feat(#16): Allow POST methods to be cached

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 2.3.0
+- feat: `allowPostMethod` added to `CacheOptions`.
+
 ## 2.2.0
 - feat: Cache-Control: max-age as cache trigger added.
 - core: update README.md.

README.md

@@ -34,7 +34,7 @@ import 'package:dio_cache_interceptor/dio_cache_interceptor.dart';
 // Global options
 final options = const CacheOptions(
   // A default store is required for interceptor.
-  store: DbCacheStore(databasePath: 'a_path'),
+  store: MemCacheStore(),
   // Default.
   policy: CachePolicy.request,
   // Optional. Returns a cached response on error but for statuses 401 & 403.
@@ -43,6 +43,13 @@ final options = const CacheOptions(
   maxStale: const Duration(days: 7),
   // Default. Allows 3 cache sets and ease cleanup.
   priority: CachePriority.normal,
+  // Default. Body and headers encryption with your own algorithm.
+  cipher: null,
+  // Default. Key builder to retrieve requests.
+  keyBuilder: CacheOptions.defaultCacheKeyBuilder,
+  // Default. Allows to cache POST requests.
+  // Overriding [keyBuilder] is strongly recommended.
+  allowPostMethod: false,
 );
 
 // Add cache interceptor with global/default options

example/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Sat Jun 27 10:47:21 CEST 2020
+#Sat Apr 24 18:07:04 CEST 2021
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-all.zip

lib/src/dio_cache_interceptor.dart

@@ -14,6 +14,7 @@ import 'util/response_extension.dart';
 /// Cache interceptor
 class DioCacheInterceptor extends Interceptor {
   static const String _getMethodName = 'GET';
+  static const String _postMethodName = 'POST';
 
   final CacheOptions _options;
   final CacheStore _store;
@@ -28,13 +29,13 @@ class DioCacheInterceptor extends Interceptor {
     RequestOptions request,
     RequestInterceptorHandler handler,
   ) async {
-    if (_shouldSkipRequest(request)) {
+    final options = _getCacheOptions(request);
+
+    if (_shouldSkipRequest(request, options: options)) {
       handler.next(request);
       return;
     }
 
-    final options = _getCacheOptions(request);
-
     if (options.policy != CachePolicy.refresh &&
         options.policy != CachePolicy.refreshForceCache) {
       final cacheResp = await _getCacheResponse(request);
@@ -57,13 +58,14 @@ class DioCacheInterceptor extends Interceptor {
     Response response,
     ResponseInterceptorHandler handler,
   ) async {
-    if (_shouldSkipRequest(response.requestOptions) ||
+    final options = _getCacheOptions(response.requestOptions);
+
+    if (_shouldSkipRequest(response.requestOptions, options: options) ||
         response.statusCode != 200) {
       handler.next(response);
       return;
     }
 
-    final options = _getCacheOptions(response.requestOptions);
     final policy = options.policy;
 
     if (policy == CachePolicy.noCache) {
@@ -93,7 +95,9 @@ class DioCacheInterceptor extends Interceptor {
     DioError err,
     ErrorInterceptorHandler handler,
   ) async {
-    if (_shouldSkipRequest(err.requestOptions, error: err)) {
+    final options = _getCacheOptions(err.requestOptions);
+
+    if (_shouldSkipRequest(err.requestOptions, options: options, error: err)) {
       handler.next(err);
       return;
     }
@@ -105,7 +109,6 @@ class DioCacheInterceptor extends Interceptor {
       returnResponse = true;
     } else {
       // Check if we can return cache
-      final options = _getCacheOptions(err.requestOptions);
       final hcoeExcept = options.hitCacheOnErrorExcept;
 
       if (hcoeExcept != null) {
@@ -184,9 +187,19 @@ class DioCacheInterceptor extends Interceptor {
     return options.store ?? _store;
   }
 
-  bool _shouldSkipRequest(RequestOptions? request, {DioError? error}) {
-    var result = error?.type == DioErrorType.cancel;
-    result |= (request?.method.toUpperCase() != _getMethodName);
+  bool _shouldSkipRequest(
+    RequestOptions? request, {
+    required CacheOptions options,
+    DioError? error,
+  }) {
+    if (error?.type == DioErrorType.cancel) {
+      return true;
+    }
+
+    final rqMethod = request?.method.toUpperCase();
+    var result = (rqMethod != _getMethodName);
+    result &= (!options.allowPostMethod || rqMethod != _postMethodName);
+
     return result;
   }
 

lib/src/model/cache_options.dart

@@ -71,6 +71,9 @@ class CacheOptions {
   /// Optional method to decrypt/encrypt cache content
   final CacheCipher? cipher;
 
+  /// allow POST method request to be cached.
+  final bool allowPostMethod;
+
   // Key to retrieve options from request
   static const _extraKey = '@cache_options@';
 
@@ -84,6 +87,7 @@ class CacheOptions {
     this.maxStale,
     this.priority = CachePriority.normal,
     this.cipher,
+    this.allowPostMethod = false,
     required this.store,
   });
 
@@ -111,6 +115,7 @@ class CacheOptions {
     CachePriority? priority,
     CacheStore? store,
     CacheCipher? cipher,
+    bool? allowPostMethod,
   }) {
     return CacheOptions(
       policy: policy ?? this.policy,
@@ -121,6 +126,7 @@ class CacheOptions {
       priority: priority ?? this.priority,
       store: store ?? this.store,
       cipher: cipher ?? this.cipher,
+      allowPostMethod: allowPostMethod ?? this.allowPostMethod,
     );
   }
 }

pubspec.yaml

@@ -3,7 +3,7 @@ description: Dio HTTP cache interceptor with multiple stores respecting HTTP dir
 repository: https://github.com/llfbandit/dio_cache_interceptor
 issue_tracker: https://github.com/llfbandit/dio_cache_interceptor/issues
 
-version: 2.2.0
+version: 2.3.0
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
@@ -24,7 +24,7 @@ dev_dependencies:
   # https://pub.dev/packages/moor_generator
   moor_generator: ^4.2.1
   # https://pub.dev/packages/build_runner
-  build_runner: ^1.12.2
+  build_runner: ^2.0.1
   # https://pub.dev/packages/pedantic
   pedantic: ^1.11.0
   # https://pub.dev/packages/sqlite3

test/cache_interceptor_test.dart

@@ -157,6 +157,19 @@ void main() {
     expect(resp.extra[CacheResponse.cacheKey], isNull);
   });
 
+  test('Fetch post doesn\'t skip request', () async {
+    final resp = await _dio.post(
+      '${MockHttpClientAdapter.mockBase}/post',
+      options: Options(
+        extra: options.copyWith(allowPostMethod: true).toExtra(),
+      ),
+    );
+
+    expect(resp.statusCode, equals(200));
+    expect(resp.data['path'], equals('/post'));
+    expect(resp.extra[CacheResponse.cacheKey], isNotNull);
+  });
+
   test('Fetch hitCacheOnErrorExcept 500', () async {
     final resp = await _dio.get('${MockHttpClientAdapter.mockBase}/ok');
     final cacheKey = resp.extra[CacheResponse.cacheKey];

test/mock_httpclient_adapter.dart

@@ -62,7 +62,8 @@ class MockHttpClientAdapter extends HttpClientAdapter {
           jsonEncode({'path': uri.path}),
           200,
           headers: {
-            Headers.contentTypeHeader: [Headers.jsonContentType]
+            Headers.contentTypeHeader: [Headers.jsonContentType],
+            'etag': ['1234'],
           },
         );
       case '/exception':