feat: create JsonCacheEncPrefs class (#45)

* feat: create JsonCacheEncPrefs class

Closes #30

* test: append the '_test' prefix to the test file of JsonCacheEncPref.

Author: rafamizes

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- JsonCacheEncPrefs: an implementation on top of the
+  [encrypted_shared_preferences](https://pub.dev/packages/encrypted_shared_preferences)
+  package — [30](https://github.com/dartoos-dev/json_cache/issues/30).
+
 ## [0.3.2] - 2021-08-25
 
 ### Changed
@@ -17,7 +23,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- JsonCacheCrossLocalStorage: implementation on top of the cross_local_storage
+- JsonCacheCrossLocalStorage: an implementation on top of the cross_local_storage
   package — [32](https://github.com/dartoos-dev/json_cache/issues/32).
 
 ### Changed
@@ -47,7 +53,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- JsonCacheLocalStorage: implementation on top of the localstorage package —
+- JsonCacheLocalStorage: an implementation on top of the localstorage package —
   [29](https://github.com/dartoos-dev/json_cache/issues/29).
 
 ### Added
@@ -58,7 +64,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- JsonCachePrefs: implementation on top of the shared_preferences package —
+- JsonCachePrefs: an implementation on top of the shared_preferences package —
   [26](https://github.com/dartoos-dev/json_cache/issues/26).
 
