Getting started with Flutter authentication

Summary

This tutorial shows how to add Google authentication to a cross-platform Flutter application using the Supabase SDK for Flutter. It explains OpenID Connect as a protocol built on OAuth 2.0, then configures Google Cloud client IDs for iOS, Android, and web, with Supabase using the web client ID to verify the supplied identity token. The sample initializes Supabase, starts Google sign-in through google_sign_in, passes the resulting access and ID tokens to signInWithIdToken, and listens for signed-in events to navigate from LoginScreen to ProfileScreen. The profile reads avatar_url and full_name from Supabase userMetadata, while a sign-out action returns the user to the login screen, producing a basic personalized app.

Takeaways

1. 1

   Supabase's signInWithIdToken method accepts the Google ID token and access token, then makes the token's content available through the Supabase user's userMetadata.

2. 2

   The Supabase Google provider configuration uses the web client ID as an Authorized Client ID; Android and iOS client IDs are configured for their respective platforms.

3. 3

   The sample's ProfileScreen displays avatar_url and full_name from userMetadata and returns to LoginScreen after calling supabase.auth.signOut().