Masamune Auth Facebook

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Masamune Auth Facebook

Usage

masamune_auth_facebook integrates Facebook login with the Masamune/Katana authentication stack. It is intended to work alongside:

• katana_auth – core authentication abstractions
• katana_auth_firebase – optional Firebase Authentication integration

Installation

Install the base packages first:

flutter pub add katana_auth
flutter pub add katana_auth_firebase

Then add Facebook support:

flutter pub add masamune_auth_facebook

If you need to link Facebook with Firebase, also install:

flutter pub add masamune_auth_facebook_firebase

Register Adapters

Configure adapters near the root of your application so the Facebook SDK can authenticate properly.

// lib/adapter.dart

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

  const FacebookAuthMasamuneAdapter(
    clientToken: "YOUR_FACEBOOK_APP_ID",
    clientSecret: "YOUR_FACEBOOK_APP_SECRET",
  ),
];

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

FacebookAuthMasamuneAdapter handles the native login flow and provides access tokens to the Katana authentication layer.

Authenticate Users

Use Authentication from katana_auth to initiate the Facebook 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.facebook),
                label: const Text("Sign in with Facebook"),
                onPressed: () async {
                  try {
                    await auth.signIn(FacebookAuthQuery.signIn());
                  } catch (e) {
                    print("Sign in failed: $e");
                  }
                },
              ),
          ],
        ),
      ),
    );
  }
}

The controller automatically notifies listeners on state changes.

Firebase Integration

If you also include masamune_auth_facebook_firebase, add the Firebase adapter and ensure you exchange Facebook credentials for Firebase tokens on the server (via Cloud Functions) or directly with the Firebase SDK.

FirebaseFacebookAuthMasamuneAdapter(
  functionsAdapter: const FunctionsMasamuneAdapter(),
),

Facebook Platform Setup

• Create a Facebook app and obtain the App ID and App Secret.
• Configure redirect URIs, bundle IDs, and package names in Facebook Developer settings.
• Update your iOS and Android projects with the required meta-data (e.g., AndroidManifest.xml, Info.plist).

Tips

• Test on real devices; browsers and simulators may have limitations when invoking the Facebook app or WebView.
• Provide fallbacks or alternative sign-in options for regions where Facebook is unavailable.
• Monitor token expiration and refresh logic if your app relies on long-lived sessions.
• Pair with AuthLoggerAdapter to capture login analytics.

GitHub Sponsors

Sponsors are always welcome. Thank you for your support!

https://github.com/sponsors/mathrunet