syncache_hive

Hive storage backend for Syncache - cross-platform persistent caching.

Features

  • Persistent storage using Hive
  • Cross-platform support (iOS, Android, Web, Desktop, Pure Dart)
  • Full support for tag-based cache invalidation
  • Pattern-based key matching and deletion
  • Automatic serialization via JSON
  • Atomic operations - each entry (data + tags) is stored as a single unit

Installation

Add syncache_hive to your pubspec.yaml:

dependencies:
  syncache: ^0.1.0
  syncache_hive: ^0.1.0
  hive: ^2.2.0

For Flutter apps, also add hive_flutter:

dependencies:
  hive_flutter: ^1.1.0

Usage

Basic Setup

import 'package:hive/hive.dart';
import 'package:syncache/syncache.dart';
import 'package:syncache_hive/syncache_hive.dart';

void main() async {
  // Initialize Hive (required once per app)
  Hive.init('path/to/hive');

  // Open a HiveStore with your data type
  final store = await HiveStore.open<User>(
    boxName: 'users',
    fromJson: User.fromJson,
    toJson: (user) => user.toJson(),
  );

  // Create a Syncache instance with the store
  final cache = Syncache<User>(store: store);

  // Use the cache
  final user = await cache.get(
    key: 'user:123',
    fetch: (req) => api.getUser('123'),
  );
}

Flutter Setup

import 'package:flutter/material.dart';
import 'package:hive_flutter/hive_flutter.dart';
import 'package:syncache/syncache.dart';
import 'package:syncache_hive/syncache_hive.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  // Initialize Hive for Flutter
  await Hive.initFlutter();

  final store = await HiveStore.open<User>(
    boxName: 'users',
    fromJson: User.fromJson,
    toJson: (user) => user.toJson(),
  );

  final cache = Syncache<User>(store: store);

  runApp(MyApp(cache: cache));
}

Using Tags

// Store with tags for grouped invalidation
await cache.get(
  key: 'calendar:events:2024-03',
  fetch: fetchEvents,
  tags: ['calendar', 'events', 'workspace:123'],
);

// Invalidate all entries with 'calendar' tag
await cache.invalidateTag('calendar');

Closing the Store

Remember to close the store when you're done:

await store.close();

API Reference

HiveStore

class HiveStore<T> implements TaggableStore<T> {
  /// Opens a HiveStore with the specified box name.
  static Future<HiveStore<T>> open<T>({
    required String boxName,
    required T Function(Map<String, dynamic>) fromJson,
    required Map<String, dynamic> Function(T) toJson,
  });

  /// Closes the store and releases resources.
  Future<void> close();
}

Inherited from TaggableStore

  • write(key, entry) - Store a value
  • writeWithTags(key, entry, tags) - Store a value with tags
  • read(key) - Retrieve a value
  • delete(key) - Delete a value
  • clear() - Clear all values
  • getTags(key) - Get tags for a key
  • getKeysByTag(tag) - Get all keys with a tag
  • deleteByTag(tag) - Delete all entries with a tag
  • deleteByTags(tags, {matchAll}) - Delete entries matching tags
  • getKeysByPattern(pattern) - Get keys matching a glob pattern
  • deleteByPattern(pattern) - Delete keys matching a glob pattern

Limitations

  • Key length: Hive limits keys to a maximum of 255 characters. Attempting to use longer keys will throw a HiveError.
  • Tag replacement: Unlike MemoryStore, calling write() on a key that already has tags will remove those tags. Use writeWithTags() to explicitly set tags.

Serialization

HiveStore requires fromJson and toJson functions to serialize your data type. This is because Hive stores data as maps internally.

class User {
  final String name;
  final String email;

  User({required this.name, required this.email});

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

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

License

MIT License - see LICENSE file for details.

Libraries

syncache_hive
Hive storage backend for Syncache.