fix: method "keys" returns an immutable copy of the cache keys (#166)

Closes #165

Author: rafamizes

CHANGELOG.md

@@ -7,35 +7,44 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Method "keys" for listing all cache keys —
+ [152](https://github.com/dartoos-dev/json_cache/issues/152)
+
 ### Changed
 
-- update linting rules —
+- Mehtod "keys" returns an immutable copy of the underlying cache keys —
+ [165](https://github.com/dartoos-dev/json_cache/issues/152)
+
+- Update linting rules —
  [162](https://github.com/dartoos-dev/json_cache/issues/154).
 
-
 ## [3.0.2] - 2024-08-19
 
 ### Changed
 
-- Bump up dependencies —
+- Updated dependencies —
  [154](https://github.com/dartoos-dev/json_cache/issues/154).
 
 ### Fixed
 
-- Removed code warnings and upgraded dart SDK range and each dependency to latest resolvable version available - [148](https://github.com/dartoos-dev/json_cache/issues/148).
+- Remove code warnings and upgrade the dart SDK range. In addition, 
+ dependencies were updated to the latest resolvable version —
+ [148](https://github.com/dartoos-dev/json_cache/issues/148).
 
 ## [3.0.1] - 2023-08-10
 
 ### Fixed
 
-- removed unused package 'cross_local_storage' from pubspec —
+- Removed unused package 'cross_local_storage' from pubspec —
  [144](https://github.com/dartoos-dev/json_cache/issues/144). 
 
 ## [3.0.0] - 2023-08-10
 
 ### Removed
 
-- support for the 'cross_local_storage' package — **BREAKING CHANGE** —
+- Support for the 'cross_local_storage' package — **BREAKING CHANGE** —
  [140](https://github.com/dartoos-dev/json_cache/issues/140).
 
 ### Fixed

lib/src/json_cache.dart

@@ -28,8 +28,8 @@ abstract class JsonCache {
  /// Returns `true` if there is cached data at [key]; `false` otherwise.
  Future<bool> contains(String key);
 
- /// Lists all keys.
+ /// The cache keys.
  ///
- /// Returns an **unmodifiable** list of cache keys without duplicates.
+ /// Returns an **unmodifiable** list of all cache keys without duplicates.
  Future<UnmodifiableListView<String>> keys();
 }

lib/src/json_cache_fake.dart

@@ -55,6 +55,6 @@ class JsonCacheFake implements JsonCache {
 
  @override
  Future<UnmodifiableListView<String>> keys() async {
- return UnmodifiableListView(_memory.keys);
+ return UnmodifiableListView(List.unmodifiable(_memory.keys));
  }
 }

lib/src/json_cache_hive.dart

@@ -41,6 +41,8 @@ class JsonCacheHive implements JsonCache {
 
  @override
  Future<UnmodifiableListView<String>> keys() async {
- return UnmodifiableListView(_box.keys.map((k) => k as String));
+ return UnmodifiableListView(
+ _box.keys.map((k) => k as String).toList(growable: false),
+ );
  }
 }

lib/src/json_cache_mem.dart

@@ -161,7 +161,7 @@ class JsonCacheMem implements JsonCache {
  @override
  Future<UnmodifiableListView<String>> keys() {
  return _mutex.protectRead(() async {
- return UnmodifiableListView(_memory.keys);
+ return UnmodifiableListView(_memory.keys.toList(growable: false));
  });
  }
 }

lib/src/json_cache_safe_local_storage.dart

@@ -47,9 +47,8 @@ class JsonCacheSafeLocalStorage implements JsonCache {
 
  @override
  Future<UnmodifiableListView<String>> keys() async {
- final data = await _cachedData;
  return UnmodifiableListView(
- data.keys.map((k) => k as String),
+ (await _cachedData).keys.map((k) => k as String),
  );
  }
 

test/json_cache_fake_test.dart

@@ -2,7 +2,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:json_cache/json_cache.dart';
 
 void main() {
- group('JsonCacheFake', () {
+ group('JsonCacheFake:', () {
  const profKey = 'profile';
  const prefKey = 'preferences';
  const profData = <String, dynamic>{'id': 1, 'name': 'John Due'};
@@ -65,13 +65,24 @@ void main() {
  expect(await fake.contains(prefKey), false);
  expect(await fake.contains('a key'), false);
  });
- test('keys', () async {
- final fake = JsonCacheFake();
- // update data
- await fake.refresh(profKey, profData);
- await fake.refresh(prefKey, prefData);
-
- expect(await fake.keys(), [profKey, prefKey]);
+ group('method "keys"', () {
+ late JsonCacheFake fakeCache;
+ setUp(() async {
+ fakeCache = JsonCacheFake();
+ // update data
+ await fakeCache.refresh(profKey, profData);
+ await fakeCache.refresh(prefKey, prefData);
+ });
+ test('should return the inserted keys', () async {
+ expect(await fakeCache.keys(), [profKey, prefKey]);
+ });
+ test('should keep the returned keys immutable', () async {
+ final keys = await fakeCache.keys();
+ // This should not change the 'keys' variable.
+ await fakeCache
+ .refresh('info', {'This is very important information.': true});
+ expect(keys, [profKey, prefKey]);
+ });
  });
  group('remove', () {
  test('default ctor', () async {

