID could be anything or I I can provide a unique key a uu ID you can see the test has pass now for get song ID now I'm going to copy the create song Let's test it we have created the new new song by using Create song dto we have to provide this create song dto and song. title should be run away because we are giving this argument here create function is giving me the create song dto with ID or you can also write another matcher to equal ID should be a uu ID ID and title should be Runway run away you can see that my test has passed now similarly we have to do the same thing for update song we are creating the update song dtoo by using the update song dto object I would like to update the title it should be defined and affected should be one update song you can see update song has passed now now we have to perform testing for delete song I just provided the ID you can provide any ID you can see that delete song has also passed now this is how you will test your controller unit testing for controller in this lesson we're going to test our service we're going to write unit test for service when you run this service you will get the same error because in this song service we have a one dependency which is repository the song Repository we have these so repository will have this we have to write the mo implementation for find method find one or fail save method and create method update and the delete because our service is using these methods from the song repository so if you write the if you run the test for song service. speec you will get the same issue this is the default implementation from nestjs Project they are using the provider right now we don't need any controller here we are doing unit testing we are doing individual testing for each function let's run the song service it is going to find the song service. spc. TS file the test has failed now it is dependent on the song repository but I did not provide here I did not register it so we have to create the fake or Mo implementation for song Repository what I'm going to do I'm going to copy this code we need these get repository and get song I have created a two objects song array song one song song and the song array this is how you will create the mo implementation for the repository we have to get the repository token here I can do that one thing make sure you provide the song service I forgot to do that in the controller Let's test it so everything is working fine now now we're going to test the service we have to import it get repository token I'm telling to nestjs this is my fake or Mo implementation for the repository song service for the find it is going to return the array we use promise. resolve Mo implementation for the just I'm getting the options as a find one options you can import it from the type orm we also need to import create song dto it is returning a promise with one song it is going to return the promise with a song newly created song and save method is just a simple Mo function it's not doing anything in update we need to get update song dto we have return the mo implementation and it is returning a promise with one song for the delete it is returning a promise with affected but maybe for the update you can give this response affected one now we have to test it if you need a repo you can get the repo yes we may need a repo I can get the repository by using get repository token let's test the method from the song service it should give me this song by ID we're going to test this method this one this one get song by ID this one it is using find one or fail and is using fetching the song on the based on ID so what I have I have done I created a new song I I got the song on the based on ID it should be Yu ID Yu ID so I'm going to spy on this find one or fail what I have done I called this method get song in under the hood this Pi this method this Pi just Pi will be spy on find one or fail it is saying hey you have called find one or fail from the original repository method and it has been called with this one this is how you can write the unit test now we're going to write the test case to create song I created this song and I'm going to expect it with one song called one time and you can say called with title lover let's copy the update let's copy the delete everything is passed now for update I think inside the song service what we have done update result so we have to fix it more repository it should give me the affected and the one result result do affected equals to affected one test has passed now if you want to spy on delete method how many times I have call delete method if you want to track the calls you can spy on that by using the Spy repository on delete method I've have been called this one time and it is affected one time I got the it means affected means one record has deleted successfully and it has been called with uid that's all for unit testing with service now you're going to learn the concept of end to end testing we're going to do end to end testing for our nextjs project end to end testing is a software testing methodology that focus on testing the entire application flow from start to finish now we're going to integrate all the song controller repository song service everything you can do API testing in end to endend testing validation of the user flow improved user experience now we're going to start doing the end to end testing first step we have to add the script in our package.json file they have written the script for end to endend testing but they did not add add the watch that's why I just addit the watch or detect open handle I I have written this line or keyword for to handle the errors if you will not at this line This one this word it will give you some type of warning messages the first step we have to register it the type or a module in the song and to end test here we have the end to end test this one this is the end to endend test for our generic application let's run it npm run test find the script test E2 e and the watch mode let's provide the pattern app it is going to run this spec file this is end to endend testing for app module going to create nests application and initialize it here it is going to test our root URL under the hood they are using the Super Test request from the Super Test making the API request by using calling the server this is the end point and it is expecting the 200 status code test has failed got expected 200 but got 4 44 but I would like to add the test case into to end testing for our song controller for song module let's create a new file here inside the test I'm going to name it to songs I can call it songs do E2 do- spec. DS file it is just an initial code you can copy that from the app do e2e testing I got this one describe it should be songs import couple of dependencies type or module make sure you have created the database for testing I created that with the test F and syn synchronize set to true you have to register entity manually it will not work with regular expression at the end of each or at the end of all test when all the test will be finished it is going to drop the schema we will have the song Mar is not getting the path I think so we have to do in This Way song Find song entity same thing here there is I got the testing modu that's it now we have to run it here you have to provide your username password and the Local Host Post Port in the name of your TP it is going to run this file I got the error you your test Suite must contain at least one test all right now we're going to test the code first step after each test we have to clear the repository because we're going to interact with database in the describe this will be run before all and we will have after each we have to clear everything from the song table or song repository this clear method will delete the records from the table but it will keep the schema schema this function or this hook will run after every test make sure you import the super test I'm going to write the test case for delete or not not a delete for create I just created a new method create song we have the song song. title song. repository and it is going to save the song in the real database right now we don't have more implementation for the song repository or the song service it is going to save the record in our real database we are using the test def if you don't have test def you can create it I have set the title get the repository instance from the app.get and called the safe method maybe you need to add a weight expression because we are returning a song with promise you can do in this way it will automatically get this promise with song let's write the test case before fetching these songs make sure you have the record in the database that is why that is why I created a new song with create song first you got to save the song in the in the postest database with title animals and then you have to send the API request to this URL doget and here I'm checking the status code should be 200 and the request body or the results body should have length one which should be have one record it is an array it is going to give me the array in results. party and I'm I have created a one song so it should be there there should be one song in our database so that's why I converted into an array after then when this test will be completed it is going to call this method clear the repository you can see our test has passed now if I write let's say 20 1 or maybe 400 it is going to give me the error hey I'm expecting 200 you can see I got the error so get song endpoints has tested successfully now we're going to get test get song by ID first we have to create a new song then I have to I have to send the API request make sure you have to send the ID I created this song because after each test it is going to clear the repository it is going to delete all the records from the songs table create a song then it's going to you have to provide the ID first I have created the song then we have to test it make sure the body should equal to this song I'm going to save the application it should pass two test has passed now now we're going to test update songs endpoint make sure you have to import it it should be it create a new song and you have update song dto I would like to update the animals to wonderful sending the API request this is how you will send the data to if you want to send the Json op object into the request body you can call the send method I want to send it as a update song dto this one I want to update the title which is wonderful status code should be 200 and affected should be one it means our record has updated successfully and let's do this for post we have this is our create song dto we did not create we did not create the song right now I'm going to use the create song dto provide it as a request body the status code should be 2011 and the title should be animals for test has passed now we have to test the delete song endpoint let's create the song first and then we have to provide the ID which record you want to delete status should be 200 and the affected body should be affected should be one it means record has deleted successfully this is how you will write the end to endend or integration testing with database or the nestjs application nestjs version 10 has released now I'm going to show you how to create new projects with nestjs version 10 version 10 is very fast they have integrated the rest rust compiler they have integrate the rest to compile the source code sjs if you Google the version 10 you will find the blog post from the owner of the nestjs they have released version 10 in the version 10 you you can compile the code in a faster way like it will also improve the hot reloading you can you can do development in the more fast way to start a project you have to add this command we we're going to use this options this one we will add these options into Nest CLI they have also introduced a new feature this time you can Mo the entire module instead of provider and controller these are all the new features in the nestjs version 10 but the main feature is improving the compile code speed of the compiler but let's create a new project first of all you have to remove or uninstall nest jli because you will have have the older version of n CLI I'm using Mac so we need to add the sudo keyword instead of install first we need to uninstall the nli I have already installed nli can I check the version of this package I don't know let's try to look at that I have 8.1.0 I have I have the latest version but it will generate the nestjs 10 project Nest new and we have to provide the name of our project I can say web socket implementation nextest let's do it again nextest new the name of the project websocket implementation I would like to use the npm it will take some time to install these dependencies my project has created I can look at by going to this directory I would like to open this project into my vs code editor if you check the package. jsn file you can see we have the nest version 10 now what I have to what I have to do we have to compile the code faster let's first we have to run the project without this command This One S swc Speedy web compiler first we have to run it without Speedy web compiler you can look at the time for running the project when you will have multiple modules you will have multiple controllers and you added the testing functionality your application speed time will be slower your development time will will be slow so let's make it faster with the help of these two options I want you to add these options into package into nli n c. Json I'm going to add these two options to my compiler these two options Builder I would like to use the S swc and type check let's run the project you can see that I got the issue fail to load fail to load s swc CLI and S swc core we got to install these two packages let me execute this command install it as a def dependency because I want to improve the project running time increase the development time so packages have installed now we need to run the project now it can take the S swc it can use this Builder and type check our project is running the project running time has increased now if I save something in our application let's say in the app controller in the app service hello world from nestjs version 10 I want to save the application successfully compiled this is how this is how you can improve this implement or in improve the development time the project running time in development environment in this module we're going to work with web sockets when you want to implement real to real time application like chat web application real time web analytics live streaming online gaming then you need web socket which we have worked with HTTP server in HTTP where client sends the request in the server response but if you if you're using web sockets web sockets establish a persistent connection between client and the server and you can have ongoing communication the best example is Facebook Messenger you send a message to your friend and your friend rep replies and you reply to your friend and your friend reply this is how the bir directional communication Works in under the hood they have implemented the websocket protocol they are using the websocket technology if you need to make persistant connection then you need websocket you want to implement a realtime feature like live updates live score live streaming then you need websocket here is chat application can be built with web socket collaborative editing tools real time analytics online gaming and the live streaming nestjs also provides websocket module you can use that but it also provide two approaches you want to do you want to work with socket iio or you want to use the web socket you can get the details from their official documentation but in this video I'm going to implement the socket IO you got to install these two packages I'm going to open my package.json file let me add my dependencies I think I already installed these two dependencies I don't need to do it again you can do it manually by running npm install and first install this dependency and then you have have to install these dependencies our next step is to create the events module we will have the Gateway a Gateway will be responsible for handling the events you will have the events module a Gateway is nothing more it's a class with provider you can inject it as a provider here we we need this Gateway we're going to create the event Gateway it's nothing more it's a class here you have to decorate with websocket Gateway I'm allowing any origin you can use any specific origin if you want here I'm trying to implement the own module in it when any client connected to my application this event will be triggered this is how you will register the event by using the own own function I can also get the socket ID I can also log that have has it connected or not this is how you will create or register a new event subscribe message and we will have a function new message you will have the message body you will get the data if someone sends message or filed an event from the client side application like react angular view or any kind of front- end application this function will be called but make sure they have called this event with message key this key and it is going to lock the data you can read this text here for every detail let's create events module we have created the events module now let's create the Gateway you can see we have the events module Gateway will be registered as a provider you can see in the events module we have websocket Gateway by using this decorator and we have one event if you want you can add the CES and we also need to establish a connection I need to check make sure you imported server from socket IO Library you have to import it manually otherwise it will not work websocket G websocket server now we have this handle message subscribe message when you need to register an event in backend application or the nestjs application you will use the Subscribe message decorator and what I would like to do I want to get the data or you can have client but I like the data I don't have any payload option but I'll use the message body decorator instead of use this one message body data should be type any I'm not going to return any thing right now all I want to log the message I can say message received from the client and this is my message or I can log the data so far we have registered the event when any web application like any front-end application has connected to our websocket server first they need to connect on the our host here we have provided but right now we're going to run the project on Local Host so any front end application should connect with Local Host colon 3000 and then he can establish a connection between with with this application when when any front end application establish the connection it's going to call the own module in it but right now I don't have any own module in it right now it will log this message implements on module in it that's it after module loaded or this file is this class is loaded successfully then we can log the message when connection established this event will be triggered and it is going to call with socket I ID and the connected its Boolean value now we have set of the websocket server and we created our first event which is message you can have multiple events here you can also perform the DB operation like if someone sends a message you can save the message into database in the next video in the next lesson we're going to consume this event from our frontend application we will have a simple basic front end application with index.html and there would be JavaScript in the index.html file now it's time to consume the application consume the event or send message from the frontend application when you run your server let's say npm Run start def now my server is it's ready to listen this message event it's waiting for someone to send a message by using this event key so all you need to do you got to create a basic index.html file you can copy that code or you can create manually I can say client here I will have index.html file one more thing you will see events