masamune_auth_google 3.2.0

Authentication plugin for Masamune that can implement Google sign-in.

Masamune Auth Google

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Masamune Auth Google

Usage

masamune_auth_google adds Google Sign In to the Masamune/Katana authentication stack. It is intended to work alongside:

• katana_auth – core authentication abstractions
• katana_auth_firebase – optional Firebase Authentication integration
• masamune_auth_google_firebase – helper for exchanging Google credentials with Firebase

Installation

Install the base packages first:

flutter pub add katana_auth
flutter pub add katana_auth_firebase

Then add Google support:

flutter pub add masamune_auth_google
flutter pub add masamune_auth_google_firebase

Register Adapters

Configure adapters near the root of your app so Google Sign In works across the application.

// lib/adapter.dart

/// Masamune adapters used in the application.
final masamuneAdapters = <MasamuneAdapter>[
  const UniversalMasamuneAdapter(),

  const GoogleAuthMasamuneAdapter(
    clientId: "YOUR_GOOGLE_CLIENT_ID",
  ),
  FirebaseGoogleAuthMasamuneAdapter(
    functionsAdapter: const FunctionsMasamuneAdapter(),
  ),
];

Note: This package requires katana_auth and katana_auth_firebase to be installed separately. Those packages provide the core authentication infrastructure.

Provide the appropriate clientId for the platform. On Android, configure the reversed client ID in the manifest; on iOS, update the URL types in Info.plist.

Authenticate Users

Use Authentication from katana_auth to start the Google Sign In flow.

class SignInPage extends PageScopedWidget {
  @override
  Widget build(BuildContext context, PageRef ref) {
    final auth = ref.app.controller(Authentication.query());

    // Initialize on page load
    ref.page.on(
      initOrUpdate: () {
        auth.initialize();
      },
    );

    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            if (auth.isSignedIn)
              Column(
                children: [
                  Text("Welcome!"),
                  Text("User ID: ${auth.userId}"),
                  Text("Email: ${auth.userEmail ?? 'N/A'}"),
                  TextButton(
                    onPressed: () => auth.signOut(),
                    child: const Text("Sign Out"),
                  ),
                ],
              )
            else
              ElevatedButton.icon(
                icon: Icon(Icons.g_mobiledata),
                label: const Text("Sign in with Google"),
                onPressed: () async {
                  try {
                    await auth.signIn(GoogleAuthQuery.signIn());
                  } catch (e) {
                    print("Sign in failed: $e");
                  }
                },
              ),
          ],
        ),
      ),
    );
  }
}

The Authentication controller notifies listeners when state changes, automatically rebuilding dependent widgets.

Firebase Integration

If you also install masamune_auth_google_firebase, the adapter will exchange Google credentials for Firebase tokens. Ensure your Cloud Functions endpoint (or Firebase SDK) validates the Google ID token and returns Firebase credentials.

Platform Setup

• Android: Configure SHA-1 fingerprints in Google Cloud Console and add the generated configuration (google-services.json).
• iOS: Add the reversed client ID to URL schemes in Info.plist and include the GoogleService-Info.plist file.

Tips

• Test on real devices to ensure Google Play Services or the iOS Google Sign In flow works as expected.
• Provide clear error messages if the user cancels the sign-in process.
• Combine with other providers (Apple, Facebook, etc.) using auth.link to support multi-provider accounts.
• Log sign-in attempts with AuthLoggerAdapter for analytics.

GitHub Sponsors

Sponsors are always welcome. Thank you for your support!

https://github.com/sponsors/mathrunet