PassportStrategy validate method should support Rxjs Observerable as return type

[hantsy]

Feature Request

Is your feature request related to a problem? Please describe.

Add Obseverable as an option of the return type.

Describe the solution you'd like

I would like to use Rxjs API as possible in my application because I have some experience of Angular, but unfortunately, in the NestJS application, it mixes Promise and Observable.

I try to use Observable as validating return type, it does not work.

@Injectable()
export class LocalStrategy extends PassportStrategy(Strategy) {
  constructor(private authService: AuthService) {
    super({
      usernameField: 'username',
      passwordField: 'password',
    });
  }

 validate(username: string, password: string): Observable<any> {
   return this.authService
     .validateUser(username, password)
     .pipe(throwIfEmpty(() => new UnauthorizedException()));
 }
}

Teachability, Documentation, Adoption, Migration Strategy

Currently, it only supports Promise, and any simple type, but does not support Rxjs Observable.

  async validate(username: string, password: string): Promise<any> {
    const user = await this.authService
      .validateUser(username, password)
      .toPromise();

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

    return user;
  }

What is the motivation / use case for changing the behavior?

Support Rxjs Observable

[jmcdo29]

It absolutely does support promises. You can see an example here (local) and here (google)

[hantsy]

@jmcdo29 I will verify it one more time, I have changed my codes to Promise to make it work now. Thanks.

[hantsy]

Maybe the pipe is not correct.

.pipe(throwIfEmpty(() => new UnauthorizedException()));

I am not sure if the user not found what Mongoose returns. All mongoose API are using Promise.

[jmcdo29]

Can't say with the rest of your code, as it isn't visible, but it is possible. For further support, please use our Discord. You're also welcome to look through the rest of the project above to see if it can help you find your problem

[hantsy]

OK, Thanks.

[Jintus]

I do not understand why this Issue as been closed.

The suggested code from @hantsy works well if we add firstValueFrom operator to transform Observable into Promise but if we use the code as it, the request attribute user will be populate with the observable, so the controller will be triggered.

For this controller :

@UseGuards(LocalAuthenticationGuard)
@Post('/auth/login')
login(@Request() req: { user: AuthenticatedUser }) {
  console.log('Controller', req.user);
  return req.user;
}

---

With bad credentials :

async validate(email: string, password: string): Promise<AuthenticatedUser | undefined> {
  return firstValueFrom(this.authenticationService.validateUser(email, password).pipe(
    throwIfEmpty(() => new UnauthorizedException())
  ));
}

// Will not trigger Controller console log

async validate(email: string, password: string): Observable<AuthenticatedUser | undefined> {
  return this.authenticationService.validateUser(email, password).pipe(
    throwIfEmpty(() => new UnauthorizedException())
  );
}

// Will trigger Controller console log, with req.user to be the entire Observable

[kamilmysliwiec]

Please, use our Discord channel (support) for such questions. We are using GitHub to track bugs, feature requests, and potential improvements.