Gateway subscribed to the message event to this message so it means we successfully created the event I'm going to copy the code I'm using the socket IO Library where we are creating the socket IO instance by providing our application path in our case we have nest's application is running on Port 3000 we have registered a event it's trying to connect with our application with nestjs application when it when it will be connected it is going to log this message and emit this message to the server here I'm going to open the server this one events Gateway we have registered the message event this is how you can emit the event I'm telling to socket IO please call this function that's it and we also registered couple of events if someone if if server sends data back to the client we have to register it we have to catch the data here that's why I use the on listener if exception event trigger it is going to call this method if if our backend application disconnected or stopped it is going to call this event it is going to trigger this event now we right now we're not returning anything here let's try to test it uh I'm going to use open Live server go live when you open the index.html you will see this it is going to open my project into live server please check the console for message reply inside the console you will see you have connected successfully when you open your backend application this message is received from the client so client has sent this message or you can say I am the client I'm going to reload the application it has automatically reload reloaded you can see I'm the client so it has also connected one more thing you will also see this socket ID and it has it means connected successfully first it is going to log this message console. ID Lo connected we have emitted this message event it's going to call this function now we we are not returning anything that's why this event is not triggered let's try to return from return something I'm going to return some value let's say some value from server let's see what will happen our application reloaded let's try to test it out message received from the client but I did not log what message have you received you can see message received from the client on the client side we sent this message I'm the client it has received but it is not triggering this event I cannot see anything here let's say if I if I'll try to log something hello I cannot see this Hello message in my console it's not triggering so that is why you need observable websocket also provides the observable you can say I would like to return this observable websocket response and I can have any type here we have to convert the object to observable that's why I'm going to use the off operator from rxjs I can say event you got to provide the name of the event which is message and the data here you can return anything from the server message returned from server hello you should see this message here because we are listening on the client side you can see event message received from the server if I will refresh our application you will see this one message returned from the server hello if I stopped my application it is going to F this or trigger this disconnect event you should see the disconnected this is how you will create wi directional or realtime chat application with web socket in this lesson I'm going to teach you how to set up graphql server we're going to use Apollo server nestjs Apollo package nestjs graphql package graphql and TS Mor you can read the documentation of these packages I'm assuming you must know the basics of graph ql I'm not going to teach you the basics of graphql what is graphql and why do we need graph Q I have attached a started kit project you have to open it and run npm install I have already I have already installed all these dependencies I don't need to install them again all I need to do is to install graphql packages I'm going to copy all of these packages the packages have installed successfully and now the next step we have to register the graphql module I'm going to open my app module and we I would like to import graph module here we need to import couple of dependencies Apollo driver config I'm telling graphql hey I want to use Apollo driver and I will have do graphql file where I will place all my schema definitions in the graphql file this file will have the typescript typings of graphql and output as a class don't worry I'll Teach You How can you generate the typings we are using for RO to register the graphql module the Apollo driver config specify the type of the configuration options being provided so driver AP poo driver this property sets the driver used by the graphql module in this case we are telling graph Nest chairs hey I want to use a polo driver we will place all of our graphql schema in graphql file the extension should be do graphql uh if you want to generate typescript definition from your graphql schema you have to specify these definitions I'll teach you how to do that and we are just combining the path we will have so graph. TS file inside the source directory this property specified that the generated type script definition should be outputed as a class this means that the generated code will be representing represent the types as typescript classes now our next step is to create a schema file inside the song folder I'm going to create a new file song. graphql here I will place all of my schema file we're going to have a query let's define a song type we will have ID and the type of ID is required this means it is a required property it should not be null and I'm going to add a string variable or string type field which is title the type of the title is string and I'm also going to add a new query type here I can say I want to fetch all the songs and you can say the type should be song and it is going to return all the songs our next step is to generate the typings which is typescript definition file we need a graphql definition Factory class here we are trying to in we are instantiating or creating a new object from graph definition Factory there is a generate method to generate the typing you have to specify the type which is I'm using the regular expression here I will have all of my schema file in the cql that's why I use the type definition path and I would like to I would like to create all the type typescript definition in the graphql dots file it will save it as a class let's create a new file generate typings dots file inside the root directory typings dots now all you need to do is to execute this command NPS npx DS node generate typings it is going to generate the graphql dots file with this definition you can see that a graphql dots file has created we have a class which is song and we have a abstract type which is I query and we have this type so we will use this type definition when we will creating disolver functions when we will resolve queries against your schema files now I would like to run the application is everything fine now let's test it my application is running now let's send the request to Local Host colon 3000 and you will have playground at this graph quel Endo when you go to the Local Host colon 3000 you will see the playground this is how you will perform graphql apis you will test graphql apis by using this playground let's say I'm going to send the API request graphical API request I want to fetch all the songs I want to see the ID and the title but it is going to give me the error hey you don't you are not resolving this query because it's returning n it's getting the validation eror because we don't have any resolver to resolve this query this one in the next video I'll teach you how to create mutations and how to create queries we're going to we're going to fill our song schema let's complete our schema let's create a new query to fetch a single song when you try to fetch a single song you must need to provide the ID so ID should not be null and it should return this song in the response let's write a new query it should give me the song and I would like to fetch the the song on the based on id id should not be null now we're going to write uh venue query in the playground you got to follow the structure song and you have to provide the ID in this case I'm providing the 1 2 3 as an ID now we're going to Define mutations we learned how to fetch data with the help of query but I want to write the data so to to mutate the data you need a mutation so let's define an mut mutation mutation I'm going to have create song it will accept the create song input or create song input and I don't have any type so that's why I'm going to define the input create song input I will have the title field and the type should be string it should not be null so I can say the type of create song input it should be create song input and it should not be null and it should give me the song in the response now I want to write the mutation for delete song or you can say update song I would like to update the song Only the based on ID the first argument it should be ID and the update song input we will have update song input it should give me the update result this is not an empty field that's why I use this exclamation mark and input update song input title should be string but I did not mention it to required property if you will have multiple song multiple fields in song let's say a user will have let's say a song can have date or you can say date release date or publish date or artist something like that but I cannot set date required in the artist required field because it depends on the user a user can update the title or whatever he wants to upate update now I don't have any type for update result let's define a new type update result it will have affected and type should be number do we have int yes int similarly we will have a type for delete result delete result and typ should be int now we're going to Define mutation for delete song I can delete on the based on ID here I can say delete song I don't need to put anything and it should give me the delete result that's it so we did not resolve these queries in mutations in the next video we're going to write resolver functions to resolve these query and mutations Let's test it out by generating the type one more thing I want to show you can create a script to run the typings I can say in the package.json file let's define a new script we here you need to define the script generate slash colon typings TS node generate typings this njs project all already installed TS node as a def dependency you don't need to install it again npm run I can say generate typings it will generate the typings or types in the graphql dots file I found an error unknown type create song input did you mean create song input or update song input oops I have to fix that everything is fine now let me see my graphql dots file we have type for create song input type for update song input we have types for mutations and update result and delete result when you see your playground you have to look at the queries in mutations we have queries and mutation when you try to fetch let's say I want a query for songs ID let's say I'm going to provide invalid ID let's try to fetch the title and the ID I'm going to send the request it should give me the error hey you are not resolving that's why we need resolver I can use n CLI to generate a new resolver I can say song it's going to create a new resolver resolver is nothing more it's a provider like a service you can inject it as a dependency here you can see that inside the providers we have a song resolver and it is it also created the song resolver dopc file and song resolver we have resolver Tator now I'm going to resolve these queries I'm going to open song do graphql let's resolve this query I also need song service so Constructor private song service song service let's import it I have this I need a query decorator here I would like to resolve this query songs I can say get songs return this do song service dot get songs and you can also mention your return type I can get it from the song entity or song graphql type this one make sure you are using the Asing here what is saying unable to resolve the signature of method decorator when called as an expression oh we need to get the query from nestjs Craft ql now it looks good let's try to test it out let's try to resolve this query I would like to fetch all the songs you can see that we have a song I already created a song If you don't want to see the title you can say I only want to see the ID but I have single song in my database now let's resolve the query to fetch a sing single song I Can Say song async Get song it should give me the song with promise this do song service dot get song you need to provide the ID but I can get the ID here I can use the arcs from the N graphql I can say the id id is string let's provide the ID here I have saved my application let's try to resolve this query I want to copy this ID and let's fetch a song ID should be this one and I'm expecting the title in the response fail to fetch please check your connection I think my application did not start it now I have to send the request I got my record which is song on the based on ID if I provide the invalid ID let's say you will see the error invalid input Syntax for the type the ID does not exist as same here now I'm going to provide the correct ID I got the record you have learned how to resolve queries in the next video I'll teach you how to resolve mutations now you're going to learn how to resolve mutations in the previous video we resolved our queries let's resolve these mutations create song update song and delete song now you need mutation instead of query we also need create song dto as An arcs or you can say create song input you can also do that you can also get this typing from from graphql file and I just called this function it's not finding source. cql we have to do it manually now it looks good it is taking some time to in restart the server let's create a new song I'm going to write mutation create song create song input we have to provide title the name of the song which is follow me I want to see ID and title in the response you can see a new song has created I can fetch all the songs and you can see follow me it means we successfully created this we have successfully resolved this create song mutation now it's time to resolve update song mutation I'm going to copy this one update song we need to Res solve we need to get update song input update song dto or you can use update song input from graphql file I also need to get update result from graphql it is saying I'm getting the error update song If I get this from from typ orm let's see what will happen now it looks good because this start update song it's returning the update result from type orm when you look at the update song you will see the Promise with update result I imported update result from typm let's try to update the song I'm going to write mutation update song we need the ID I'm going to copy this ID let's place it here and we we also need to provide update song input I would like to update the title update song Let's fetch all the songs and you can see the updated song similarly we need delete mutation let's resolve it I'm going to copy it here delete song we have to get it from the type orm let's try to delete this song mutation delete song we need to provide the ID I'm going to copy this ID let's see affected delete song successfully executed it should delete the song let's try to fetch the song on the based on this ID you will see there is no song here you can see there is no song in this lesson I'm going to teach you how to handle errors in graphql let's say I want to fetch all the songs but instead of returning all the songs I have to return the error you can do simp simply by using throwing the error or you can say let me do this in this way I'm going to comment this line through new error I can say unable to fetch songs let's try to send the graphical request it's still working my application did not reload yet let's wait now it has reloaded you can see unable to fetch the songs I got the error internal server error uh if you check the Apollo documentation we are using Apollo driver Apollo driver is saying you can use the graphql error class and you can provide your own message Apollo Apollo Apollo documentation is saying they also provide buil-in error codes like Parts field graphql validation field Pat user input bad request we're going to use this error bad request all you need to do is to throw the error and you going to provide your message in the code so let's use the throw the error new graphql error I got this graphql error class from graphql package here you can see that now first I have to say unable to fetch the songs you have to provide the options you can provide the code you can say server error or what what type of message you want to use it depends on your use case I can say internal server error let's try to test it out I saved the application it will take some time to in reload the application application has reloaded let's send the request and I got the error unable to f F the songs and I got internal server error this time you can see graphql error unable to fetch the songs you can also see the message I got the error at song resolver doget songs you can also check the error stack get song song song resolver doget song we have the error at this function get songs this is how you can send the error in graphql if you want to use your own custom message you can also do that you can provide your custom message your custom code and your custom extension you can also set the HTTP status if you're working with HTTP API you can also set your HTTP status code and some type of headers in this module you're going to learn how to apply authentication in graphic SQL we have implemented authentication with rest API now I would like to implement authenticate graph cuel apis in the previous module you learned how to create graphel apis with nestjs I'm going to pick the same example project just like we did with authentication in rest API I have provided the starter kit code you have to open it and run npm install when you install all these dependencies you can run the project and you will get this error let me run the project because there is no graphql file there is no graphql extension file when you open the app module you will see the graphql setup we have a graphql module I'm creating a graphql module by using the Apollo driver just like we did with in the previous module I'm using the context I'm just returning a simple request mapping the request into request it's nothing more I'll teach you more about when we will protect resolvers so I've already taught you all of these stuff like we created the OD service we have a login method here we have a JWT guard I taught you how can you do that what type of implementation we have done we have passport strategy with JWT it's validating the user and we have dto login dto everything everything I have taught to you if you don't know about all of these functionalities you can go back to the module number six on authentication you can watch the first four lessons on authentication or first three lessons on authenticating nestjs apis you will get the error no definition found no type definition word found because we don't have any graphql file I just did the graphql setup first of all we're going to set up our we're going to define the schema we don't have we don't have any schema what I want to do I want to do schema in O folder let's create o. graphql what we are going to do we're going to create the user type and we're going to Define query and we will have mutation for sign up mutation and we will have login mutation first of all let's define a user type the first argument is ID it should be required not null first name the type should be string I can get this value from the user entity you can open the user entity on the right hand side right side first name is required last name is also required and email is also required and password is also required so we need these properties these five properties I'm not going to play around with playlist something like