Discussion on: Part 2/3 - How to create a server-side timer using WebSockets (with Socket.IO), NestJS and Flutter

Hi @markbloomfield, thanks for your feedback. The reason I didn't include this part in the original tutorial series was because I thought it would complicate things for a reader. But if you are interested in an authenticated flow, I can extend the tutorial series with a part 4.

For now, Yes, you have to implement AuthService separately and use it within the AuthenticatedSocketIoAdapter class. To use it, you can use the variable this.authService. In fact, the const user = await this.authService.authenticateToken(token); line actually tries to authenticate the user using the token sent from frontend, and return the user object for that authenticated user.

For example, if the AuthService uses Firebase as the Auth provider, the AuthService class would look something like,

@Injectable()
export class AuthService {
  constructor(
    private readonly userService: UserService,
    private readonly firebaseService: FirebaseService,
  ) {}

  async authenticateWithFirebase(idToken: string) {
    try {
      const decodeUser = await this.firebaseService.auth.verifyIdToken(idToken);

      if (!decodeUser) {
        throw new UnauthorizedException();
      }

      const { sub, groups } = decodeUser;

      const user = await this.userService.getUserByFirebaseUid(sub); // Get user from db.

      return user;
    } catch (e) {
      throw new SocialAuthenticationException();
    }
  }
}

In the above code, the authenticateWithFirebase method call is used within the AuthenticatedSocketIoAdapter class.

Here the injected,

• FirebaseService class contains just the firebase initialisation code.
• UserService class contains the database-related methods (CRUD methods mainly) for user data.

Please tell me if this is not clear and please also tell me if I should extend the series with a part 4 explaining the authentication.