secure_session_manager 1.2.0

A lightweight, secure, and highly scalable session management package for Flutter with zero performance overhead, automatic token refresh, and built-in interceptors for Dio and http.

secure_session_manager

A lightweight, secure, and highly scalable session management package for Flutter apps with zero performance overhead when optional features are disabled.

Features

• 🔐 Secure Storage: Uses flutter_secure_storage for persisting tokens.
• 🚀 Performance: In-memory caching for sub-millisecond token access.
• 🔄 Atomic Refresh: Automatic token refresh with a mutex to prevent multiple simultaneous refresh calls.
• 🚦 Request Queueing: Queues pending requests during an active token refresh.
• ⏳ Idle Timeout: Optional, event-driven idle detection (no polling).
• 📱 App Lifecycle: Automatically validates session on app resume.
• 🌐 Interceptors: Pre-built Dio and http interceptors for automatic token injection and 401 handling.
• 🧩 JWT Support: Automatic expiry detection from JWT payloads.
• 📦 Flexible Storage: Use SecureStorageProvider (default) or SharedPreferencesProvider.
• 🧪 Testable: Designed with dependency injection for easy unit testing.
• 🔋 Zero Overhead: Optional features are only instantiated if enabled.
• 🛡️ Infinite Loop Prevention: Smart retry markers to prevent refresh loops.
• 📡 Rich Event System: Comprehensive event streams for auth state changes.
• 🔄 Safe Multipart Replay: Proper file stream handling for retried multipart requests.
• 🎯 Refreshing State: Track when token refresh is in progress.

Installation

Add to your pubspec.yaml:

dependencies:
  secure_session_manager: ^1.2.0

Quick Start

1. Implement TokenProvider

Implement this interface to define how your app refreshes its authentication tokens.

class MyTokenProvider implements TokenProvider {
  @override
  Future<SessionToken> refreshToken(SessionToken currentToken) async {
    // Call your API to refresh the token
    final response = await http.post(
      Uri.parse('https://your-api.com/refresh'),
      body: {'refresh_token': currentToken.refreshToken},
    );
    
    final data = jsonDecode(response.body);
    return SessionToken(
      accessToken: data['access_token'],
      refreshToken: data['refresh_token'],
      expiresAt: DateTime.now().add(Duration(hours: 1)),
    );
  }

  @override
  Future<void> revokeToken(SessionToken token) async {
    // Optional: Call your API to revoke the token on logout
    await http.post(
      Uri.parse('https://your-api.com/revoke'),
      body: {'token': token.refreshToken},
    );
  }
}

2. Initialize SessionManager

Initialize the singleton at the start of your app.

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  await SessionManager.instance.initialize(
    tokenProvider: MyTokenProvider(),
    // Optional: Configure idle timeout
    idleTimeout: Duration(minutes: 15),
    // Optional: Enable lifecycle observer (default: true)
    enableLifecycleObserver: true,
  );
  
  runApp(MyApp());
}

3. Networking Interceptors

The package provides built-in interceptors for Dio and http that automatically:

1. Inject the Authorization: Bearer <token> header.
2. Intercept 401 Unauthorized errors.
3. Trigger a token refresh and replay the failed request seamlessly.

For Dio

final dio = Dio();
dio.interceptors.add(SecureSessionDioInterceptor(dio));

For http package

final client = SecureSessionHttpInterceptor(http.Client());
// Use 'client' instead of 'http' for your requests

4. JWT Automatic Expiry

If your accessToken is a JWT, the package can automatically extract the exp claim.

final token = SessionToken(accessToken: "your.jwt.token");
print(token.expiresAt); // Automatically parsed if not provided

5. Manual Session Control

// Save session on login
await SessionManager.instance.setSession(token);

// Get current token (auto-refreshes if expired)
final token = await SessionManager.instance.getAccessToken();

// Get full session details
final session = await SessionManager.instance.getSession();

// Logout / Clear session
await SessionManager.instance.logout();

Advanced Features

Idle Detection

Option 1: Using IdleListener widget (Recommended)

await SessionManager.instance.initialize(
  tokenProvider: MyTokenProvider(),
  idleTimeout: Duration(minutes: 15),
);

// Wrap your app with IdleListener
return IdleListener(
  child: MaterialApp(...),
);

Option 2: Manual setup

return Listener(
  onPointerDown: (_) => SessionManager.instance.touch(),
  behavior: HitTestBehavior.translucent,
  child: MaterialApp(...),
);

Listen to Events

// All events combined
SessionManager.instance.onEvent.listen((event) {
  print('Event: $event');
});

// Individual event streams
SessionManager.instance.onLogin.listen((token) => print('User logged in'));
SessionManager.instance.onLogout.listen((_) => print('User logged out'));
SessionManager.instance.onSessionExpired.listen((_) => print('Session expired'));
SessionManager.instance.onTokenRefreshed.listen((token) => print('Token refreshed'));
SessionManager.instance.onTokenRefreshStarted.listen((_) => print('Refresh started'));
SessionManager.instance.onTokenRefreshFailed.listen((error) => print('Refresh failed: $error'));

// Auth state changes
SessionManager.instance.authStateChanges.listen((state) {
  switch (state) {
    case AuthState.authenticated:
      print('User is authenticated');
      break;
    case AuthState.unauthenticated:
      print('User is not authenticated');
      break;
    case AuthState.refreshing:
      print('Token is being refreshed');
      break;
  }
});

Cache Invalidation

For multi-isolate scenarios or external storage updates:

// Invalidate cache and re-read from storage
final freshToken = await SessionManager.instance.invalidateCache();

// Or with getSession
final freshSession = await SessionManager.instance.getSession(invalidateCache: true);

Reset SessionManager

For testing or complete reset:

await SessionManager.instance.reset();
// Now you can initialize it again with new configuration

Performance-First Design

• Lazy Initialization: Components like IdleController and LifecycleObserver are only created if configured.
• Mutex Locking: Ensures that even if 100 concurrent requests trigger a refresh, only one network call is made.
• In-Memory Cache: Tokens are cached in RAM after the first read from storage.
• No Polling: Idle detection is event-driven, no background polling.

Security Best Practices

1. Always use SecureStorageProvider for production apps
2. Never use SharedPreferencesProvider for sensitive tokens in production
3. Implement token revocation in your TokenProvider
4. Set appropriate idle timeouts for sensitive applications
5. Always handle token refresh failures gracefully in your UI

Migration Guide

From 1.1.0 to 1.2.0

• Breaking Changes: None - fully backward compatible
• New Features:
  • Added IdleListener widget for easy idle detection setup
  • Added TokenRefreshStartedEvent and TokenRefreshFailedEvent
  • Added AuthState.refreshing state
  • Added invalidateCache() method
  • Added reset() method
  • Added getSession(invalidateCache:) parameter
  • Added hasCachedToken getter
  • Added comprehensive exception types

Example

Check out the full example app in the repository.

❤️ Maintained By

GreenLogix — Flutter, Laravel & AI Development Agency
🌐 https://greelogix.com
📩 [e-mail]

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License

MIT