that let's make it more simple we defined a user type now I'm going to define a mutation sign up it is going to take the signup input and the type should be signup input we did not create it yet it should be required and it is going to turn a user back in the response or sign up response we not we did not create this we did not create this signup response type now let's define a new type with signup input when you when you sign up we are telling you need to provide hey client you need to provide the first name you need to provide the last name you need to provide the email email is also required password is also required now let's define the sign up response sign up response what you want to send in this signup response you can send a simple email it depends on you I'm going to send a simple email now we're going to Define query we have a mutation let's define login query I can say login it is going to take login input inside the login input and it is going to return a login response we did not not have these type yet it's are required let's define an input I'm going to Define input here login input we need email type should be string we need password type should be string and we also need to Define login resp response I want to send the access token you can double check it from your OD service or user service we have a login in the login we are just returning the access token here you can see that access token the type is string we're going to follow the same convention the type is string it should be required we created the login mutation that that's it let's try to test it out by running the mutation or running the typing command npm run generate typings it is going to generate the typescript definition file typescript definition file has created you can see graphql do s file we have all of these typings we have created or defined our schema in the next video I'll teach you how to resolve queries and mutation we're going to work on sign up mutation first in the previous video we have created this sign up mutation now we need to resolve this signup mutation we don't have resolver inside the O module let's create a new resolver we have to provide the name which is O Au resolver has created you can check inside the Au module we have Au resolver we have spec file and we have Au resolver we have to resolve our signup mutation mutation which is sign up I'm going to open the autra ql here I want you to do it should be sign up user I'm going to define a new function and it is going to return a sign up response you can get the typing from graphql dots file and one more thing we need to inject service user service and OD service we need both of them user service and we need OD service we have a create method let's get the argument I can use the arcs we need to get sign up input and I can say sign up input you can also also get the type sign up input and I'm going to provide sign up input everything is fine now let's try to test this signup mutation I'm going to run my application my application has started and I got the error sign up defined in resolver but not in the schema oops there is a type typo Here sign up we have to generate the typing again npm run generate typings everything is up to date it is taking too much time because I'm using no nestjs Version 9 because I built this project in module number six by using the nestjs version 9 that is why it's very slow I have to oh let's restart it again my application has started I'm going to send request to the Local Host callon 3000 and/ graphql if you check the docs we have a sign up mutation let's create a new user first name make sure you have database in your postgress let's provide the last name let's provide the email let's provide the password I got the error because I did did not select any field here I would like to select the email because I can only access the email I think I already created a user with this email let's use new one there is an issue reading password let's try to check the error password is invalid why let's try to log sign up input what it is getting or do we have sign up function here inside the OD service do no we got to use the user service. create let me check in the Au controller what we are calling what we are using user service. create that is it I'm getting the undefined maybe there is an issue in autra Q let's check it out oh syn sying up input my God sign up input sync input sign up input let's run the project let's update the fix it sign up input we also need to update it here sign up input run the project Let's test it out by sending the request to create a new user sign up input we also need to update that we have created a new user a user has created successfully you can see that we got the object let's log in I want you to implement it I'm going to copy that we need to get the query from nestjs graphql package we also need to get login input and the login response we have a typo here aouc I need to run the typing again let's run the project let's try to send the login request I'm going to copy use email and the password I need to get the access token we have successfully logged in because I got the access token in the next video I'll teach you how to protect resolver we're going to create a new protected field which is profile only authenticate user can access this profile we have created all card this one JWT o card we have to use this o card into our resolver I'll teach you how to do that but I want you to think about how can we implement or how can we apply JWT off card we have completed the sign up and the login functionality let's say I want to protect resolvers when we were building the rest apis if you look at the app controller I can say this is the protected route only authenticated user can access the profile and here we also getting the user from the request object but you are thinking about how can we protect the resolver let's say I want to write a query profile and type should be profile we don't have any profile type let's create the profile type the type should be string the field should be string and here we have the user ID let's generate the typing when we resolve this query only authenticated user can access this profile we should not allow anyone to see other person or other people profile how can you do it when we were building the rest apis we use the JWT guard we have created this guard and we apply when we applied this JWT o card on our protected route just like we did in the app controller this is my protected route the profile route and I have applied the O card by using the use card JWT oard maybe you thinking how can we do into graph well I'm telling you I'm you you also need God you also need JWT o guard I want you to implement it you don't need to change anything in the JWT strategy because we were using the passport strategy if you are not sure if you don't know about how did I implement the passport strategy you can look up the Authentication section I think it's section number six or module number six or seven and then you can get the lesson for passport or jwd authentication it has generated the typings in the graphql dots we have the profile class now when we resolve this query I have to say hey this is protected route let's let me show you I'm going to run the project to access the protected route a user or client should or client must need to provide authentication token the user can get authentication token by executing or sending the login request and this login request gives the access token in the response let's wait for the application my application is running now let's send the request to the Local Host col 3000 /ql here you can provide the authorization HTTP header I'm going to send the login request I got the access token here you can access the profile route you have to provide the token here we did not write the resolver for the profile query let's resolve it inside the Au resolver let's resolve Au query or profile query get profile it is going to give the promise with profile and here is the question how can you access the profile or how can you access the current logged in user like we need to send current logged in user actually we need to send the user ID the current logged in user ID and his email we are returning the promise that is why I caught this issue let's return new promise and resolve return resolve this object I just created the fake promise to pass this test oh I have written the profile in the mutation let's change it to query restart the application now we're going to send the request it's still running now we're going to access the profile I caught the profile but only authenticated user can access this profile so we need to apply the O guard how can you do it let's create a new guard I'm going to copy that guard and create a new guard and I'm going to say gql oards here instead of JWT I can say graph o card and now we need to do a little bit logic we need to use the can activate function because in graph ql we need to get the execution context and we need handle request it is going to return a user and you can import authentication error when you look when you look at app module you will see this request I'm just mapping the request from req request here I got the request from the context here you can see that and I call the super Constructor by calling this execution context host because in graphel you need to get the request object from the context when you have if you have worked with graphql before each resolver will have four argument here you will have for argument parent I think root context value and info you can get the documentation from Apollo server resolver here you can see each resolver has four arguments parent ARS context value and info ARS you can see ARs and I'm going to log everything parent console. log ARS console. log context value and we also need to log the info let's see what is inside this this stuff but make sure you apply the guard use guards I can say graphql or guard now this route this resolver is protected it is secure now don't worry I'll teach you everything what is going on here let's send the request here you can see the log console there are a lot of stuff here parent is undefined there is no parent for this query ARS is an object but is but there is nothing inside the ARs there's a context value this is there is the request object and inside the request object you can find your user here is the user I found the user this is the this is the user this is the this object is current logged in user if you look at the jwd passport strategy here we are saving user ID and the email that's why I got the user ID and email what I can say I can only return context value do request. user I don't need to use the promise here it's just returning a simple profile I'm going to send the request this time I got the original user ID and the email let's sign up up a new user I'm going to create a new user Linda let's save the email now I got the user we have successfully sign up let's log in I got the access token now I can use this access token here I want to access the profile of this route or user wants to see this his profile I got this user now let's debug the application I'm going to put couple of break points here what is going on here let's look at I have already set up the VS code folder inside you have launch. Json file if you don't know how to debug the application let me teach you I've already taught you there is a script in the package. s file for the debug the application you can say npm start please start the project in debug mode my application is running in the debug mode now I can start the debugging by pressing on this attach button I've put couple of break points here now it has started I can debug my applic a I can also put breako here or here now we're going to send the request it has stopped at this o card and first of all it is going to run the can activate function we are using getting the graphql context by calling the create and here I got the context object and inside the context you can see we have the Handler function we have the ARs ARS property the first one is object and we have a request we have this request and we have field name which is graphql field which is profile you you can see the field noes this is how graph run under the H this is my string or the query graph request and here is the name something like that profile which is profile let's step over the code you will see the context inside the context we have OD context type graphql now I'm extracting the request object by calling the get context so I got the request inside the request you can see that this is the request we have this endpoint SLG graph ql this is the body we have the query and we have the variables let's jump to the next break point there is no error and there is a user you can see that and it is going to return the user now you can access the user inside the context parent is null which is undefined we don't have anything in the ARs now you have the context value you can also do debugging here context value dot request. user you can see I got the user and we have the info info is related to information related to query if you need to access the path parent type field name something like that schema then you can use the info validation error we have directives include skip deicated query type graphical object type we have the fields login profile all this information related to graphql schema and the query inside the info object now we are going to just return the current logged in user that's how the authentication Works under the hood in graphql if you need to implement realtime application you have to build a realtime functionality like chat application or notification type application then you use graphql subscription if you have worked with API rest apis we used websocket and socket iio for realtime application but we are building graph apis if you need realtime functionality then you need graphql subscription I'm going to build or Implement graphql subscriptions with nestjs Pro project first of all you have to install dependency graphql subscriptions and then we will install the subscription Handler just like query and mutation you need to define a new type subscription I have created this song created field it means when a new song is published to Spotify application this Spotify application will send the notification to all users we want to implement this feature when you define the type subscription we defined it here you have to write the resolver to resolve this field we need a pops up module from graphql subscriptions the package we have installed earlier here it is going to listen for song created event this resolver is listen for song created event here we are resolving this field song created when you run the application you should go to the Local Host colon 3000 /g graphql I'm going to run the subscription song created we have ID title I have started the subscription you will see the subscription is listening it's in the listening mode our next step is to publish this event when we will publish the event you have to send the payload which is a new song and I have created a new song Here we are publishing an event here it is going to now the subscription is already running here you can see and now it can receive it has received a new song if you want implement this subscription you can do it otherwise you can follow me I'm going to implement it you have to install package graphql subscription and we have to install the Handler in the app module install subscription Handler let's define a new type subscription in the song graphql I'm going to Define It Here song created it is going to return a new song now we need to resolve it resolve the song created field inside the song resolver we need to import psup at the top of our resolver you can import it from graphql subscriptions package now we're going to resolve this subscription song created I can do it here at the bottom we need to get subscription from nestjs graphql package let's try to import manually from cql subscriptions we need pups up let me run the application and then I will be able to start the subscription in the listening mode the pups sub Asing iterator we are telling to pups sub module or the ppup module is saying I'm listening for the song created event with this label this is an event I'm listening for an event with this label song created my application is running now let's run the subscription when you check the docs you will see subscription with song created I'm going to start the subscription song created when a new song will be published it is going to give me this record the song object now it is in the listening mode when we will create a new song it means when artist in real world Spotify application has published a new song Spotify application will send the notification of this song to all users new song I can say new song I need to get ID and the title a new song has created but I cannot see anything here because we did not publish the event when we will create when we will be creating a new song Here we have to publish this event this one song creat event so you can do it as well I'm going to copy my code and let's do it here this is how you can sent message to the event by using the song created label and we have provided the payload make sure you use the song created Property name otherwise it will not not work let's create a new song I have created a new song and it is saying I cannot could not connect to websocket endpoint please check if the endpoint URL is correct now it's in the listening mode mod created a new song now I have got a new song because we are publishing a new song and it has received it here let's say I can say new the name of the song you can choose any name I have created a new song or artist has published a new song at Spotify web application now the Spotify application has has sent the notification to all users who are subscribing to song created event that's it the concept of subscription in this module you're going to learn how to test graph apis we have already tested our rest apis we're going to use the same logic to test graphql apis we're going to do Mocking the same way just we did in the previous module when you see song resolver dopc file you will see this default code when you run the test by using this command npm run test you will get this error hey you are using a song resolver but your song resolver is dependent on song service you have to import it but we are doing unit testing so when you are doing unit testing you have to test individual parts of your code you have to test individual functions if this function is depend dependent on some other functions or some other dependency or some other classes or some other services you will create a Moog implementation of the dependency I've already taught you the Moog implementation when we will when we will be testing song controller this is how you will create the mo implementation of song service you we will have have these methods inside the song service in get song create song we are just creating the mo implementation I just copied this code from the song Ser song controller song controller spec file and I have updated the create song dto to create song input and update song dto to update song input and then you will test your functions if you want to test your get fet song Get song function inside the song resolver you can do that I'm applying the await expression on get song and I got the song here I'm doing expectation checking asserting or expecting value it will pass this is how you will test create song create song will be passed update song and the delete song Let's execute it or you want to execute by yourself I want you to do it let's select the song resolver it's going to run the song resolver dopc file you can see the error hey your resolver is dependent on the song service but you did not import the song service let's fix it by mocking the service I'm going to copy the same code and paste paste it here we don't have song service let's import it it's not giving me the suggestion I have to import manually I got the song service we also need to get the create song input and update song input I think it will