flutter_network_state 1.0.1

Network-aware state management engine for Flutter. Offline queue, cache strategies, Dio interceptor, auto-sync, and Bloc-friendly sealed states.

flutter_network_state

A network-aware state management and request orchestration engine for Flutter.
Not just another connectivity checker.

---

What is this?

flutter_network_state is a decision engine that sits between your app and the network. It unifies:

• 🌐 Online/Offline detection — stream-based, always reactive
• 🎯 Smart request strategies — NetworkFirst, CacheFirst, CacheOnly, NetworkOnly
• 📦 In-memory caching — with TTL and pluggable storage
• 📋 Offline request queue — failed requests are queued and replayed automatically
• 🔄 Automatic sync — queue drains when connectivity is restored
• 🔌 Dio interceptor — drop-in auto-retry and offline queueing
• 🧩 State management ready — built-in support for Provider, Cubit, Bloc, and Riverpod
• 🔁 Retry policies — exponential, linear, constant backoff with jitter

Think of it as Dio + Bloc + Offline Sync + Connectivity in one clean abstraction.

---

Getting Started

Installation

dependencies:
  flutter_network_state: ^1.0.0

flutter pub get

Minimal Example

import 'package:flutter_network_state/flutter_network_state.dart';

final manager = NetworkManager();

// Listen to state changes
manager.stateStream.listen((state) {
  switch (state) {
    case Idle()    => print('Ready');
    case Loading() => print('Loading...');
    case Offline() => print('Offline (${state.queuedRequests} queued)');
    case Syncing() => print('Syncing ${(state.progress * 100).toStringAsFixed(0)}%');
    case Success() => print('Data: ${state.data}');
    case Error()   => print('Error: ${state.message}');
  }
});

// Make a request with strategy
final user = await manager.request(
  () => api.getUser(),
  cacheKey: 'user',
  strategy: CacheFirst(),
);

That's it. The manager handles connectivity detection, caching, offline queueing, and automatic sync — all behind that single request() call.

---

Core Concepts

Network States

All states are Dart 3 sealed classes — fully exhaustive in switch:

State	Description
Idle	No operation in progress
Loading	A request is executing
Offline	Device has no connectivity. Includes queuedRequests count
Syncing	Queue is being replayed after reconnect. Includes progress (0.0–1.0)
Success<T>	Request completed. Contains data and fromCache flag
Error	Request failed. Contains message, exception, and isRetryable

Request Strategies

Control how each request is resolved:

Strategy	Behavior
NetworkFirst()	Try network → fall back to cache on failure (default)
CacheFirst()	Try cache → fall back to network on miss or expiry
CacheOnly()	Only use cache — never hits the network
NetworkOnly()	Only use network — never reads or writes cache

// Cache-first with custom TTL
final config = await manager.request(
  () => api.getAppConfig(),
  cacheKey: 'app_config',
  strategy: CacheFirst(),
  cacheTtl: Duration(hours: 1),
);

// Network-only for mutations
await manager.request(
  () => api.updateProfile(data),
  strategy: NetworkOnly(),
);

---

State Management Integration

flutter_network_state ships with built-in support for the most popular Flutter state management solutions — without adding any of them as dependencies. Pick the one you use:

Provider (ChangeNotifier)

Use NetworkNotifier, a ready-made ChangeNotifier:

// Setup
ChangeNotifierProvider(
  create: (_) => NetworkNotifier(networkManager),
  child: MyApp(),
);

// In your widget
class UserPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final notifier = context.watch<NetworkNotifier>();

    return switch (notifier.state) {
      Idle()    => Text('Tap to load'),
      Loading() => CircularProgressIndicator(),
      Offline() => Text('Offline (${(notifier.state as Offline).queuedRequests} queued)'),
      Success() => Text('Hello, ${(notifier.state as Success).data}'),
      Error()   => Text('Error: ${(notifier.state as Error).message}'),
      _         => SizedBox.shrink(),
    };
  }
}

// Trigger a request
final notifier = context.read<NetworkNotifier>();
await notifier.request(
  () => api.getUser(),
  cacheKey: 'user',
  strategy: CacheFirst(),
);

Cubit (No flutter_bloc needed)

Use NetworkCubit, a lightweight Cubit-like base class:

class UserCubit extends NetworkCubit {
  UserCubit(NetworkManager manager) : super(manager);

  Future<void> loadUser() async {
    await executeRequest(
      () => api.getUser(),
      cacheKey: 'user',
      strategy: CacheFirst(),
    );
  }

  Future<void> updateProfile(Map<String, dynamic> data) async {
    await executeRequest(
      () => api.updateProfile(data),
      strategy: NetworkOnly(),
    );
  }
}

