Register and login authentication in Nestjs

Nestjs

Authentication

* Authenticate a user by verifying their "credentials" (such as username/password, JSON Web Token (JWT), or identity token from an Identity Provider)
* Manage authenticated state (by issuing a portable token, such as a JWT, or creating an Express session)
* Attach information about the authenticated user to the Request object for further use in route handlers

Authentication requirements :

* Let's flesh out our requirements. For this use case, clients will start by authenticating with a username and password. Once authenticated, the server will issue a JWT that can be sent as a bearer token in an authorization header on subsequent requests to prove authentication. We'll also create a protected route that is accessible only to requests that contain a valid JWT.

* We'll start with the first requirement: authenticating a user. We'll then extend that by issuing a JWT. Finally, we'll create a protected route that checks for a valid JWT on the request.

First we need to install the required packages. Passport provides a strategy called passport-local that implements a username/password authentication mechanism, which suits our needs for this portion of our use case.

  npm install --save @nestjs/passport passport passport-local
  npm install --save-dev @types/passport-local

NOTICE
For any Passport strategy you choose, you'll always need the @nestjs/passport and passport packages. Then, you'll need to install the strategy-specific package (e.g., passport-jwt or passport-local) that implements the particular authentication strategy you are building. In addition, you can also install the type definitions for any Passport strategy, as shown above with @types/passport-local, which provides assistance while writing TypeScript code.

Encryption and Hashing :

First install required packages:

npm i bcrypt npm i -D @types/bcrypt
Once the installation is complete, you can use the hash function, as follows:

import * as bcrypt from 'bcrypt';
JWT functionality#

We're ready to move on to the JWT portion of our auth system. Let's review and refine our requirements:
Allow users to authenticate with username/password, returning a JWT for use in subsequent calls to protected API endpoints. We're well on our way to meeting this requirement. To complete it, we'll need to write the code that issues a JWT.
Create API routes which are protected based on the presence of a valid JWT as a bearer token
We'll need to install a couple more packages to support our JWT requirements:

npm install --save @nestjs/jwt passport-jwt npm install --save-dev @types/passport-jwt