Dependencies

• npm install @prisma/client
• npm i prisma -D
• npm i -D class-validator class-transformer
• npm i argon2 --hash password--
• npm i @nestjs/passport passport passport-local ---login----
• npm i -D @types/passport-local
• nest g gu auth/guards/local-auth ---guards----
• npm i @nestjs/jwt @nestjs/config
• npm i passport-jwt
• npm i -D @types/passport-jwt
• npm i passport-google-oauth20
• npm i -D @types/passport-google-oauth20

Description

Nest framework TypeScript starter repository.

Project setup

$ npm install

Compile and run the project

# development
$ npm run start

# watch mode
$ npm run start:dev

# production mode
$ npm run start:prod

Run tests

# unit tests
$ npm run test

# e2e tests
$ npm run test:e2e

# test coverage
$ npm run test:cov

Auth Flow

1. Signup Flow

Client Sends a Signup Request:

• A POST request is made to the /auth/signup endpoint with the user’s email and password.

AuthController Handles the Request:

• The registerUser method in the AuthController receives the request.
• It extracts the data from the request body, validates it using the ValidationPipe, and forwards it to AuthService.registerUser().

AuthService Creates the User:

• The AuthService checks if a user with the same email exists by calling UserService.findByEmail().
• If no user exists, it creates the user using UserService.create().
• The new user is now registered.

Response:

• The user receives a success response confirming the registration.

2. Login Flow with Guard Protection

Client Sends a Login Request:

• The client sends a POST request to /auth/login with an email and password in the request body.

LocalAuthGuard is Triggered:

• The loginUser() method in AuthController is protected by the LocalAuthGuard.
• When the request hits /auth/login, LocalAuthGuard.canActivate() is executed first to validate the user before the controller handles the request.

canActivate() in LocalAuthGuard Validates the User:

• The guard extracts the email and password from the request.
• It calls AuthService.validateLocalUser() to validate the user’s credentials.

AuthService Validates the Credentials:

• In validateLocalUser(), the service:
  • Finds the user by email using UserService.findByEmail().
  • If found, it verifies the password using argon2.verify().
  • If credentials are valid, it returns the user’s ID and email.

Request Object is Updated by the Guard:

• If the user is valid, LocalAuthGuard attaches the user object to the request (via request.user = user).
• The request now contains the authenticated user’s data, and canActivate() returns true, allowing the request to proceed to the controller.

AuthController Handles the Login:

• Now that the guard has validated the user, the AuthController.loginUser() method is called.
• It receives the authenticated user from the request object.

AuthService Generates the JWT Token:

• Inside loginUser(), the AuthService.generateTokens() method creates a JWT token with the user’s ID (sub field).
• The response includes the JWT token, user ID, and email.

Response:

• The client receives a response with the user’s ID, email, and access token.

Client → Sends POST /auth/login (with email & password) LocalAuthGuard → Triggers canActivate() AuthService → validateLocalUser(email, password) Verifies user’s existence and password. LocalAuthGuard → Attaches user to request.user. AuthController → Calls loginUser() method. AuthService → Generates JWT token. AuthController → Sends response (user ID, email, access token).

License

Nest is MIT licensed.