not get this path Source do/ graphql let's add the complete path you can see our test has passed now now we're going to write the test unit test for a song's query it should fetch a song first of all I need to apply a weight expression on get songs it is going to give me this song because we are using our Mo implementation inside the get songs it is going to return this object or this array with a promise here we are just resolving it unable to fetch songs I got the error let me check my song resolver what is inside the song resolver I think I'm throwing the error that's why I got this error let's comment this code and I would like to return this song service with get songs array it is going to give me the array of the songs we are just using this get song method but we are using this implementation this one it will call the get songs but it is it will use our own implementation this one this is how you can fix the bugs with the help of unit testing our test has passed now we need to test a single song query we have created this song actually we need to yeah we need to test this one we need to create test create new song resolver we're just creating a new song and we are expecting it because create song will give me the ID and whatever we passed here the object it is going to return the same object here the test has passed now we need to test update and delete it is giving me the error update song a unique ID we are not expecting the ID in the update song there is an issue I think it is going to give me the ID let's look at the update song resolver song resolver let's look at the update song update song I think I have to change the order first I need to get the ID I need to place the ID and then I need to get the update song input you have to rearrange the order now it should work let me look at the song service ID it's giving you are not using the update song tto title but let's restart the application the error is gone now everything is fine our update test has passed and our delet delete the song test has also passed it is returning the affected that's why I use the affected here in the next video I'll teach you how to do end to end testing graphql apis this lesson I'm going to teach you how to do end to endend testing with graphql apis in the previous lecture we tested unit tested we tested the individual function of resolver now we're going to do integration or end to endend testing we're going to test exactly the API by sending the HTTP request or queries from the HTTP module this is how you will test the songs query and it is going to give me the result I'm using the request request package to send the HTTP request if you are working with graphql there is only single endpoint which is/ graphql it will be same for each query and mutation now I'm trying to fetch all the songs and I got all the songs this is how you will test the end to end testing I already taught you how to set up the end to end testing file when we were building when we were testing the rest API in the previous previous module so before each we're going to create testing module this is a same before all we're going to create new database I have the test database it will drop after completed all the test and after each we're going to delete everything after each test we're going to delete everything from the songs table that's why I'm using the songs Repository do clear method and after all we're going to stop the application we're going to use this method to test it's a helper function to perform our testing nothing more it's just creating a new song and this is how you can test a root end point it means our testing is working fine let's implement it there is no script for end to end testing for the we have an end to end test but I'm looking for a watch mode testing that's why I'm going to add a new script it will run end to endend testing in the watch mode let me run the end to end test in the watch mode it should be e to e e to e right now we have only a single file which is AB do E2 e-pack dojon if you run this file let's say app it is going to run this file I'm going to copy this source code and let's create a new file inside the test folder we will use this test folder for in to end testing let's define a new file song SL do E2 e-. I have copied the source code this is the default code we need to add a type orm setting before all the test we need to create a new database let's run it here we need to import couple of modules we need a song module and song entity let's get it type Ork module we also need to import type or module actually I'm going to copy everything and paste it here now we have before all we also need let's define it should be song resolver end to end test we need after all and after each after each test you need to clear the songs table and after all the test you have to close the application I'm also going to use this helper function I already taught you these Basics when we were building when we were testing the rest apis that's it our setup is complete now let's run the test this time I would like to run songs file let's try to run the song file song. E2 e-pack our test has passed now and you can see this test is running fine now now so we have successfully done the setup now it's time to test the query we need to create the song first because there is no record in our database table which is songs there is an empty here there is no record so I'm just trying to write the query to fetch all the songs I created the query data object I'm providing the query and I'm sending the query in the HTTP request when you test the API graphql API you will get the data or the response in data object and we have the songs I'm just expecting the songs array uh uh let me run the application in development so you will understand it more deeply application is running now let's try to write the query to fetch all the songs if you write the query or you can do without without query I'm going to write query query and I would like to fetch all the songs ID and the title so you got the result in the data object and we have the songs array one more thing if you write the name of the query you can also do that if you have experience in graphql then you will know what I am doing you I'm just I just gave the name of the query get songs you can also do that it will work fine there is no issue now we're going to test a single song query this time first step I created this song and I created the query object now we need the variable this is how you can Define the variable in graphql so I'm providing the variable ID here you can exactly query in your graphql playground let's say it this is a new tab I can give you the name of the query get song let me copy that get song now I def I created the get song query and I'm expecting the ID as a variable here I'm providing the variable ID this is how you will set the query variable this is a another way to fetch the get song query I already taught you this method it will work fine you got to provide the ID and here you can expect the name it will work fine but this is another alternative way of doing this thing if you have an ID you can provide the ID here ID we don't have any record that's why I got the error now we going to test it you can see our test has passed now because first we are creating the song then I'm providing the ID variable from the new song object you don't need to change anything here you can also do expectation for assertion check for the status code here instead of calling this one that's why I I'm expecting the 200 status code and it is going to give give me the response data and the song and I'm checking on the based on new song both are same now our next step is to test the create song mutation it is the same way you define the mutation I give the name create song mutation instead of ID I'm expecting the create song input we have created the variable and I'm getting the create song input we have title and here you can provide the values for your variables if you want you can do the exact same thing from your graphql playground let's say I can say I'm going to create a new song I just past it pasted the mutation if you run there is no query variable for create song input let's define it you have to provide the title I can say lover song you can see the lover song now I can provide the ID here let's test it here I provided the ID so I got the song object there is a data object and we have a create song object that's why I used create song Here create sing do title should be animals our test has passed now we need to run update mutation similarly just like for just like with create mutation it is expecting to arguments ID and the update song input and we are providing the ID in the variables and update song input here here it is going to return the affected with integer now we're going to copy this delete mutation delete is expecting only the ID and it is going to return the affected I defined the delete song mutation and here I'm expecting the value which is one our test have has P tests have passed query and we also need to test delete mutation delete mutation test has passed F this is how you will do end to end testing in graphql in this lesson I'm going to teach you the concept of caching Apollo server provides caching on the server site you can implement it caching is a process of or method of storing copies of file or data in a temporary storage location or cash to be accessed quickly like you want to store the data temporarily in some type of in memory built-in memory you can store the data Maybe for 30 seconds or 60 seconds or a 1 minute it's called caching what is server side caching you want to store let's say you want to fetching the query results you have a query and user is fetching the query constantly after every 10 seconds after every 20 seconds or after every 10 seconds in that case you need caching you don't want to send the request backend server to DB server again and again so it will increase the massive traffic load you are thinking why do why need why do we need caching if user is fetching the query after 3 seconds again and again you did not implement the caching your application will send the request to the backend server DB server and it will and it will fetch the data from that server again and again it will decrease the performance so the help of caching you can improve the performance of your application you can avoid unnecessary request to server because the data will be fetched from the cache immediately you can reduce the bandwidth which will be benefit to user you can reduce the massive DB loads with the help of caching you can handle massive Network traffic request yeah you can decrease the service calls so that was the basic fundamental concept of caching now we're going to implement the caching in in nests project nests already using Apollo service AP poo server Apollo package so we're going to install the package uh install this caching module Apollo server plug-in response cache this plug-in helps optimize the performance of graphql queries by caching the responses this this plugin will help us to Cache the response and serving the data from the cache instead of executing the same query repeatedly our next step will be register the caching plugins when you install this plugin you can register it as a plugins array I have set the default maximum age which is 5 Seconds I'm saying hey Apollo you can keep the data in cash for 5 seconds after 5 Seconds you have to refresh the cache you have to refresh the data and then you need to create a directive cash controls SC private or public you want to fetch the data publicly or you want to fetch save the data privately private represents a cash control scope where the response should be cached privately if you want to fetch the authenticated user something like that then then you need to set the private represent a cache control scope where the response can be cached publicly this directive will have max age scope and inherit max age and you can apply cache control directive on field definition you can apply on a fing field like title field in a song type you can apply on object interface and Union the max age is an optional argument of type in that represents the maximum age of the cach control in seconds how long the response can be considered a fresh and cachable you can read this documentation of maxh I've written down for you private and public scope this will be used for parent let's suppose your query is dependent on parent query then you need to use this one you can also set the cach control set cach hint in the resolver by using this line our next step will be apply the cache control directive I applying it for titled field inside the song type cache control maximum age for 30 seconds I'm saying to Apollo hey Apollo you can keep the title field record for 30 seconds in a cache if user is fetching this title field constantly after 20 seconds or after 10 seconds then it will fetch from the cash if user needs to fetch record after a minute or after a 2 minute it will fetch the data from the DB server but it depends on you on your case on your use case but 30 60 and 40 are the recommended values on the based on Apollo documentation Apollo server uses inmemory cache by default we are we are going to use inmemory cache but you can also configure different backend like redis or M cach you can also apply cash control directive on a complete type let's say if you have a scenario where you need to fetch all of the fields from a specific type then you can add here cache control directive maximum age to 40 seconds I just give you the basics Basics when you implement in real world scenario in real world large application you will know your use case better now it's time to implement it or you can implement it by your own let's install the plug-in first plug-in have installed let's import it in the app module now we're going to register the plug-in into plug array when you are creating graphql module you can register it here so our third step is to creating a cache control directive I can do it here it will have max age scope inherit inherit max age private if you want to dig into more deeper you can look at from the Apollo server documentation when you Google Apollo server caching this is the document you got to read if you want to dig into deeper what is Max age what is cach control scope you can read this document this is the implementation of caching in AP poo server if you want to do ready setup you can also do that we have created the cache control directive now I want to apply the cache control directive on our field right now I have only one single Field title I'm saying I'm assuming that my title field is going to be feted after 10 seconds I have a query in that use case like client is asking title field again and again let's try to test it first my application server has started now I can say I want to access the query of the songs I want to fetch the title you can see it's working fine now let's fetch the title again now it is accessing the title field from the inmemory cache one last thing you can also apply cache control directive on a type here I want to say I have only single type that's why I want to use it for only demo purpose in real world application you will have a different use case restart the application my application is running now I'm going to access this song FEI songs it's still working fine if I try to access the song we need to provide the ID let's fetch the ID I'm going to copy the ID and let me paste it here now I would like to access the ID and the title let's access the title only or the ID now the data is is going to be cached I can access it easily it's working fine in this lesson I'm going to teach you the concept of data loader why do we need data loer we have this schema I've already found example project regarding data loader we have a user and we have a post there is a relationship between user and the post when you send the graphql request to fetch all the post and you also want to the owner of this post who has created this post under the hood graphql your application will send a a different different a new data request to the database a new request to the database to fetch a user for each post this will decrease the performance of your application because you're going to do lot of database request here your output will look like that if I will show you here let me show you with the help of example I'm going to send the request it is going to take a 3 seconds because I have set this delay for the 3 second we have how many post we have we have three post you can look at the schema or our database I don't I'm not using any database here so here is the data we have a three post inside the post we have a user ID when you look at the user service we have all of these users every time let's say I log the message fetching data from DB let's example you can say that getting user ID 1 fetching the user ID one this is the you can imagine this is the database request every time it is going to fetch the post for each user against post it has to fetch the record from the database you can imagine if you want to load 50 post and you have to send the API or backend DB request for each user separately so what data loader will do data loader will batch all of the users it's going to wait and say I can send you request here what data loader will do it will say I will get all of the IDS of the users like one 2 3 and then I will fetch all of the users for all post and then if you need any post if you need any user against each post you will fetch from the cash or from the data loader cash data loader maintains cash also did you get the point let's say I'm going to add I have four users inside the post service I'm going to add post for title post for something and user ID which is for this one application is running now I'm going to send the request to fetch all the post now I got the for post and it has sent the DB request to fetch a single user what we can do we can say I want to fetch if we are using data loader please fetch all the users it's batching all the users from the DB and maintains a cache and next time our application will fetch the user from this cache I have already implemented the data loader in this project actually I found the source code on the internet to explain the data loader it's a simple source code so I thought I should teach it with the help of this source code inside the post resolver here they are resolving the created by field created by and it is going to return the user here instead of loading the user from the database let's user service will send the DB request so I'm going to comment and now you will see the magic instead of loading the user from the DB I would like to fetch the user from data loader now we're going to send the request you can see that getting the users with ID 1 2 and 4 it has bashed all the users and created the user map to send the ID's record to data loader and here is the result so let me explain what this source code is doing if you check the app module here we are providing the loader I created the create user loader and they are injecting the user service inside the user service inside the create user loader I'm passing the user service to work with data loader you only need a single package which is data loader this one you have to install only the data loader here you will have a user loader what this loader will do it is it's nothing more it's just a function takes a user service so I created the instance of a data loader the ID will ID would be number and another type which is the object should be the user this when you create the data loader you have to provide it is going to give me the IDS all of the IDS and here I can fetch all of the users against IDs here I did the users map you you saw the users map here 1 2 3 because data loader Works in this way you have to provide the results in this way like I got 1 2 4 then I did the map to fetch all the records ID 1 2 and 4 we created the user loader I have attached inside the context object remember graph resolver can have four arguments in for context and parent we have user loader here to fetch all the users against a post here this one inside