// Usage
final cubit = UserCubit(networkManager);

// Listen to state changes
cubit.stream.listen((state) {
  switch (state) {
    case Success<User>() => print('Got user: ${state.data.name}');
    case Loading()       => print('Loading...');
    case Offline()       => print('Offline');
    case Error()         => print('Error: ${state.message}');
    _                    => null;
  }
});

await cubit.loadUser();

// Don't forget to close
await cubit.close();

Bloc (flutter_bloc)

If you already use flutter_bloc, use the executeAndEmit() extension:

class UserCubit extends Cubit<NetworkState> {
  UserCubit(this._manager) : super(const Idle());
  final NetworkManager _manager;

  Future<void> loadUser() async {
    await _manager.executeAndEmit(
      () => api.getUser(),
      emit: emit,
      cacheKey: 'user',
      strategy: CacheFirst(),
    );
  }
}

// Or bind the global connectivity state stream
class ConnectivityCubit extends Cubit<NetworkState> {
  ConnectivityCubit(this._manager) : super(const Idle());
  final NetworkManager _manager;
  late final StreamSubscription _sub;

  void init() {
    _sub = _manager.bindToEmit(emit);
  }

  @override
  Future<void> close() {
    _sub.cancel();
    return super.close();
  }
}

Riverpod

Use NetworkStateNotifier with Riverpod providers:

// 1. Provide the NetworkManager
final networkManagerProvider = Provider<NetworkManager>((ref) {
  final manager = NetworkManager();
  ref.onDispose(() => manager.dispose());
  return manager;
});

// 2. Stream the global connectivity state
final networkStateProvider = StreamProvider<NetworkState>((ref) {
  return ref.watch(networkManagerProvider).stateStream;
});

// 3. Create feature-specific notifiers
final userProvider = Provider<NetworkStateNotifier>((ref) {
  final notifier = ref.watch(networkManagerProvider).createNotifier();
  ref.onDispose(() => notifier.dispose());
  return notifier;
});

// In your widget
class UserPage extends ConsumerWidget {
  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final userNotifier = ref.watch(userProvider);

    return switch (userNotifier.state) {
      Loading() => CircularProgressIndicator(),
      Success() => Text('${(userNotifier.state as Success).data}'),
      Offline() => Text('Offline'),
      Error()   => Text('Error'),
      _         => ElevatedButton(
        onPressed: () => ref.read(userProvider).execute(
          () => api.getUser(),
          cacheKey: 'user',
          strategy: CacheFirst(),
        ),
        child: Text('Load User'),
      ),
    };
  }
}

Stream Transformer (Any architecture)

Turn any Stream<T> into Stream<NetworkState>:

final stateStream = myDataStream.asNetworkStates();
// Each emission becomes Success<T>, errors become Error

---

Dio Integration

Drop the interceptor into any existing Dio instance:

final dio = Dio(BaseOptions(baseUrl: 'https://api.example.com'));

dio.interceptors.add(
  NetworkDioInterceptor(
    monitor: manager.monitor,
    queue: manager.queue,
    config: DioInterceptorConfig(
      retryPolicy: RetryPolicy(
        maxRetries: 3,
        backoff: ExponentialBackoff(baseDelay: Duration(seconds: 1)),
      ),
      queueWhenOffline: true,
      logRequests: true,
      logResponses: true,
    ),
  ),
);

The interceptor automatically:

• ✅ Retries transient failures (timeouts, 500s, 502s, 503s, 429s)
• ✅ Queues requests when the device is offline
• ✅ Replays queued requests when connectivity is restored

---

Retry Policies

Every retry policy supports configurable backoff:

// Exponential backoff with jitter (default)
RetryPolicy(
  maxRetries: 3,
  backoff: ExponentialBackoff(
    baseDelay: Duration(seconds: 1),
    maxDelay: Duration(seconds: 30),
    withJitter: true, // ±25% to prevent thundering herd
  ),
);

// Constant delay
RetryPolicy(
  maxRetries: 5,
  backoff: ConstantBackoff(duration: Duration(seconds: 2)),
);

// Linear backoff
RetryPolicy(
  maxRetries: 4,
  backoff: LinearBackoff(baseDelay: Duration(seconds: 1)),
);

// Disable retries
RetryPolicy.none;

Custom retry predicate:

RetryPolicy(
  maxRetries: 3,
  shouldRetry: (error, attempt) {
    return error is TimeoutException;
  },
);

---

Cache Management

Basic operations

// Store
manager.cache.set('key', myData, ttl: Duration(hours: 1));

