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Real-time Sync (MQTT)

Real-time synchronization menggunakan MQTT

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🎯 Overview

MQTT adalah salah satu fitur utama dalam MStore Mobile yang menyediakan fungsionalitas untuk real-time synchronization menggunakan mqtt.

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📋 Features

  • ✅ Real-time inventory updates
  • ✅ Transaction notifications
  • ✅ System announcements
  • ✅ Auto-reconnect
  • ✅ Topic subscription management
  • ✅ Message queuing

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🏗️ Architecture

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BLoC Implementation

BLoC: MqttBloc 
// Events
abstract class MQTTEvent extends Equatable {}

class LoadMQTT extends MQTTEvent {}
class CreateMQTT extends MQTTEvent {}
class UpdateMQTT extends MQTTEvent {}
class DeleteMQTT extends MQTTEvent {}

// States
abstract class MQTTState extends Equatable {}

class MQTTInitial extends MQTTState {}
class MQTTLoading extends MQTTState {}
class MQTTLoaded extends MQTTState {}
class MQTTError extends MQTTState {}

// BLoC
class MQTTBloc extends Bloc<MQTTEvent, MQTTState> {
  final MQTTRepository _repository;
  
  MQTTBloc({required MQTTRepository repository})
      : _repository = repository,
        super(MQTTInitial()) {
    on<LoadMQTT>(_onLoad);
    on<CreateMQTT>(_onCreate);
    on<UpdateMQTT>(_onUpdate);
    on<DeleteMQTT>(_onDelete);
  }
  
  Future<void> _onLoad(
    LoadMQTT event,
    Emitter<MQTTState> emit,
  ) async {
    emit(MQTTLoading());
    
    final result = await _repository.getMQTTs();
    
    result.fold(
      (failure) => emit(MQTTError(failure.message)),
      (data) => emit(MQTTLoaded(data)),
    );
  }
}

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Repository Pattern

abstract class MQTTRepository {
  Future<Either<Failure, List<MQTT>>> getMQTTs();
  Future<Either<Failure, MQTT>> getMQTTById(String id);
  Future<Either<Failure, MQTT>> createMQTT(MQTT data);
  Future<Either<Failure, MQTT>> updateMQTT(String id, MQTT data);
  Future<Either<Failure, void>> deleteMQTT(String id);
}

class MQTTRepositoryImpl implements MQTTRepository {
  final MQTTApi _api;
  final MQTTLocalRepository _localRepo;
  
  @override
  Future<Either<Failure, List<MQTT>>> getMQTTs() async {
    try {
      // Try local first (offline-first)
      final local = await _localRepo.getMQTTs();
      
      // Sync with API in background
      final result = await _api.getMQTTs();
      result.fold(
        (failure) => null,
        (data) => _localRepo.saveMQTTs(data),
      );
      
      return Right(local.isNotEmpty ? local : result.getOrElse(() => []));
    } catch (e) {
      return Left(UnexpectedFailure(e.toString()));
    }
  }
}

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📡 API Integration

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Endpoints

  • MQTT Broker

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Request/Response Examples

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Get List

GET MQTT Broker
Authorization: Bearer {access_token}
Response: 
{
  "success": true,
  "data": [
    {
      "id": "123",
      "name": "Example",
      "created_at": "2024-10-14T10:00:00Z"
    }
  ],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 100
  }
}

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💾 Local Database (Isar)

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Schema

  • All collections
@collection
class MQTTLocal {
  Id id = Isar.autoIncrement;
  
  @Index()
  String? mqttId;
  
  String? name;
  DateTime? createdAt;
  DateTime? updatedAt;
  DateTime? syncedAt;
  
  bool? isSynced;
  bool? isDeleted;
}

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Queries

// Get all
final items = await isar.mqttLocals.where().findAll();

// Get by ID
final item = await isar.mqttLocals
    .filter()
    .mqttIdEqualTo(id)
    .findFirst();

// Search
final results = await isar.mqttLocals
    .filter()
    .nameContains(query, caseSensitive: false)
    .findAll();

// Get unsynced
final unsynced = await isar.mqttLocals
    .filter()
    .isSyncedEqualTo(false)
    .findAll();

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🔄 Offline-First Strategy

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Write Operations

  1. Save to local Isar immediately
  2. Show success to user
  3. Add to sync queue
  4. Background sync when online
  5. Update with server response

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Read Operations

  1. Read from local Isar (fast)
  2. Show to user immediately
  3. Background fetch from API
  4. Update local cache if changed
  5. Notify UI if data updated

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Conflict Resolution

  • Strategy: Last-write-wins
  • Timestamp: Server timestamp as source of truth
  • Logging: All conflicts logged for audit

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🎨 UI Components

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Main Screen

class MQTTPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (context) => getIt<MQTTBloc>()..add(LoadMQTT()),
      child: Scaffold(
        appBar: AppBar(title: Text('Real-time Sync (MQTT)')),
        body: BlocBuilder<MQTTBloc, MQTTState>(
          builder: (context, state) {
            if (state is MQTTLoading) {
              return Center(child: CircularProgressIndicator());
            }
            
            if (state is MQTTError) {
              return ErrorWidget(message: state.message);
            }
            
            if (state is MQTTLoaded) {
              return MQTTListView(items: state.items);
            }
            
            return SizedBox.shrink();
          },
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => _navigateToCreate(context),
          child: Icon(Icons.add),
        ),
      ),
    );
  }
}

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🧪 Testing

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Unit Tests

void main() {
  group('MQTTBloc', () {
    late MQTTBloc bloc;
    late MockMQTTRepository mockRepository;

    setUp(() {
      mockRepository = MockMQTTRepository();
      bloc = MQTTBloc(repository: mockRepository);
    });

    tearDown(() {
      bloc.close();
    });

    test('initial state is MQTTInitial', () {
      expect(bloc.state, equals(MQTTInitial()));
    });

    blocTest<MQTTBloc, MQTTState>(
      'emits [Loading, Loaded] when Load succeeds',
      build: () {
        when(() => mockRepository.getMQTTs()).thenAnswer(
          (_) async => Right([MQTT(id: '1', name: 'Test')]),
        );
        return bloc;
      },
      act: (bloc) => bloc.add(LoadMQTT()),
      expect: () => [
        MQTTLoading(),
        isA<MQTTLoaded>(),
      ],
    );
  });
}

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📊 Performance Considerations

  • Lazy Loading: Load data on demand
  • Pagination: Implement pagination for large datasets
  • Caching: Cache frequently accessed data
  • Indexing: Use Isar indexes for fast queries
  • Background Sync: Sync in background to avoid blocking UI

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🔐 Security

  • Authorization: Check user permissions before operations
  • Data Encryption: Sensitive data encrypted in Isar
  • Input Validation: Validate all user inputs
  • Audit Trail: Log all operations for audit

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📱 Platform-Specific

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iOS

  • Use Cupertino widgets
  • Follow iOS HIG
  • Handle safe area insets

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Android

  • Use Material widgets
  • Follow Material Design
  • Handle back button
Last Updated: October 14, 2024
Status: ✅ Production Ready