the post resolver I'm resolving the created by field I got the user loader from the context here you need to load the user from the user loader I got the parent I parent record from the post which is the post so I got the user ID which we saved here we have one more thing we have used a schema based approach to build graphql apis but I also wanted to show you another way to build graphql API which is code first approach this code first approach will generate the schema. graphql file automatically it depends on you but I like the most schema based approach but you can use both of them it depends on your use case this is how you will Define the graph qu object type but we have worked with this schema based approach let's say you want to create this graphel type which is posted with the help of code based approach you will say this is the graph object type you can get it from nestjs graphql package and this is the field you can say this one this is the field and you can say title field and we have the body field and we have the user ID I'm not I'm not saving into the graphql datab graphql graphql type that's why I keep the user ID for entity based to build a relationship with them so created by this is the relationship between a user here you can see that created by the return type should not be null that's why I they have used the user this is this represents the return type what your field will return so it's the type of this created by it should return a user user type similarly you can look at the user entity object type this is how you will Define here this is graphql type and my user id the type should be number that should be int that's why it's a nonn knowable field and it should return or the type of this ID should be int and we have a field which is graphical type so this code will be converted into this schema type and how can you resolve the resolver when you look at the post resolver this is the resolver and I say this is the post resolver that's why I provided the post entity now we have the post resolver the query tag so here you want to say what resolver this will do in we are in the post we are here so this query will return all the post and the name of the query should be post I'm resolving this query so I'm fetching the post similarly if you want to resolve the created by here this one you have to provide the resolve field is all field there is a field inside the post Ty which is created by and it should return a user so this is the return type this is how you will mention the return type it should give the user and I got the parent and the context this is a uh nextjs has documentation on graphql you can learn more about a code based approach if you like the code based approach you can learn more about from the documentation this is the code first approach the object types you can read the documentation if you are not getting what I'm talking about you can just read this text it will help you to understand the code very easily so this is how a field and type should be post array I want you to check this documentation one more package I want to share you have graph nestjs graphql tools if you want to use the code based approach and let's say you are using post or type orm this is the package if you want to work with database and and you want to use loader they have already built a data loader here if you like this package you can implement it it's simple you need to provide resolver user object type user resolver here it will have graphql loader you only need to just provide The Decorator graphql loader and it is going to implement the loading stuff here if you like it you can implement it there is a this is how you will Implement one to many many to one and this is the usage I just want to show you you can do if you want to use database and data loader you can Implement by using this package this package also have more features on pagination sorting and field extraction Etc if you want to fetch data from external rest API you can do that we're using Apollo server AP poo server provides a package to fetch data from external rest API a poloo data source rest I have attached a started project I have already in I have already have this package in package.json file you have to install it Apollo data source rest you have to do npm install to install all the dependencies this is a class you have to extend it we're going to do we're going to fetch todos from this Json placeholder API it's a fake API with real data let's say I want to send to-dos request it is going to give me all of the to-dos I want to fetch this rest API now this is how you will implement it you will have this schema you will create the schema to do ID user ID title completed with Boolean I'm using the same property I defined a graphql type and then we have a query query to fetch all the to-dos I have a to-do module inside to-do service to-do resolver now to-do service is is going to f fetch the data from external rest API instead of data database inside the to- do service here you have to extend the rest data source it will it will ask the call the super Constructor this is the base URL I'm going to call this.get to fetch all the to-dos you can use this method I I can get the data source object from the context here you got call data sources. too api. getet too I'm talking about this too API like this one so another important thing this is how you will add a data sources inside the context it's an asynchronous so I provided the data sources if you want to implement you can go ahead and do it and let me do that for you I have I have to do docraft in my started kit project now let's extend data source rest rest data source let's have the Constructor I'm going to call the super Constructor now let's set the base URL I can get the base URL from here I don't need to provide todos this should be the base URL now let's define a function to get to-dos and it is going to return the array of to-dos I can get the type from the source. graphql file the typescript file I've generated the typing by executing this command npm run generat typing so let's call this dot here disor get and provide the path to do is everything right I can check the path which is to do so we created the data source and now we have to add this data source into to do resolver we got to call this actually we need to add in the context I'm going to create the data sources function it's going to return a to-do API let's create import to-do service it's going to return the object and the function is going to return the object now I can add in the context here it looks good so you can use the context object here inside the to-do resolver to do resolver let me get the context data sources and I'm going to call all this method data source is a function there is a to-do API object and we have get too function let's start the project project is already Runing on 3,000 let me stop the project let's run it again my project is running I'm going to send the request I got all the 200 toos Unfortunately they don't have pagination otherwise I can implement the pagination but you got the concept how to implement the rest data source if you want to do more Advanced Thing by using the rest data source package there is also a caching functionality you can override the method I want you to check the documentation if you want to implement the rest data source there is also a data loader you can also use the data loader with rest data source I want you to check this documentation it also provide to fetch duplicate records you can read the documentation to understand how to use the cache stuff like that in this module we're going to use Prisma orm and we're going to build rest apis Prisma is an orm in nodejs or JavaScript when you look at the documentation it's they are saying it's a Next Generation orm for nodejs and typescript project it's similar to type orm but it is faster it's an efficient they are maintaining this project regularly so you can look at the use cases and customer stories when when do you need Prisma you can read the customer stories and use cases so in this video I'm going to teach you how to set a Prisma in next nestjs project you can also get the Prisma documentation from nestjs package from nestjs package inside the njs documentation you will find a Prisma folder you will see the Prisma section here is a Prisma orm documentation the first step we need to install the Prisma I have provided the started kit code for you you can go to the starter branch and run nbm install to install all the dependencies this is just a basic Nest CH project I don't have anything here just Basics basic setting for nest CH project it is taking some time to install the dependencies meanwhile I'm going to create a new database for Prisma because we're going to use postp with Prisma I'm going to create a new database Prisma API something like that you can choose any name all the packages have installed now we need to install a Prisma as a dep dependency Prisma left dependency has installed now we need to initialize the Prisma project I can use npx init Prisma in it it will set up the Prisma in our project you will see schema. Prisma file inside the Prisma folder here I'm telling I'm going to use Prisma client Library this is my post database provider this is my database URL they have also added a created EnV file here we have postp database URL make sure you have ADD theb in the git ignore I think I've already added it yes no I cannot see that let's add EnV I don't want to put push my EnV to GitHub they have already installed post so I'm going to work with post this is how you will set a Prisma in your project in your nestjs project in the previous video we have set up our Prisma application now we're going to create our first model I'm going to create the song model the type should be int and by default this should be int by default I'm going to set it to Auto increment and this is the ID let's add another property this time the type should be string but we did not set database URL for the post I'm going to create a new database let's create a new DB Nest Prisma app or Nest prisma-p my username or owner is postgress now we need to replace the owner here postgress and your password and the name of your database and schema should be public I'm going to run the application my application is running fine let's try to check the tables inside the schema I'm going to refresh and inside the tables I cannot see any table because we did not migrate the database let's create our first migration migrate F Prisma migr F and the name of your migration I can say in it this is my first migration I think I did not provide the right command Prisma migr DB or Dev yeah npx PR migrate Dev Das Das name of your migration this is my first migration that's why I chose the init name but you can choose anything here Local Host provided DB credentials are not valid post SC there was an issue with double s now a new migrations folder has created inside the folder we have in it migration file we have song table this is the migration log let's try to check in our database I'm going to refresh my tables and you can see the song table in our database but we also have two columns ID and title in the previous video we have created our first model and we ran migrations but Prisma also provides a Prisma client to perform cred operation this Prisma client will generate the correct apis correct functions for song model you will have prism client. creat song prism client. find song all of these methods in the prisman client Library here we are using the prisman client but we have to install this package Prisma client and P install at Prisma client this package will provide scrud operations for all of your models this Prisma client will interact directly to the database so we created the Prisma Cent installed the Prisma client now we need a service inside the source directory and I call it Prisma dos service. s it's injectable service exort class Prisma service and I'm going to extend the Prisma client Prisma client here we also need to implement on module in it because we have to set up the Prisma client when our application is running I can call it on module in it on module in it this do connect this connect method will connect our uh connect this Prisma client to our database I have I have not imported injectable decorator let me get it that's all you need to connect Prisma client to our database so we will not use Prisma client we will use Prisma service to interact with database we're going to talk about how to create cred operations we have created a song model here I want to create the correct end points one more thing I did not talk about or I did not teach there is a resource generator this CLI command will generate the correct API endpoints controller module service dto object something like that if you need to scaold your application you can use this command resource it can also works with work with graphql code first approach schema first approach or you can create a micro service or you can create the web socket but I chose the rest API because I would like to build the rest API yes I also want to generate correct entry end points we have the songs model we have d object entities so on controller service we have all of these method inside the service we have created a Prisma service now I'm going to use a Prisma service here to interact with database can call it Prisma Prisma service it is going to give me the error that's why I use this path first of all let's create the create method return this do Prisma Dot Song you can see we have a song object there is a create method and you have to provide the data here you have to provide create song dto one more thing I want to talk about you can use the types from Prisma client Prisma client already generated couple of typescript typing let's say first I need to import Prisma from Prisma client you will find book create input the type in this type you will have title field we also need to update inside the song controller we got to get Prisma client and you will have book DOT book create input my vs code is not giving me the hint or suggestion now we're going to run the application it is going to give me a couple of Errors maybe oh it's not a book it should be a song because I'm accessing the song model I'm using the book song song. input not a book song create input I did not import Prisma service inside the song module because we have to import it that's why you have to register it as a provider Prisma service so I can get the Prisma service my application is running fine now now we're going to test it with the help of fresh client let's create a new file I can say HTTP client. HTTP create song post HTTP HTTP Local Host colum 3000 SL songs what is the name of the API I can check it from the controller we have the songs content type application Json let's provide the title follow me you can see a new song has created successfully now we're going to write the function to fetch all the song This start Prisma I'm going to reload my window it is not giving me suggestions Prisma Dot Song dot find many there is a method find many let's try to get all the songs you can see I have a single song now we have to implement the find by ID this do Prisma do song now it is giving me suggestion find unique and we have to provide the ID where clause and you have to provide the ID let's try to fetch the song on the based on ID fetch song by ID so I got the song by ID if I provide the invalid ID I should get the empty record I'm getting issues here I think I need to generate the typing you can call this method npx Prisma generate it is going to generate the typing inside the node node modules and Prisma inside the Prisma you will get the typing I got this from documentation this typing will be stored inside the node modules inside the Prisma and the client directory generated Prisma client reload the window now the error should be gone now I have to update it it's a song create input we also need to update in the controller we have the song controller here it should be Prisma Prisma SL song create input I have to get this ke Prisma client now the error should be gone now it looks good so I can create a new song and I can fetch all the songs that looks good in this lesson I'm going to teach you how to create update endpoint actually we have already created the update endpoint you will see the patch endpoint Point inside the song controller there is also a method inside the song service there's an update method all I need to do is to use a Prisma service inside the song service we have have to use the update method from the Prisma and there is an update method inside the song update here you got to provide we clause and the data where and data we have to fix a little bit changing here I'm getting I'm going to get we clause and I can get the type for for Vi song We unique input similarly I would like to change the type here Prisma do song update input you can remove the V because both the key and the value are same so I can use a single V we also need to update the type in controller file let me update the type here here I would like to send the object instead of single parameter which is ID here I can change the type Prisma do song update input we also need to update the find one a little bit I would like to get the songw unique input and let me get the songw unique input and I'm going to provide song wear unique input we also need to update controller for the find one let me send the ID in the object because I'm receiving the object here here if you want to look at all of these types where these types have stored when you go to the node modules you will find there is a package Prisma do Prisma client you will have all of your types in index. D.S file so I can get song whereare input you can see we have a song We input can say type here here we have a song We input you can have ID and the title here we have the song where unique input you have you can have ID and or note in the title now we have to test it run run the application cannot find primsa let me fix that there is an issue Prisma now my code looks good I'm going to send the update request from my rest client from my HTTP client the song by ID we have to send the patch request instead of put and going to update this song with id2 copy the content type dancing feet let's see a song has updated successfully if I fetch the song on the based on ID it looks good we have dancing feed let's create another song I have created another song I would like to update the title my title has updated so you can fetch all of the songs it looks good we have implemented the update operation now now we have to implement delete operation I'm going to use the same strategy to delete let me get the ver clause in the input there is a method in the Prisma Prisma do song. delete it is going to accept the V Clause now I have to get it in the controller we need to pass that inside the song controller here I have to provide the ID inside the object ID let's try to test it with the help of HTTP client I can say delete song by ID I'm going to provide the ID instead of patch we need to use the delete operation you can see this song has deleted I can verify by fetching all of the songs you can see we have only only two songs right now now we're going to build relationship between models Prisma also provides one to one relation one to many relation and many to one relation and also have many to many relation I'm going to add a new model artist let's add Fields inside the artist I will have the ID and the name of the artist now each song an artist I'm going to add one to M relationship between artist and songs each artist can publish many songs I saved the application you can see it has automatically added a relation let's rename a small a to a capital A to small a here you can see there is a reference here artist and fields which is artist ID and the reference with the ID now we have to run the migrations npm run migrations oh I have to run npx Prisma migrate Dev the name of the migration which is ADD artist it has also generated the Prisma client queries or Prisma client types when you see the migrations you will have the create table cury it is