feat: JsonCacheSafeLocalStorage class

Author: Kinpert

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- JsonCacheSafeLocalStorage: an implementation on top of the safe_local_storage package - [124](https://github.com/dartoos-dev/json_cache/issues/124).
+
 ## [2.0.0] - 2023-03-22
 
 ### Changed

lib/src/json_cache_safe_local_storage.dart

@@ -0,0 +1,44 @@
+// ignore_for_file: avoid_dynamic_calls
+
+import 'package:json_cache/json_cache.dart';
+import 'package:safe_local_storage/safe_local_storage.dart';
+
+/// Implementation on top of the SafeLocalStorage package.
+///
+/// See: [Safe local storage](https://pub.dev/packages/safe_local_storage)
+class JsonCacheSafeLocalStorage implements JsonCache {
+  /// Encapsulates a [SafeLocalStorage] instance.
+  const JsonCacheSafeLocalStorage(this._localStorage);
+
+  final SafeLocalStorage _localStorage;
+
+  @override
+  Future<void> clear() async {
+    await _localStorage.delete();
+  }
+
+  @override
+  Future<bool> contains(String key) async {
+    final item = await _localStorage.read();
+    return item[key] != null;
+  }
+
+  @override
+  Future<void> refresh(String key, Map<String, dynamic> value) async {
+    final data = {key: value};
+    await _localStorage.write(data);
+  }
+
+  @override
+  Future<void> remove(String key) async {
+    final data = await _localStorage.read() as Map<String, dynamic>;
+    data.removeWhere((keyMap, valueMap) => keyMap == key);
+    await _localStorage.write(data);
+  }
+
+  @override
+  Future<Map<String, dynamic>?> value(String key) async {
+    final data = await _localStorage.read();
+    return data[key] == null ? null : data[key] as Map<String, dynamic>;
+  }
+}

pubspec.lock

@@ -432,6 +432,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.3"
+  safe_local_storage:
+    dependency: "direct main"
+    description:
+      name: safe_local_storage
+      sha256: "7ca14be87040e6badfcdb9c71e963846c4e7d827dbc9f62cab7496497352f8d8"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.0"
   shared_preferences:
     dependency: "direct main"
     description:
@@ -581,6 +589,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.2.0"
+  synchronized:
+    dependency: transitive
+    description:
+      name: synchronized
+      sha256: "33b31b6beb98100bf9add464a36a8dd03eb10c7a8cf15aeec535e9b054aaf04b"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.1"
   term_glyph:
     dependency: transitive
     description:
@@ -686,5 +702,5 @@ packages:
     source: hosted
     version: "3.1.1"
 sdks:
-  dart: ">=2.18.0 <3.0.0"
+  dart: ">=2.18.0 <4.0.0"
   flutter: ">=3.0.0"

pubspec.yaml

@@ -16,6 +16,7 @@ dependencies:
   hive: ^2.2.3
   localstorage: ^4.0.1+2
   mutex: ^3.0.1
+  safe_local_storage: ^1.0.0
   shared_preferences: ^2.0.18
 
 dev_dependencies:

test/json_cache_safe_local_storage_test.dart

@@ -0,0 +1,101 @@
+import 'dart:io';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:json_cache/src/json_cache_safe_local_storage.dart';
+import 'package:safe_local_storage/safe_local_storage.dart';
+
+void main() {
+  // Group of elements to 'mock' the temporary directory and file.
+  late Directory tempDir;
+  late File tempFile;
+
+  late SafeLocalStorage storage;
+
+  late JsonCacheSafeLocalStorage jsonCacheSafeLocalStorage;
+
+  // Profile data
+  const profKey = 'profile';
+  const profData = {
+    'name': 'John Doe',
+    'age': 23,
+    'email': 'johndoe@example.com',
+  };
+
+  // App preferences data
+  const prefKey = 'preferences';
+  const prefData = {
+    'theme': 'light',
+    'notifications': {'enabled': true}
+  };
+
+  setUp(
+    () async {
+      tempDir = Directory.systemTemp;
+      tempFile = File('${tempDir.path}/temp_file.json');
+      storage = SafeLocalStorage(tempFile.path);
+      jsonCacheSafeLocalStorage = JsonCacheSafeLocalStorage(storage);
+    },
+  );
+
+  group(
+    'JsonCacheSafeLocalStorage',
+    () {
+      test(
+        'refresh, value, clear, refresh',
+        () async {
+          await jsonCacheSafeLocalStorage.refresh(profKey, profData);
+
+          final data = await jsonCacheSafeLocalStorage.value(profKey);
+          expect(data, profData);
+          await jsonCacheSafeLocalStorage.clear();
+
+          final cleanCache = await jsonCacheSafeLocalStorage.value(profKey);
+          expect(cleanCache, isNull);
+        },
+      );
+
+      test(
+        'contains',
+        () async {
+          // Adding content on cache. Each 'refresh' method overrides the last one.
+          await jsonCacheSafeLocalStorage.refresh(profKey, profData);
+          await jsonCacheSafeLocalStorage.refresh(prefKey, prefData);
+
+          // Returning true if the last content exists on cache based on 'prefKey'.
+          expect(await jsonCacheSafeLocalStorage.contains(prefKey), true);
+          expect(await jsonCacheSafeLocalStorage.contains(profKey), false);
+
+          await jsonCacheSafeLocalStorage.refresh(profKey, profData);
+          // Returning true if the last content exists on cache based on 'profKey'.
+          expect(await jsonCacheSafeLocalStorage.contains(profKey), true);
+          expect(await jsonCacheSafeLocalStorage.contains(prefKey), false);
+
+          // Test for keys that doesn't exist
+          expect(await jsonCacheSafeLocalStorage.contains('generickey'), false);
+          expect(await jsonCacheSafeLocalStorage.contains('PROFKEY'), false);
+          expect(await jsonCacheSafeLocalStorage.contains('PREFKEY'), false);
+        },
+      );
+
+      test(
+        'remove',
+        () async {
+          await jsonCacheSafeLocalStorage.refresh(profKey, profData);
+
+          final recoveredData = await jsonCacheSafeLocalStorage.value(profKey);
+          expect(recoveredData, profData);
+
+          await jsonCacheSafeLocalStorage.remove(profKey);
+          final cleanCache = await jsonCacheSafeLocalStorage.value(profKey);
+          expect(cleanCache, isNull);
+        },
+      );
+    },
+  );
+
+  tearDown(
+    () async {
+      await storage.delete();
+      await tempDir.delete_();
+    },
+  );
+}