test/json_cache_flutter_secure_storage_test.dart

@@ -4,7 +4,7 @@ import 'package:json_cache/json_cache.dart';
 import 'flutter_secure_storage_mock.dart';
 
 void main() {
- group('JsonCacheFlutterSecureStorage', () {
+ group('JsonCacheFlutterSecureStorage:', () {
  const profKey = 'profile';
  const prefKey = 'preferences';
  const profData = <String, dynamic>{'id': 1, 'name': 'John Due'};
@@ -50,15 +50,26 @@ void main() {
  await flutterSecureCache.remove(prefKey);
  expect(await flutterSecureCache.contains(prefKey), false);
  });
- test('keys', () async {
- final secStorageMock = FlutterSecureStorageMock();
- final JsonCacheFlutterSecureStorage flutterSecureCache =
- JsonCacheFlutterSecureStorage(secStorageMock);
- // update data
- await flutterSecureCache.refresh(profKey, profData);
- await flutterSecureCache.refresh(prefKey, prefData);
 
- expect(await flutterSecureCache.keys(), [profKey, prefKey]);
+ group('method "keys"', () {
+ late JsonCacheFlutterSecureStorage flutterSecureCache;
+ setUp(() async {
+ flutterSecureCache =
+ JsonCacheFlutterSecureStorage(FlutterSecureStorageMock());
+ // update data
+ await flutterSecureCache.refresh(profKey, profData);
+ await flutterSecureCache.refresh(prefKey, prefData);
+ });
+ test('should return the inserted keys', () async {
+ expect(await flutterSecureCache.keys(), [profKey, prefKey]);
+ });
+ test('should keep the returned keys immutable', () async {
+ final keys = await flutterSecureCache.keys();
+ // This should not change the 'keys' variable.
+ await flutterSecureCache
+ .refresh('info', {'This is very important information.': true});
+ expect(keys, [profKey, prefKey]);
+ });
  });
  test('remove', () async {
  final secStorageMock = FlutterSecureStorageMock();

test/json_cache_hive_test.dart

@@ -10,7 +10,7 @@ void main() {
  tearDown(() async {
  await tearDownTestHive();
  });
- group('JsonCacheHive', () {
+ group('JsonCacheHive:', () {
  const profKey = 'profile';
  const prefKey = 'preferences';
  const profData = <String, dynamic>{'id': 1, 'name': 'John Due'};
@@ -47,15 +47,25 @@ void main() {
  await hiveCache.remove(prefKey);
  expect(await hiveCache.contains(prefKey), false);
  });
-
- test('keys', () async {
- final box = await Hive.openBox<String>('test-contains-method');
- final JsonCacheHive hiveCache = JsonCacheHive(box);
- // update data
- await hiveCache.refresh(profKey, profData);
- await hiveCache.refresh(prefKey, prefData);
-
- expect(await hiveCache.keys(), [prefKey, profKey]);
+ group('method "keys"', () {
+ late JsonCacheHive hiveCache;
+ setUp(() async {
+ final box = await Hive.openBox<String>('test-keys-method');
+ hiveCache = JsonCacheHive(box);
+ // update data
+ await hiveCache.refresh(profKey, profData);
+ await hiveCache.refresh(prefKey, prefData);
+ });
+ test('should return the inserted keys', () async {
+ expect(await hiveCache.keys(), [prefKey, profKey]);
+ });
+ test('should keep the returned keys immutable', () async {
+ final keys = await hiveCache.keys();
+ // This should not change the 'keys' variable.
+ await hiveCache
+ .refresh('info', {'This is very important information.': true});
+ expect(keys, [prefKey, profKey]);
+ });
  });
  test('remove', () async {
  final box = await Hive.openBox<String>('test-remove');

test/json_cache_hollow_test.dart

@@ -2,7 +2,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:json_cache/json_cache.dart';
 
 void main() {
- group('JsonCacheHollow', () {
+ group('JsonCacheHollow:', () {
  const profKey = 'profile';
  const prefKey = 'preferences';
  const profData = <String, dynamic>{'id': 1, 'name': 'John Due'};
@@ -36,11 +36,17 @@ void main() {
  expect(await fake.contains('a key'), false);
  });
  test('keys', () async {
- const fake = JsonCacheHollow();
- await fake.refresh(profKey, profData);
- await fake.refresh(prefKey, prefData);
+ const hollowCache = JsonCacheHollow();
+ await hollowCache.refresh(profKey, profData);
+ await hollowCache.refresh(prefKey, prefData);
+
+ final keys = await hollowCache.keys();
+ expect(keys, const []);
 
- expect(await fake.keys(), const []);
+ // This should not change the 'keys' variable.
+ await hollowCache
+ .refresh('info', {'This is very important information.': true});
+ expect(keys, const []);
  });
  test('remove', () async {
  const JsonCacheHollow hollowCache = JsonCacheHollow();