going to create the artist table it has also added a relationship between song relationship between songs model let me try to check the types you can check it from Prisma client index. D dots do I have the artist type yes let me find artist create input yep it has generated the types for me now I'm going to generate a new resource for artist an artist resource has created I don't need entities I'm going to delete them here I also don't need entities in this song because we are defining our models in the schema. Prisma file let's create the artist we have to open the r service and here we need to inject the artist the Prisma service I can get it from the song service which we have to import these two dependency Prisma service and the Prisma client I'm going to copy the Constructor here we have to find the Prisma create input command F to to find artist create input yes I would like to use that type I can get it from the Prisma client Artist Artist create input that's it now I can use Prisma do artist do create here we have to provide the data object and inside the data I can provide create artist dto one more thing you need to add Prisma service in the artist module we have to register it Prisma service let me import Prisma service and here I need to add Prisma service we also need to adjust a type in the controller for artist controller we have to update our type I have to use the same type Prisma dot artist create we have to import a Prisma otherwise it will give you the error I'm not going to use the create artist dto so the artist create input can take the name of the artist if you want to inject the multiple songs you can also do that you can look up the documentation of Prisma how can you insert multiple records if you want to do in this way you can also do that artist unchecked create input but I'm going to use this one simple one npm R start Dev my application is running fine now let me open the HTT HTTP client let's send the request to create new artist create Artist Artist here I can provide the name of the artist can say Martin Garrick a new record has created successfully the artist record has saved let's add a new artist V another artist has created we have made one too many relationship between artist and songs when you add a new song you can add a relationship for the artist here when you check the schema. Prisma file you will have the artist ID in the song model that's why we need this is how you can build a relationship between song and the artist so what I can do inside the song service we have to expect the song actually author ID I can find that song create input so I have this song create input type I also have song unchecked create input did you notice the difference between these two types here we have the artist ID I can add the artist ID if you want to insert a complete artist while creating a new song you can also do that you can look up the documentation and here you can you can do in this way you can provide the array if you want to do that if you want to insert a single record you can also do that but I just want to show you the way to add record so I'm going to use this type instead of simple song create input now you also need to provide the author ID in the in the request parameter here I'm creating a new song here let's provide the author ID which is one I'm going to create a new song let's say Animals by Martin gck I got an issue not an author ID it's an artist ID why I'm saying the author ID I got the record with this author ID if you want to query the artist in the response let's say I'm going to I'm going to fetch all these songs but here we have artist ID null here we have the artist ID one if you want to populate the record of the artist you you can do that in the find menu and here you can say include artist to true that's it let's fetch all the songs here the artist ID is null artist is null here you can see the artist ID one and we have a complete artist record that's how you do population we have used this include syntax you can also use the connect object if you want to make the connection or update the reference ID you can use the connect now we're going to implement one to one relationship between two models we're going to have a user model here we have a one to one relationship between user and profile each user will have one unique profile in the profile we have photo we have the phone number of the client of the user this is how you will make a one toone relationship user and a relation and this makes each profile will have a unique ID of a user table then we will generate Prisma migrations then we will generate a new user with the help of nest generat resource a user we're going to use cred AP endpoints and finally we're going to save a user on the based on profile like when we are when we are saving a user I also want to save the profile this is how you can do that profile and a create object and the attributes of profile table it will automatically made a relationship between user and a profile and finally I want to fetch all the user with the profile if you want to implement it you can do it but let me show you how can I implement it I'm going to copy the model here here here inside the schema let's add two new models I've added two new models let's run the migration npx Prisma migrate Dev the name of the migration one to1 relation it has run the migrations and now it has also generated the types inside the Prisma client I can double check that from the Prisma here you have all of your user types user and profile when you search the profile here we have profile stuff our next step is to generate a resource Nest generate resource users select rest API end points getri of the entities and I need to inject Prisma service inside the module inside the users module I have to inject the Prisma service here Prisma service inside the user service we need to inject Prisma service dependency I can get that from the song service we need the Prisma service and I'm going to copy this one as a Constructor so we have to call the create method I'm going to copy the exact create method and provide it here that's it this time I'm going to use the create user dto I have not defined the properties in the create user user dto if you want to add the validation you can use the class validator I taught you earlier in the previous modules we will have photo the URL of the photo should be string and phone number the type should be string now we're going to I'm going to copy find all method and I'm going to use this profile I want to fetch the profile with each user now let's try to test it run the application this create object is used to create an nested object a relation relation object let's create a new user users provide the name of the user jendo and we have to provide the photo URL some api. com/ phos 1. J APG and you need to provide the phone number let me create a new user a user has created successfully let's try to find all the users VCH users here you can see that I can see the user and we have the profile object inside the user you will also see a relationship with user ID one which is one that's how you implement one to one relation in this lesson you're going to learn how to implement many to many relationship between models I have this use case one blog post can belong to many categories and many categories can belong to a single block post so there is a many to many relationship when you implement many to many relationship you need a third model in the third model you store the foreign key of your first model and the foreign key or prime for foreign key as the primary key the foreign constraint here it's a it's a foreign key of category table and in Prisma you define the primary key by combination of post ID and the category ID this is how you will make uh many to many relationship now the categories instead of categories array you will use the categories on post array the same stuff here instead of using post array here you will use the categories on post array and then you we will generate migrations we will generate migrations and it will also generate the Prisma client types and then we will generate the resource post we will create the post by using this input type post create input and I also have to update the type in the controller and this is how you will send the request to create a new post here the title of the post one to many relation this this is the Prisma post and it it can have two categories here you can say I I'm going to create a new category this post can also belong to Prisma category this post can also belong to nestjs category that is why I created two categories you can see that category number one and this is category number two here I here we have the array of the categories similarly you can do the same thing if you don't want to create a new post you can connect with existing post I'm going to teach you transaction let's say I'm going to write blog post on transactions in Prisma and here this post also belong to nestjs category and Prisma category that's why I'm I'm connecting to category number one and the category number two and finally you can also do a relation queries with the help of this type post where uni input also have to update in the controller this is how you can send the request categories this is a we Clause category and the name you can check all of different type of queries in the documentation let's try to implement it first if you want you can Implement by yourself many to many relation I'm going to create a post model and my next model model is category it will have name and the ID and my third model is categories on post I'm going to save now you can see that these two properties are inside the categories on post I would like to store the date and I want to store who has created this let's run the migration it has also generated a Prisma client types you can check it in the node modules at Prisma / client our next step step is to generate the post resource we're going to perform some cred operations please select the rest API yes I want create entry end points I have the post get rid of the entities one more thing I would like to register a Prisma service inside the post module otherwise you will get the error now we're going to write the code in to create a new post we also need to inject Prisma Service as a dependency I'm going to copy these two lines and I'm going to paste here Post Service let me copy The Constructor we need to inject the dependency I'm going to copy my create function something is missing I have done something wrong so let's you use the Constructor pris private Prisma and Prisma service let's use this type actually I don't need that let me copy the fold create what is this now it looks good so we also need to use that post create post create input in the post controller let me import Prisma now it's time to test this application the application is running fine let's send the API request I'm going to copy my API request here I'm going to create a new post and I'm going to also create a two categories so you can use the create array inside the create array I have the category this is the post on category object so that's why I use that properties let's send the request it should be 3,000 or 3,000 it should 3,000 now you can see that one to many relation post has created successfully now it's time to do a register another post this time I don't want to create a new category create a post with existing categories I would like to create a new post and I want to use the category number one and category number two let's create a new post has created it has also made a connection with this category you can double check from the PG admin meanwhile I'm going to write the code to do relational queries let's update the find find all that looks good we also have to update the get inside the post controller now we have to fetch all the post with nestjs category so you can do that you can learn more about how to do queries in Prisma documentation I'm going to send the request the post the should be 3,000 now you can see I got these two post with the help with the I justed query with category what is my name of the database let me get it from EnV PR Nest Prisma DB here I have Nest Prisma DB let me find the tables and we have post category and categories on post let's look at the post we should have two post you can see I have one too many and transaction I must have two categories you can see that let me find categories on post here you can see I have four records there is another way to use transac ction feature if you have to perform the batch or bulk operations like delete manyu create manyu and update manyu you can use all of these in a one query you want to create three records you want to delete two records or maybe you want to update a single record or maybe you want to update five records so in that case let's say if any query fail then all of the operation will be discarded I'm going to run multiple queries at same time if any query failed you will not get result back you can use this query or transaction API when you want to create batch operation here is an example I want to find all of the post I want to find all of the artist I want to find all songs I want to find all applications in a single query if this query fails it is going to give me the this operation this complete operation will be discarded I will not get any result that is why you use this transaction API to implement the demo or to implement the transaction API let's do it in app controller we have to inject Prisma service I just want to show you the demo how can you use the transaction API this my service we have to inject it here I can say transaction let me register Prisma service now I have injected it here we have to import it sounds good I'm going to create a new method with name sequential and get sequential result results this could be the name of the query and here I'm going to copy my code so let's try to test it I'm going to run the application let me send the request for sequential query in my HTTP client sequential query HTTP Local Host colum 3000 and sequential you can see I got the result of all of my post applications this these should be post the songs and here you will have application these are all the applications with customer ID this is how it will work if you want to add include or to fetch nested record you can also do that now I'm going to talk about the concept of nested queries this topic already is in the transaction API I'm talking about transaction when you have this type of use case let's say first I have to create the customer email customer or the user and then there is an address let me look at the model structure we have a customer model and we have an address model there is a one toone relationship between customer and the address and I have created the enum application type and I have the application model and the type should be application type and default to now and I choose a loan loan here and I have made one to many relationship between application and the customer we have the applications array here so let's say I want to create a new customer address and here I'm creating a new address and here is the Fe here are the fields of customers and I'm going to create applications basically we going to we are talking about a banking type application let's say a customer comes to apply for the loan customer can apply for multiple loan applications loan car financing or business financing a customer can apply apply all of these or can can apply to one or second type application so tenure of your application would be 5 years or 2 years how many amount you want how much how much loan you want so this type of application when banking banking in banking application when an application comes they create a new customer record they create the address and they create the application based on current user or current customer demand let's say a new customer comes with business financing application John wants to get the business financing from a bank so he's decided he's going to apply for business financing application what under the hood is saying what under the hood banking application will create a new customer they will create a new address and they will also create a new application but they have a feature a customer can apply for two loans two applications or three applications he can also apply on business financing he can also apply on car financing so that's why there is a create array here what what are the benefits of using transaction under the hood Prisma is using transaction when you run the nested queries these are all the this is the nested query we are creating address and we are creating applications this is the nested query let's say if an error comes here if I will add the invalid value here it will not create the complete app application it will not create the customer it will not create the address so that is the benefit of transaction I'll show you with the help of demo this is how you can implement the nested queries in Prisma I've already done that for you I'm not going to implement it here first of I can walk walk through the code I created the customer model we have the ID we have the name field we have the email we have the address and we have the applications array so address should be here it should be at the top here so I have made a on to one relationship between address and the customer here is a unique denotes to denotes to one to one relationship we have Zip City Country inside the address and there is a on toone relationship between customer and the address but I also have one too many relationship between application and customer so I told you a John can apply for car car financing he can apply for business financing that's why I use the application array so the tenure amount application type I have set the default to loan so that was our model structure next step I have executed nested query Migration by executing this command nested queries here it is going to create the customer table it is going to create the address table and create the constraint with customer and the address it is also going to create uh application table and create constraint between application and the customer and then I have set the default value to laan and then I have created the application resource by running Nest generate resource and you will see the application inside the application module I have injected the Prisma service and then here I'm injecting the Prisma Service as a dependency and I just called create application dto by using the customer customer create input you can double check it from the customer create input you can get name email address and application all of this stuff here name email address I provided the address and I'm creating it here I also can provide the applications array you can check the type by copying it and type and paste so it should give me the this one type so I got this application create nested with custom customer input so I use the create did you see I use the create can have the array so create can have the array here so you can provide the application object here if any fails the transaction will roll back or discarded the operation let's try to test it you have to send the AP request inside the HTTP client here I'm going to send the API request John J 2 jendo City New York ZIP code this one amount he wants say 10,000 inue over 5 years and he wants business financing I'm going to create a new application you you can see a new application has created if I provide the invalid value I have set the integer here I'm providing the float or float value I got the issue now it will not create an application you can double check it from PG admin that's the benefit of transaction in this lesson you're going to learn the interactive transactions what do I mean by interactive transaction when one query is dependent on another query one query result is dependent on another query result let's take a use case you're going to build account transfer feature in banking application we're going to build this use case a John has an account in a bank and he want to he want to transfer the $100 to Sam account so what would be the process you