// Retrieve (null if expired)
final data = manager.cache.get<MyModel>('key');

// Check existence (respects TTL)
manager.cache.has('key');

// Invalidate
manager.invalidateCache('key');

// Clear all
manager.clearCache();

Custom storage backend

Implement CacheStore to use Hive, Isar, SharedPreferences, or any persistence layer:

class HiveCacheStore implements CacheStore {
  final Box _box;
  HiveCacheStore(this._box);

  @override
  dynamic get(String key) => _box.get(key);
  @override
  void set(String key, dynamic value) => _box.put(key, value);
  @override
  void remove(String key) => _box.delete(key);
  @override
  void clear() => _box.clear();
  @override
  bool containsKey(String key) => _box.containsKey(key);
}

final manager = NetworkManager(
  cacheManager: CacheManager(store: HiveCacheStore(box)),
);

---

Offline Queue & Sync

Automatic flow

1. Request fails while offline → automatically queued
2. Device reconnects → SyncEngine drains the queue
3. State stream emits Syncing(progress) → UI shows progress
4. All done → state returns to Idle

Manual queue operations

// Enqueue manually
manager.queue.enqueue(
  QueuedRequest(
    id: 'update_profile',
    execute: () => api.updateProfile(data),
    retryPolicy: RetryPolicy(maxRetries: 5),
  ),
);

// Inspect
print('Pending: ${manager.queue.length}');

// Force sync
final results = await manager.syncNow();

// Clear
manager.clearQueue();

---

Logging

// Default — prints to console
final manager = NetworkManager();

// Silent
final manager = NetworkManager(logger: NetworkLogger.silent);

// Custom — forward to Crashlytics, Sentry, etc.
final manager = NetworkManager(
  logger: NetworkLogger.custom(
    (level, message) {
      FirebaseCrashlytics.instance.log('[$level] $message');
    },
    minLevel: LogLevel.warning,
  ),
);

---

Configuration

final manager = NetworkManager(
  config: NetworkManagerConfig(
    defaultStrategy: NetworkFirst(),
    defaultCacheTtl: Duration(minutes: 5),
    retryPolicy: RetryPolicy(maxRetries: 3),
    autoStart: true,
  ),
);

---

Architecture

lib/
 ├── core/
 │    ├── network_state.dart       ← Sealed state hierarchy
 │    ├── network_status.dart      ← Connectivity monitor
 │    ├── network_strategy.dart    ← Request strategies
 │    ├── retry_policy.dart        ← Backoff strategies
 │    └── logger.dart              ← Pluggable logger
 ├── manager/
 │    └── network_manager.dart     ← Central orchestrator
 ├── queue/
 │    └── request_queue.dart       ← Offline request queue
 ├── cache/
 │    └── cache_manager.dart       ← TTL cache
 ├── sync/
 │    └── sync_engine.dart         ← Auto-sync on reconnect
 ├── dio/
 │    └── dio_interceptor.dart     ← Dio interceptor
 ├── extensions/
 │    ├── bloc_extension.dart      ← Bloc helpers
 │    ├── cubit_extension.dart     ← Standalone Cubit base class
 │    ├── provider_extension.dart  ← ChangeNotifier for Provider
 │    └── riverpod_extension.dart  ← StateNotifier for Riverpod
 └── flutter_network_state.dart    ← Barrel export

Every sub-component can be injected individually for testing or customization.

---

Requirements

Requirement	Version
Dart SDK	>=3.0.0 <4.0.0
Flutter	>=3.10.0
Null safety	✅

Dependencies

Package	Purpose
connectivity_plus	Platform connectivity detection
dio	HTTP client integration
meta	Annotation utilities

Note: No dependency on provider, flutter_bloc, or riverpod. All state management integrations are built on plain Dart streams and Flutter SDK primitives.

---

Comparison

Feature	connectivity_plus	dio_cache_interceptor	flutter_network_state
Online/Offline detection	✅	❌	✅
Request strategies	❌	Partial	✅ 4 strategies
Cache with TTL	❌	✅	✅ + pluggable
Offline queue	❌	❌	✅
Auto sync on reconnect	❌	❌	✅
Retry with backoff	❌	❌	✅ 3 strategies
Dio interceptor	❌	✅	✅
Provider support	❌	❌	✅
Cubit support	❌	❌	✅
Bloc support	❌	❌	✅
Riverpod support	❌	❌	✅
Unified state stream	❌	❌	✅

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💖 Support

If this package helps you build better Flutter apps, consider supporting the development:

Your support helps keep this package maintained and up-to-date. Every contribution is greatly appreciated! 🙏

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License

MIT — see LICENSE for details.