 ### Changed

README.md

@@ -24,6 +24,7 @@ Rultor.com](https://www.rultor.com/b/dartoos-dev/json_cache)](https://www.rultor
 - [Implementations](#implementations)
   - [JsonCacheMem — Thread-safe In-memory cache](#jsoncachemem)
   - [JsonCachePrefs — SharedPreferences](#jsoncacheprefs)
+  - [JsonCacheEncPrefs — EncryptedSharedPreferences](#jsoncacheencprefs)
   - [JsonCacheLocalStorage — LocalStorage](#jsoncachelocalstorage)
   - [JsonCacheCrossLocalStorage — CrossLocalStorage](#jsoncachecrosslocalstorage)
 - [Demo application](#demo-application)
@@ -180,6 +181,20 @@ is an implementation on top of the
   …
 ```
 
+### JsonCacheEncPrefs
+
+[JsonCacheEncPrefs](https://pub.dev/documentation/json_cache/latest/json_cache/JsonCacheEncPrefs-class.html)
+is an implementation on top of the
+[encrypted_shared_preferences](https://pub.dev/packages/encrypted_shared_preferences)
+package.
+
+```dart
+  …
+  final encPrefs = EncryptedSharedPreferences();
+  final JsonCache jsonCache = JsonCacheMem(JsonCacheEncPrefs(encPrefs));
+  …
+```
+
 ### JsonCacheLocalStorage
 
 [JsonCacheLocalStorage](https://pub.dev/documentation/json_cache/latest/json_cache/JsonCacheLocalStorage-class.html)

lib/json_cache.dart

@@ -3,6 +3,7 @@ library json_cache;
 
 export 'src/json_cache.dart';
 export 'src/json_cache_cross_local_storage.dart';
+export 'src/json_cache_enc_prefs.dart';
 export 'src/json_cache_fake.dart';
 export 'src/json_cache_hollow.dart';
 export 'src/json_cache_local_storage.dart';

lib/src/json_cache_enc_prefs.dart

@@ -0,0 +1,43 @@
+import 'dart:convert';
+
+import 'package:encrypted_shared_preferences/encrypted_shared_preferences.dart';
+
+import 'json_cache.dart';
+
+/// Shared Preferences as encrypted values.
+///
+/// See also:
+/// -
+/// [encrypted_shared_preferences](https://pub.dev/packages/encrypted_shared_preferences)
+class JsonCacheEncPrefs implements JsonCache {
+  /// [_encPrefs] an [EncryptedSharedPreferences] instance.
+  JsonCacheEncPrefs(this._encPrefs);
+
+  // The encrypted preferences file object.
+  final EncryptedSharedPreferences _encPrefs;
+
+  @override
+  Future<void> clear() async {
+    await _encPrefs.clear();
+  }
+
+  @override
+  Future<void> refresh(String key, Map<String, dynamic> value) async {
+    await _encPrefs.setString(key, json.encode(value));
+  }
+
+  @override
+  Future<void> remove(String key) async {
+    await (await _encPrefs.getInstance()).remove(key);
+  }
+
+  @override
+  Future<Map<String, dynamic>?> value(String key) async {
+    final shrPrefs = await _encPrefs.getInstance();
+    if (shrPrefs.containsKey(key)) {
+      return json.decode(await _encPrefs.getString(key))
+          as Map<String, dynamic>;
+    }
+    return null;
+  }
+}

pubspec.lock

@@ -1,13 +1,27 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  args:
+    dependency: transitive
+    description:
+      name: args
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.0"
+  asn1lib:
+    dependency: transitive
+    description:
+      name: asn1lib
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.2"
   async:
     dependency: transitive
     description:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.6.1"
+    version: "2.8.1"
   boolean_selector:
     dependency: transitive
     description:
@@ -28,7 +42,7 @@ packages:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0"
+    version: "1.3.1"
   clock:
     dependency: transitive
     description:
@@ -43,13 +57,41 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.15.0"
+  convert:
+    dependency: transitive
+    description:
+      name: convert
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.1"
   cross_local_storage:
     dependency: "direct main"
     description:
       name: cross_local_storage
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.1"
+  crypto:
+    dependency: transitive
+    description:
+      name: crypto
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.1"
+  encrypt:
+    dependency: transitive
+    description:
+      name: encrypt
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.0.1"
+  encrypted_shared_preferences:
+    dependency: "direct main"
+    description:
+      name: encrypted_shared_preferences
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   fake_async:
     dependency: transitive
     description:
@@ -120,7 +162,7 @@ packages:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0"
+    version: "1.7.0"
   mutex:
     dependency: "direct main"
     description:
@@ -184,6 +226,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.1"
+  pointycastle:
+    dependency: transitive
+    description:
+      name: pointycastle
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.3.1"
   process:
     dependency: transitive
     description:
@@ -279,7 +328,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.0"
+    version: "0.4.2"
   typed_data:
     dependency: transitive
     description:

pubspec.yaml

@@ -10,6 +10,7 @@ environment:
 
 dependencies:
   cross_local_storage: ^2.0.1
+  encrypted_shared_preferences: ^2.0.0
   flutter:
     sdk: flutter
   localstorage: ^4.0.0+1

test/json_cache_enc_prefs_test.dart

@@ -0,0 +1,49 @@
+import 'package:encrypted_shared_preferences/encrypted_shared_preferences.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:json_cache/json_cache.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+void main() {
+  SharedPreferences.setMockInitialValues({});
+  group('JsonCachePrefs', () {
+    test('clear, value, refresh', () async {
+      const profKey = 'profile';
+      const profData = <String, Object>{'id': 1, 'name': 'John Due'};
+      final JsonCacheEncPrefs encPrefsCache =
+          JsonCacheEncPrefs(EncryptedSharedPreferences());
+      await encPrefsCache.refresh(profKey, profData);
+      var prof = await encPrefsCache.value(profKey);
+      expect(prof, profData);
+      await encPrefsCache.clear();
+      prof = await encPrefsCache.value(profKey);
+      expect(prof, isNull);
+    });
+
+    test('remove', () async {
+      const profKey = 'profile';
+      const prefKey = 'preferences';
+      final profData = <String, Object>{'id': 1, 'name': 'John Due'};
+      final prefData = <String, Object>{
+        'theme': 'dark',
+        'notifications': {'enabled': true}
+      };
+      final JsonCacheEncPrefs encPrefsCache =
+          JsonCacheEncPrefs(EncryptedSharedPreferences());
+      await encPrefsCache.refresh(profKey, profData);
+      await encPrefsCache.refresh(prefKey, prefData);
+
+      var prof = await encPrefsCache.value(profKey);
+      expect(prof, profData);
+
+      await encPrefsCache.remove(profKey);
+      prof = await encPrefsCache.value(profKey);
+      expect(prof, isNull);
+
+      var pref = await encPrefsCache.value(prefKey);
+      expect(pref, prefData);
+      await encPrefsCache.remove(prefKey);
+      pref = await encPrefsCache.value(prefKey);
+      expect(pref, isNull);
+    });
+  });
+}

test/json_cache_prefs_test.dart

@@ -5,7 +5,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 void main() {
   SharedPreferences.setMockInitialValues({});
   group('JsonCachePrefs', () {
-    test('clear, recover and refresh', () async {
+    test('clear, value, refresh', () async {
       const profKey = 'profile';
       const profData = <String, Object>{'id': 1, 'name': 'John Due'};
       final JsonCachePrefs prefsCache =