have you have to implement as a developer you have to update the J account or deduct the $10000 from a Jone account and then you have to check the balance of JN account if balance is less than zero you have to roll back the transaction the operation should not be continue so this query result is dependent on this query result you can see if any of the step fails operation will be discarded if there is an error occurs here it will roll back the transaction so first of all we need account model we will have these properties ID balance and the title then we're going to generate migration and resource for accounts we will inject Prisma service here I will use Prisma account create input and I'm also going to update in the controller we we're going to create first account John then we will create second account which is Sam and we will implement the logic to transfer amount to One account to another account I'm going to create a route Handler for transfer we will need transfer account dto because I cannot use from from Prisma types there is no specific type for transfer account I have to use the custom data transfer object here when I will transfer I will send the transfer account request you need to provide sender ID receiver ID and the amount you want a transfer so we will create a simple basic transfer from transer method inside the account service here is the logic from the controller I will get the sender and I have renamed to from here I will have receiver I have renamed to two and I will get the amount and first we will deduct the balance from the John account by getting by getting the account on the Bas ID here decrement the amount from the John account then we try to verify the balance of the John if balance is less than zero we have to send the error back and we have to roll back the transaction here we here we got to roll back the transaction but this transaction object will do for us and this transaction function it will take all it will take it's a it's a call it's a asynchronous operation it it's going to take TX so first this is the asynchronous operation if error comes please scroll back the transaction do not deduct any amount from the John account and here is our second operation if everything is fine we got to add balance to the same account and finally we have to return the balance or return the recipient that's our trans transer process this is how you can test you have to provide the sender ID receiver ID and amount you want to transfer here I'm saying I want to transfer $50 from join account to Sam account and here I want to transfer $40 from J account to Sam account we created both account with $100 now if I try to send $20 now John will have $10 in account in his account if I try to send or deduct the $20 from Jo account you will receive this error balance is less than zero and our transaction will automatically roll back this operation that's how the transaction is helpful when your one query result is dependent on another if you want to implement it you can do it on your own but let me do that for you first of all we got to create a new model inside the schema file I have already done that model oh I have to implement here interactive transaction op schema. Prisma and we have to add a new model finally we got to run the migration migrate not a migrate also have to update here M crate our next step is to generate the accounts select the rest API let me delete entities and we have to register a Prisma service inside the account module I can register as a provider Prisma service and we have to import Prisma service Prisma service from Prisma service let's inject Prisma service inside the account service I'm going to do dependent see injection I have to copy this line and I'm going to paste it here I also need to get Prisma client so I imported the Prisma client let's rename or add a logic to create a new account we got to do the same stuff inside the account controller import Prisma let's run the application and create two accounts in our database for testing e application is running now I'm going to create a new account let me send the request for account creation board should be 3,000 not 3001 so I have created the account John now we have to create another account with Sam name account has created let's implement the transfer account logic transfer amount not an account transfer amount logic open the account controller we have to register a new route for transfer amount I'm going to create a post method we don't have transfer dto let's create that transfer dto in our dto accounts dto transfer account - D.S so here we have transfer account dto we also don't have a method yet inside the service account service so I can open account controller let me import transfer dto we don't have method I can use the vs code please declare the method inside the account service now you will have a method inside the account service this is the transfer method so here we're going to implement our logic to transfer the account from John to Sam I'm going to copy the complete op complete function I'm going to paste it here so everything is good to go now we have to test the process let's send the transfer amount request it should be 3,000 let's deduct the $50 from John account to Sam account I'm going to deduct $50 from John now you can see the balance of the Sam if I deduct the $40 again let's use it here so now the Sam has 190 and the John has $10 if I try to uh deduct $20 from John right now the balance of John is 10 it should give me the error you can see I got the error one does not have one the ID sender sender ID with one does not have enough to send $20 so I got the eror so I got the error here my transaction function automatically roll back back this operation that's why transaction is very helpful if you are doing 1020 operations or 1020 queries your one query result is dependent on another another query result is dependent on another let's imagine after 10th query there is an error then the transaction will do the roll back for you in this lesson I'm going to teach you how to upload the file in njs nestjs has already created a molter module if you have used molter in Express we're going to use the same logic they have created the molter module they also have nests platform Express to implement file upload feature so this package provides the typescript typing to work with multer package which is a middleware for handling multiart form data and then we will create our route Handler for update they have we're going to use the Interceptor that's why I use the use use Interceptor decator here we have file Interceptor they have already created this file Interceptor and you got to provide the name of your file and here we will have the upload file decorator the type should be express. multer do file that's it then it will log the file when you send the API request from Front End application or Postman to upload a file it will receive the file so this decorator indicates that the method should use the f file Interceptor Interceptor to handle the file uploads the string file inside the file Interceptor decorator refers to the field name in the request body now we're going to implement this file upload method first of all we have to install the molter type I've already attached the started kit project or if you don't have an sjs project you can create a brand new project and start from them start from there we have installed uh package now I'm going to copy the same code and I'm going to do it here inside the app controller we also need to import file Interceptor from nestjs platform Express whenever you need to upload the file you have to use the use Interceptor and they have created the file Interceptor the name of the file here you will provide the molter options when you worked with molon if you already work with molter opt molter package these are the options are same these options are same when you work with molter package so I'm not going to do it here and we will have upload file now we need to test it I'm going to start the project we need a postman to send the API request in terms of file so here I'm going to send request to the upload and we have to provide the file select the body and you got to provide file you can select the file from here a body and a file and then you have to select the file I'm going to use this PNG file you can choose any file B request I have to remove this one now I'm going to send request you can see a file has created successfully actually uploaded this is the original name this is the field file but I want to save this file some somewhere in my folder you can create a disc folder and you can save save that save there to implement this logic you going to provide these two options actually I'm going to copy the complete file intercept use intercept I'm going to copy the complete use Interceptor now it looks good so we have to import this package from disk storage I think I can get that from molter package molter disktop storage now it looks good so it will create the upload folder for me and here I will have the files folder now we're going to send the request to save upload the file and you can see there is a file inside the upload folder and inside the files we have create song mutation. PNG file you can also add a validation let's say you can say I only want to accept PNG file how can you add a validation I can say upload PNG you can do the validation upload PNG file you can implement the validation here let me copy the validation logic they provided the pars file pip Builder what this pipe Builder will do this is a custom utility that creates a pipe for validating uploaded files if you want to add a maximum size you can can accept you can also do that but I'm not going to implement that we need this logic inside the upload file here I also added an error status code if error comes it is going to log this error message unprocessable entity now it can accept only the PNG file type I've applied the pipe to add PNG validation let's test it out if I add upload PNG if I add invalid file what will happen I'm going to add jpack I got the error oh upload Das PNG I got the error for double to unprocessable entity if I provide the valid file which is PNG what will happen can get that from here this is the PNG file now the file has uploaded successfully here one more thing we got to return the message I forgot to return the message from here to also need to upload the message file uploaded successfully let's test it out out this is the PNG file you should see the message file uploaded successfully and you you will see your file here in this lesson I'm going to teach you the concept of custom decorator if you want to add additional functionality to a class to a method you can use custom decorator just like we did with app module app controller we use decorator a lot when you look at the app module here we have used a decorator this module decorator in the controller app. controller we have controller decorator it mean this decorator is adding an additional functionality to the app controller like they are adding metadata this controller can have functions attributes all of the stuff so you can improve your modularity and reusability with the help of custom decorator you can organize code very easily you can extend Nest functionality by adding custom decorator here we're going to use custom decorator I have a basic simple example we're going to create our own custom decorator the user decorator. this you use pram decorator so I can apply it on a parameter and I'm using a function this function is accepting to argument data it should be unknown type and we are getting the execution context and I can get the request from this execution context here I'm am adding a user into the request. user when you have implemented auth tication you can create a custom decorator for a user imagine you can get this request. user from a Json web token and Json web token Parts the token and found the user you can imagine that but I hardcoded it and return request. user yeah this is The Decorator Factory function it takes to parameter data and the Conta execution context and now we're going to create a new user entity here we have applied a user decorator let's say this is this is authenticated route only authenticated user can access this route so I would like to get the user so you can use a user decorator and the user entity this user decorator is going to execute this function and this function will be executed and it is going to add a user in the request EST object that's how you can implement the custom decorator let's create a new file here I can say a user decorator decorator. I'm going to copy my code user decorator you can use any name here I also need to create another entity this time I'm going to call user. entity TS now we're going to apply The Decorator on a user do I have a route I can create the complete route to implement this user decorator copy this and and paste it here and we need these two Imports now we have to test our application so whenever you need to get a user inside any function all you need to do is to apply the decorator here you can apply The Decorator upload file you can apply decorator here it depends on your use case so my application is running I'm going to create a new HTTP client. HTTP file to send API request can say that find user only based on ID we have to send the get request 3,000 slash user and you got to provide a user ID now you can see I got a user so this decorator a user decorator is calling the user decorator function and this function is getting a user or setting a user to the request object and returning the request get decorator is nothing it's just like a function here in our case I'm running a function here uh in this lesson I'm going to teach you if you want to schedule any method or any function you can do with grown task uh let's uh if you want to schedule any task let's say you want to run you want to calculate the expiry date of a license let's say your trial version is going to be expired after 7 days You're Building this type of SAS application you your company provides 14 days free trial and the trial version will be expired after 14 days what your application will do under the hood application will run a crown task it will execute every day in try to find out the expiry date for the current user if user has used software for 14 days your Chown to will determine that and it will send the notification to the user into your application hey this user has used 14 days free trial and you may must have a logic or a code to handle this situation maybe you can send the credit card information to upgrade so nestjs provide a package to implement this type of functionality we're going to we're going to we're going to install a couple of packages first you need next JS schedule and you also need or I can install it here types of grown actually I need a type as a Chone SE as a Dev dependency let's first install this package now we install the types or I can use the minus t and types Chone NJ has provide a schedule module from nestjs casual package I have to import it if you want to use this package let's import the module schedule module I have to register it or create this module this root module will initialize this casual module and it will register any declarative chrone jobs timeouts interval that exist assist within your application right now we did not Define any Crone task if you have defined Crone task this for root will initialize all of your crown task and registration occurs when the application when the own application bootstrap life cycle hook occurs now we're going to declare some cras this cronas will run the function autom automatically we will specify some specific dat time when this Crown task will run it depends on your use case do you want to run this Crown task every week or every day or every 5 minutes or every 10 minutes or every hour it depends on your use use case now we're going to create a new task service let's create a new to service so let's define our first gr task in task service private read only logger it will log some message task service do name if you want to Define a crown task you need a decorator in the previous video I taught you what are the benefits of decorator like I can extend the functionality of a function by adding the Chone decorator here you will provide your time path time date something like that so start start start you can learn learn more about this strategy by looking at Crown task schedu Nest or npm you can play around with these timing settings from this package this package you can learn more about how can you set the current dat stuff like that here the first star represent second the second star represent minute the third star represent R and the fourth star represent the day of the month and the fifth star represent the month and the last star represent the week day did you get that let's say I want to run the crown task after every 10 seconds so what I want to do I want to log a simple message after every 10 seconds and say Myron task I'm going to log a message this do logger not a throw this. logger do debug called when the current second is 10 let's try to test the application I have registered the schedule module here this for will will initialize this method and we set up the configuration to run after 10 second let's do that you can see it has run this debug after every 10 seconds what if I change the setting to five now after 5 Seconds it has executed e actually it is running called when the current second is actually it is wait it will wait for 1 minute and 5 Seconds then it will run wait for 1 minute and 5 Seconds is now you can see at 519 and then it has ran after a minute and on the fifth second what if I run this cronas after every second you can see it's running after every seconds so I can use that called when the crun C call that's it so it will wait for a minute and a 15 seconds if you want to do a little bit setting let's say I want to run every hour at the start of five uh at the start of the fifth minutes but it depends on you how you want to run this will run after every minute yep after every minute it's running this is how you can play around with crown task in this lesson you're going to learn cookies cookies are small pieces of data dat a server sends to a user browser while the user is browsing a website these cookies are stored in user device and are used to store information about the user interaction with website if you look up the Google Chrome you will see the developer tools and you can find the application tab here you will find all of your cookies if you have stored we have only single cookie you can Implement also cookie based authentication just like we did in authentication module we saved at Json web token into a local storage but if you were if you work with a local storage or front-end application you can store your Json web token in this storage but you can also use a cookie and you can save your token in encrypted format so these are all the use cases of cookies like most of the time when you when you access or fetch or look at the same look at the website or when you visit the same website again and again the next time it tries to fetch the data from your cookies it has saved all of your authentication Lo all of your password in cookies when you go to the Google password manager where all of this data is stored all of this data is stored in your cook is remember when you look at the history or let me you look at the history if you want to delete all of your data it will also ask you hey do you want to do you want to delete all of your cookie stuff you have data inside the cookie so you can save any token inside the cookie let me talk about the use cases of cookies you can manage user sessions let's say if you want to expire a user session after 30 days or after 24 hours you can have that type of logic in cookie and this cookie will be stored here inside the application and the cookies tab if you have any type of shopping cart application you can also do a little bit saving in the in the cookies let's say a user has uh add added three to four items to the checkout and he left the website and then you can send user hey