kache_hive_ce

简体中文

The official restart-safe Hive CE persistence backend for Kache. It stores versioned byte envelopes and does not require Hive TypeAdapter classes for application models.

Installation

dart pub add kache_hive_ce

Flutter applications that call Hive.initFlutter should also declare and import hive_ce_flutter directly.

Quick start

import 'dart:convert';
import 'dart:typed_data';

import 'package:kache/kache.dart';
import 'package:kache_hive_ce/kache_hive_ce.dart';

final class User {
  const User(this.id, this.name);

  factory User.fromJson(Map<String, Object?> json) =>
      User(json['id']! as String, json['name']! as String);

  final String id;
  final String name;

  Map<String, Object?> toJson() => <String, Object?>{'id': id, 'name': name};
}

abstract interface class UserApi {
  Future<User> fetchUser(String id);
}

final class UserCache {
  const UserCache(this.client, this.query);

  final KacheClient client;
  final KacheQuery<User> query;
}

Future<UserCache> openUserCache(UserApi api, String userId) async {
  final store = await HiveCeKacheStore.open(boxName: 'app-cache');
  final binding = store.bind<User>(
    codecId: 'user-json',
    schema: 1,
    codec: HiveCeCodec<User>(
      encode: (user) =>
          Uint8List.fromList(utf8.encode(jsonEncode(user.toJson()))),
      decode: (bytes) =>
          User.fromJson(jsonDecode(utf8.decode(bytes)) as Map<String, Object?>),
    ),
  );
  final client = KacheClient(
    persistence: store,
    persistenceOwnership: KachePersistenceOwnership.owned,
  );
  final query = KacheQuery<User>.persisted(
    key: KacheKey('users', <Object?>[userId]),
    binding: binding,
    fetch: (_) => api.fetchUser(userId),
  );
  return UserCache(client, query);
}

Codec and schema

codecId identifies the model format and must remain stable. schema is a positive unsigned 32-bit version. Increasing the schema changes the binding fingerprint, so provide migrate(payload, fromSchema) to read older envelopes.

Migration returns typed data immediately. Kache then schedules lazy maintenance to rewrite the record with the current schema. A maintenance write failure remains visible in persistence state and events without hiding data.

Corruption and errors

Unknown envelopes, invalid metadata, codec mismatch, decode failures, and missing migrations are reported as KachePersistenceException with an exact operation and stage. Core recovery deletes the damaged record and continues as a cache miss according to policy.

Core lookup events report persistence cacheHit, cacheMiss, and cacheExpired outcomes without exposing encoded values or keys.

Encryption

Pass an application-owned HiveCipher to HiveCeKacheStore.open, or wrap an already-open encrypted Box<Object?> with HiveCeKacheStore.fromBox. Kache never stores or logs encryption keys.

Ownership

open uses reference-counted box leases. A box opened by Kache closes after the final lease; a box already opened elsewhere is borrowed. fromBox defaults to HiveCeBoxOwnership.borrowed; select owned only when the store must close that injected box.

Configure the store as an owned KacheClient backend when the client is the single lifecycle owner. Closing both layers is idempotent.

Compatibility

Component	Supported range
Dart	Dart >=3.5.0 <4.0.0
Flutter	Not required
Hive CE	>=2.19.3 <3.0.0

License

MIT