OfflineSync

OfflineSync is a Flutter package that provides offline-first data management and synchronization. It ensures smooth functionality even without an internet connection and syncs data once connectivity is restored.

Features

Local data storage and retrieval
Automatic synchronization with server when online
Conflict resolution
Encryption of sensitive data
Batch syncing for improved performance
Error handling and retry mechanisms

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  offline_sync: ^0.0.1

Usage

Initialization

First, initialize the OfflineSync instance in your app:

import 'package:offline_sync/offline_sync.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  final offlineSync = OfflineSync();
  await offlineSync.initialize();
  runApp(MyApp());
}

Setting Custom API Endpoint

Set a custom endpoint for your specific server:

final offlineSync = OfflineSync();
offlineSync.setApiEndpoint('https://your-custom-api.com');

Saving Data

To save data locally and queue it for syncing:

final offlineSync = OfflineSync();
await offlineSync.saveLocalData('user_1', {
  'name': 'John Doe',
  'email': 'john@example.com',
  'age': 30,
});

Reading Data

To read locally stored data:

final userData = await offlineSync.readLocalData('user_1');
if (userData != null) {
  print('User name: ${userData['name']}');
} else {
  print('User not found');
}

Syncing with Server

The package automatically syncs data when an internet connection is available. However, you can manually trigger a sync:

try {
  await offlineSync.updateFromServer();
  print('Data updated from server successfully');
} catch (e) {
  print('Failed to update from server: $e');
}

Handling Authentication

Set the authentication token for API requests:

await offlineSync.setAuthToken('your_auth_token_here');

Advanced Usage:

Conflict Resolution

The package includes basic conflict resolution. You can customize this by extending the OfflineSync class:

class CustomOfflineSync extends OfflineSync {
  @override
  Future<Map<String, dynamic>> resolveConflict(
    String id, 
    Map<String, dynamic> localData, 
    Map<String, dynamic> serverData
  ) async {
    // Implement your custom conflict resolution strategy here
    // This example prefers local changes
    final resolvedData = Map<String, dynamic>.from(serverData);
    localData.forEach((key, value) {
      if (value != serverData[key]) {
        resolvedData[key] = value;
      }
    });
    return resolvedData;
  }
}

Batch Processing

The package processes sync queue in batches. You can adjust the batch size:

class CustomOfflineSync extends OfflineSync {
  @override
  int get batchSize => 100; // Default is 50
}

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Joshuaerinosho / offline_sync