How to redirect to a specific path after authentication in Nest using Passport

ONLINECAST

2 min read

·

29-08-2024

17

0

Share

Redirecting Users After Authentication in NestJS with Passport

This article addresses a common challenge faced by developers using NestJS and Passport for authentication: controlling redirection after a successful authentication based on the specific authentication flow (login vs. connect).

The scenario presented involves a NestJS backend and an Angular frontend, where authentication is handled by Passport with various strategies like Local, Magic Login, Google, and Facebook. The primary goal is to redirect users to specific paths based on whether they are logging in or connecting a social account to their existing local account.

Understanding the Problem

The issue lies in the redirection behavior after Google authentication. When a user successfully authenticates with Google, the OAuth flow redirects them back to a specific path on the NestJS backend, making it difficult to determine if the user initiated a login or a social account connection. This lack of context hampers proper redirection to either / for login or /app/manage-profile for connecting accounts.

The Solution: Distinctive Callbacks

The key is to use distinct callback URLs for login and connect flows. This approach allows the backend to determine the user's intent based on the received callback URL.

Implementation Steps

1. Separate Callback URLs:

   • Define unique callback URLs for login and connect flows. For example:

     • Login: /api/auth/callback/google/login
     • Connect: /api/auth/callback/google/connect

2. Update Google Configuration:

   • In your Google OAuth configuration, set the redirect_uri parameter to the respective callback URLs.

3. Implement Callback Handlers:

   • Create separate controllers or routes to handle these callback URLs. For instance:

     • api/auth/callback/google/login: Handle login flow.
     • api/auth/callback/google/connect: Handle connect flow.

4. Differentiate and Redirect:

   • In each callback handler, you can now differentiate between login and connect flows based on the URL path.
   • Redirect users accordingly:
     • /api/auth/callback/google/login -> /
     • /api/auth/callback/google/connect -> /app/manage-profile

Example Code Snippet (Google Login/Connect)

@Controller('auth')
export class AuthController {

  @UseGuards(AuthGoogleAuthGuard)
  @Get('callback/google/login')
  async loginGoogleCallback(@Req() req: Request, @Res() res: Response): Promise<void> {
    // Handle login logic
    // ...

    res.redirect('/');
  }

  @UseGuards(AuthGoogleAuthGuard)
  @Get('callback/google/connect')
  async connectGoogleCallback(@Req() req: Request, @Res() res: Response): Promise<void> {
    // Handle connect logic
    // ...

    res.redirect('/app/manage-profile');
  }
}

Key Considerations

• Security: Employ appropriate security measures like HTTPs and secure token handling to protect user data during authentication and redirection.
• State Management: Consider using session or state management strategies to track user authentication state and avoid potential issues with multiple redirects.

Beyond Google:

This approach can be extended to other social login/connect providers like Facebook by implementing distinct callback URLs and handlers for each strategy.

Conclusion

By utilizing separate callback URLs for login and connect flows, you gain the ability to differentiate user intentions and redirect them to the appropriate destinations after successful authentication. This enhances user experience by providing seamless and contextually relevant navigation, leading to a more streamlined and secure authentication process.