you left something a user can see all of his checkout items you can do some type of tracking and analytics you can do authentication like cookies can help with authentication and security by storing tokens or other information that verifies a user identity you can use load balancing State Management and cashing stuff with cookies now I'm going to implement the cookies in NS project you got to install these two packages I have already installed them I've already installed in my package.json file this is the cookie parser you need and then you also need a typing for cookie parser go ahead and install them all right our next step is to register a cookie parts sir in main.ts file this is our main entry file here I have registered a cookie parser you can import it as a star and here if you want to add add your secret you can do it here or if you want to add uh some logic or decode something like that this is the option from a cookie package you can go to cookie parser so this package is similar to this one this one cookie parser but you can look at the documentation what type of options you have now our next step is to set the cookie I'm going to create a new route to set the cookie and we need a response from the nestjs comment and response type from the Express package here I'm allowing the framework you can set the cookie I am I'm going to set the cookie cooking token name encrypted cookie string something here it's a key value PA here and I'm sending a message cookie saved successfully here here I'm trying to log all of your cookies and return cookies in the get route now we need to test the application when you look the app controller here let's say I'm want to set a new cookie I've already saved that cookie in my application when you look at the Local Host colon application tab here we have the cookie let's say I want to set a new cookie it should be let's say a user token or authenticated token something like that JWT or JWT encrypt something like that yes jw. iio so what I want to do I want to so let's can I do that let's add this payload here or you can say I want to add a user ID let's say token I'm going to add a user ID let's say a mongod DB ID or you can say user ID so let's send the request from our browser to first set the cookie so I can set the request please set the cookie cookie saved successfully and you can see your user ID here this one but it did not encrypt but it did not save as encrypted you have to save your encrypted value here let's say I'm going to copy this token and you got to paste it here now I have an encrypted value so cookie saved successfully what if I try to get the cookie get all of my cookie it is going to give me the user ID and cookie token name that's how if you want to implement cookie based authentication you can do that if you want to implement High intent intensive task then you need cues High intensive task mean sending emails generating reports processing images or any task that can be offloaded from the main application flow with the help of cues you can manage in process task in the background without blocking the main application execution so you can use cues in task generation when you you identify task that can be processed asynchronously let's consider sending an email after a user register instead of sending email directly with the registration endpoint you can push the task of a sending email to a queue so this task is executed in the background separate from the main application thread this this ensure that the main application remains responsive and does not get blogged by the time consuming tasks so if you have highly CPU intensive task then you can use qes let's dive into the implementation of cues in nestjs nestjs provided the bull package they have written their own implementation by using the original bull package you have to install the package first I'm going to install the nestjs bll I also need to install npm B npm install B the simple bull package nextjs pull is using the redish under the hood so you need radish caching Library make sure you have Docker in your system we're going to use Docker to pull redish image I'm not going to install redish separately so that's why I'm going to use docker now let's create a new module our application what we want to do we're going to create a fake implementation to convert do wave audio file to MP3 we're going to write fake implementation let's say you have a use case where you want to convert do wave file to MP3 or you have an application where you need this functionality you want to convert video MP4 to MP3 in that case you need a q let's create a new audio module we're going to write implementation here to convert do wave file to MP3 then we need a docket compose we're going to use redish image now we're going to set up Ries in the docket compose file let's create a new file inside the root directory I'm going to do it here docket compos yl let's rename it to yl so we have to in start the docker compose my Docker is running now let's install Docker compose up it will pull the redish image from the docker Hub but I have already pulled Docker radish image so my radish server has started I think I've already installed another extension to work with redes if you want you can install that here you can see the redis I have installed this one database manager for my SQL Maria B post sqlite and redis here you will see the database if I try to create a connection for the redes Local Host 6379 that's my port so I can connect now now you will see all of my databases so this is my current or the latest I'm going to delete the rest of the other now I have the empty let's remove everything let's connect so I have the audio que so get rid of this one now we have the empty data SP now we need to register a bull module so in the app module I'm going to register it here your module and I'm going to do it here make sure you imported a bull module bull module import from Nest CHS SGS Bull and bull module so I'm going to open a new tab to run my application next we need to register a queue inside the audio module you will find the audio module here so we got a register it here make sure you imported the bull module and I'm going to copy that and let me paste it here so this register Q This method is used to register a queue with your within your application it takes an optional object as an argument to configure the que we have provided the name of our Q audio q and this is the name you will see the name here here it should be the audio Q this one where is my redish yep you will see the audio queue here let's move forward now we're going to create a convert end point I'm going to copy that into audio controller and I'm so we have audio Q let's imagine we would like to convert v file into MP3 this is my I'm just writing the fake implementation we are not writing the exact logic to convert the file but you can do that this is just a file name this is an optional object so this will add a new entry inside the Q so we have injected the audio q i got this Q from from The Bu package the type now we need a processor to process the queue let's define a new audio processor audio. processor. it would be a service or provider so we got to register it here inside the providers AIO processor so here when you want to process this when the application wants to process it is going to call this handle convert this job will take this argument as a job here inside the audio processor so I'm just trying to do the log here let's run the application to convert W file to m B3 we have to send the convert request so in the HTTP client I'm going to send the post request convert let's say dot v file to MP3 post HTTP Local Host Callum 3000 SL audio SL convert I don't need to provide any argument but if you want to provide argument or or request body you can do that now you can see it has run successfully I got this message starting wave file inside the audio processor here starting start converting v file to MP3 and I got the object which is sample. W file which which I have passed here whatever you pass here it will be received here inside the job. data and finally it has completed this one if you have any type of logic to convert P file to MP3 you will Implement here here but what if I look up the database do you have this one convert yep you can see the bull and we we have the audio Q this is our message I can show you here you can see the name is convert which we named here the convert this one q key key is here convert convert and the data is sample. W file and all of these metad data what if I provide additional data let's say ID which is one so it is going to save also ID let's run the request you can see I got the file and ID and Let me refresh it I'm going to connect uh you can see file sample do wave and you can see the ID the name is convert and the audio CU which is we have named here here inside the audio module this is the audio Q in this lesson I'm going to teach you the event emitter in nextjs event emitor is a mechanism that allows different parts of your application to communicate with each other and even driven approach so you can learn more about you can do communication between module Services components or classes under the hood nestjs uses event emiter to collaborate with these services and modules and components so an event emitter works with Publisher and subscriber pattern if you heard about this design pattern or you have used this design pattern now we're going to talk about some practical use cases of event emitter you can do module communication you can send the notification system we're going to use this use case in the previous video we have converted wave file to MP3 now I want to convert I want to send the notification if the file has successfully converted we need to send the notification to the user we can also use from for Real Time updates if you have any plugin syst system you can do with the help of event emitter you can achieve logging and monitoring you can do error handling and Reporting this one is also useful you can Implement in user authentication and authorization for example authorization service could emit an event when user logs in and other parts of application can respond Accord accordingly let's say user has logged after 10 days your you can your system or your application can have notification you can also Implement in the caching and management in our case we're going to take example from our previous example let's say you want to send the notification when w file converts successfully into MP3 format you can use event emitter to send the notification you got to install the package first nestjs event emitter and Next Step you got to register the event emitter in the app module let me change my Branch here event emitter Pro we got to create install event emitter again because I was in a different branch let's install it we have event emitter let's register it in the app module I'm going to do it here we have to import the event emiter module I have to import it manually event emitter module from nestjs event emiter that looks good we have registered the event emitter module this will register all of your event listener or or create all of your event listener we will have audio converted listener it's a service it's a provider this we have just a method it will accept the event and the audio event we will create the type this is the name of the listener or the name of the event that's why I used on event here when you emit the event this audio converted event this function will be called we're going to emit this event in the handle convert in the previous video we used this method to convert fave into MP3 so when you emit this event this method will be called so you can have any type of logic here maybe you will have an email service and your email service will have a method to send email let's create a new file I'm going to copy all of the code this is a provider we're going to in we're going to create inside the audio converted what's the name of the file audio converted listener I can say audio do converted or you can say audio converted listener. so we have this file we did not create this type let's create this type in audio folder I can say audio actually we can do it in an events folder we're going to store all of the types audio converted event. it's nothing it's just a type for types typescript class it looks good make sure you register your provider in the audio module so audio converted listener now we need to import we need to emit this event in your handle convert we have done it in the processor while converted successfully and you can send a message make sure you have import or inject event emitter event emitter event emitter 2 from njs event emitter package njs event emiter oops event emiter I don't know why they use two so I'm going to use the same stuff two event emitter to and we have emit this event this one now we have to test the application let's run the application I think do I need a Docker let's run the application yes I need a Docker let's install the uh let's start the docker first because we were using redes when we were building this Q so this Q is dependent on bull module is dependent on rades let me start my Docker now my Docker is running now let's run the application to test this event emitor we have to send the API request to convert fa file to MP3 it should log the message actually it should run this event this meth let's send the request I'm not able to send the request why saying waiting I think I did something wrong here look at the audio processor or audio controller wa I think it is not calling this method or emitting this method emitting this IM event oh I think we did not stop part that is server let's do it I'm going to send the request connect with r so it has X executed successfully and I got the message notification has sent to the user that file is converted successfully so I also loged the event that looks good we have successfully achieved our desired use case here it has emited the event I also passed a data object from the Q job. data which we were sending from here so I received the same object inside the event listener here I received the same event here and here I locked the event the first one is the event and the message notification has sent to user successfully this is how you will Implement event emitter in nestjs in this lesson I'm going to teach you the streaming in sjs streaming is the process of sending or receiving data in small chunks called streams rather than sending or receiving the entire data at once the concept is based on stream API in nodejs and is utilized for more efficient data handling especially when dealing with large amounts of data such as files Network request or realtime data Transmissions you can use streaming for file upload and file download you can do realtime communication if you have to build a media streaming type application like Netflix then you need streaming API API responses reading and writing from stream when processing data from sources that generate data incrementally such as reading log file or parsing large XML or Json documents you can do some data aggregation server sent events database operations proxy servers all of these practical use cases of streaming in this video I'm just showing you how to download a file with the help of streaming we need a nest controller a file controller here I will specify a a a method it will download the file from this crun project as a package.json file it is going to save in my computer this is another customized way to download the file when you download the file with this method it will download the exact package.json file here it will not download with extension only text file let me show you the difference between them let's create a new controller open the file controller let me import some dependencies and we need to use this method to download the file I'm going to create a new method here let's run the application let's try to send the request to the file file we have the endpoint file and the stream file file and stream file now it is going to download the package.json file you can see it is giving just only a stream file it did not download with package.json file if I open the file you will see it is nothing more it's just a simple text file in a Json format but we going to we want to download the exact Json file you can do the same stuff when you down when you want to download images or video you have to specify here the content type should be video or audio it depends on your use case and you also can provide the name of your file just like we did the package.json file you have to do it content dispo dis disposition now we're going to copy the same part method and place it here it will return a streamable file I have created the stream by you joining the path which is this one I'm referring to package.json file file and finally I'm setting the response by setting application Json my file name would be this one act as the attachment and finally it is going to return the streamable file now if I go to this endpoint file and/ stream file customize what will happen now it is going to do stream file customize. Json on not not it should be Json now it is going to see you will see the package.json file I already downloaded the package.json file when we were when I was practicing this I can replace that you will see the package.json file I have opened the file in my Mozilla Firefox you can see your the package Json file we have scripts we have all the dependencies and we have the dev dependencies this is how you can download any file if you have images you can specify your image format or you can name the file name or your image file name you can also set your image content type in this lesson you're going to learn this session in sjs session refers to the concept of maintaining stateful data between consecutive request from the same client a session allows you to send allows you to store and retrieve user specific information on the server server on the server across multiple request typically using cookies to identify the session if you have used session based authentication in your project the concept is same you can use session to maintain the authentication state of a user when a user log in logs in session can be created with their authen authentication data and subsequent request can be authenticated based on the session you can use session in authorization user preferences shopping cards user tracking caching personalization and form data persistence we going to use the express session let's install these two packages I have already installed in my package.json file session Express session and the next package you need type of Express session then our next step is to register a middleware when you go to main.ts you got to register it here AB do session make make sure you import your session from the express session you can use any secret key you can also set resave you can read the documentation of resave what this resave is doing you can also read the documentation of save uninitialized you can find documentation here from the express session when you check a save or resave here you will find the documentation uninitialized initialized you can also find the documentation of uninitialized next we have app controller here I'm going to create a simple route to login let's say uh a user wants to log in when logged in successfully we have verified the user from the database then you can set the user into the session I have set the object ID and the username and when later user wants to access his profile he can do that because we have saved the user in the session so here if there is a user in the session it is going to return user else not logged in you can test it simple by sending the login request it is saying a user has logged in just like we did just like it did if I said if I try to retrieve the profile it is going to give me the profile because we have set that user when we were logged in this one now I got this hello with the user and the name this is how uh if you use Json web token we basically stored a Json web token in the storage but if you want to use session based authentication on front end you can do that\n"