riverpod_cache_engine 1.0.0

A powerful, zero-boilerplate caching library for Riverpod with background garbage collection, auto-refresh mechanisms, and in-memory/persistent storage support.

example/lib/main.dart

import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:riverpod_cache_engine/riverpod_cache_engine.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  // Initialize the library: Zero config needed! It will use InMemoryCacheStore by default.
  await RiverpodCache.initialize(cleanupInterval: const Duration(seconds: 10));

  runApp(const ProviderScope(child: MyApp()));
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(debugShowCheckedModeBanner: false, home: MyHome());
  }
}

// ==========================================
// Example using the new Extensions Architecture
// ==========================================

/// A simple data model for testing
class UserProfile {
  final String name;
  final int age;

  UserProfile({required this.name, required this.age});

  Map<String, dynamic> toJson() => {'name': name, 'age': age};

  factory UserProfile.fromJson(Map<String, dynamic> json) {
    return UserProfile(name: json['name'] as String, age: json['age'] as int);
  }
}

/// A Notifier that manages the User state
class UserNotifier extends Notifier<UserProfile?> {
  @override
  UserProfile? build() {
    loadUserData();
    return null;
  }

  /// Function to load data from cache or an external source (API)
  Future<void> loadUserData() async {
    // 1. Read from the cache
    // Thanks to onNull and onExpired, the library will fetch the data whether it's missing or expired!
    final cachedMap = await caches.read(
      'user_profile_key',
      options: CacheOptions(
        ttl: const Duration(seconds: 5),
        onExpired: () async {
          debugPrint('Fetching user update from server (onExpired)...');
          await Future.delayed(const Duration(seconds: 1));
          return UserProfile(name: 'Updated Ahmed', age: 29).toJson();
        },
        onNull: () async {
          debugPrint(
            'Cache not found! Fetching for the first time (onNull)...',
          );
          await Future.delayed(const Duration(seconds: 1));
          return UserProfile(name: 'New Ahmed', age: 28).toJson();
        },
      ),
    );

    if (cachedMap != null) {
      // 2. Update state
      state = UserProfile.fromJson(cachedMap);
      debugPrint('Screen updated from cache!');
    }
  }

  /// Function to clear the cache manually
  Future<void> clearCache() async {
    await caches.delete('user_profile_key');
    state = null;
    debugPrint('Cache cleared!');
  }

  List<String> list = ['Ahmed', 'Khalid', 'Saeed'];

  void setRandomName() async {
    int a = Random().nextInt(list.length);
    await caches.write(
      'randomName',
      {'randomName': list[a]},
      options: CacheOptions(
        ttl: const Duration(seconds: 10),
        onExpired: () async {
          int aa = Random().nextInt(list.length);
          final result = {'randomName': list[aa]};
          return result;
        },
      ),
    );
  }

  void getLastName() async {
    final name = await caches.read('randomName');
    print(name);
  }
}

// Provide the Notifier
final userProvider = NotifierProvider<UserNotifier, UserProfile?>(
  () => UserNotifier(),
);

class MyHome extends ConsumerWidget {
  const MyHome({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final userState = ref.watch(userProvider);
    final userNotifier = ref.read(userProvider.notifier);

    return Scaffold(
      appBar: AppBar(title: const Text('Riverpod Cache Extension')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            if (userState == null)
              const Text('No data currently available')
            else
              Text(
                'Name: ${userState.name} | Age: ${userState.age}',
                style: const TextStyle(fontSize: 20),
              ),

            const SizedBox(height: 20),
            ElevatedButton(
              onPressed: () => userNotifier.loadUserData(),
              child: const Text('Load Data (Cache or Network)'),
            ),
            const SizedBox(height: 10),
            ElevatedButton(
              onPressed: () => userNotifier.clearCache(),
              style: ElevatedButton.styleFrom(
                backgroundColor: Colors.redAccent,
              ),
              child: const Text('Clear Cache'),
            ),
            ElevatedButton(
              onPressed: () => userNotifier.setRandomName(),
              style: ElevatedButton.styleFrom(
                backgroundColor: Colors.blueAccent,
              ),
              child: const Text('Set Random Name'),
            ),
            ElevatedButton(
              onPressed: () => userNotifier.getLastName(),
              style: ElevatedButton.styleFrom(backgroundColor: Colors.green),
              child: const Text('Get Random Name'),
            ),
          ],
        ),
      ),
    );
  }
}