fix(dart_frog): Pipeline does not maintain RequestContext (#605)

Author: felangel

examples/counter/test/routes/_middleware_test.dart

@@ -9,25 +9,22 @@ class _MockRequestContext extends Mock implements RequestContext {}
 void main() {
   group('middleware', () {
     test('provides incremented count', () async {
-      int? count;
-      final handler = middleware(
-        (context) {
-          count = context.read<int>();
-          return Response(body: '');
-        },
-      );
+      final handler = middleware((context) => Response());
       final request = Request.get(Uri.parse('http://localhost/'));
       final context = _MockRequestContext();
+
       when(() => context.request).thenReturn(request);
+      when(() => context.provide<int>(any())).thenReturn(context);
 
       await handler(context);
-      expect(count, equals(1));
 
-      await handler(context);
-      expect(count, equals(2));
+      final create = verify(() => context.provide<int>(captureAny()))
+          .captured
+          .single as int Function();
 
-      await handler(context);
-      expect(count, equals(3));
+      expect(create(), equals(1));
+      expect(create(), equals(2));
+      expect(create(), equals(3));
     });
   });
 }

examples/kitchen_sink/test/routes/_middleware_test.dart

@@ -9,19 +9,20 @@ class _MockRequestContext extends Mock implements RequestContext {}
 void main() {
   group('middleware', () {
     test('provides greeting', () async {
-      String? greeting;
-      final handler = middleware(
-        (context) {
-          greeting = context.read<String>();
-          return Response(body: '');
-        },
-      );
+      final handler = middleware((_) => Response());
       final request = Request.get(Uri.parse('http://localhost/'));
       final context = _MockRequestContext();
+
       when(() => context.request).thenReturn(request);
+      when(() => context.provide<String>(any())).thenReturn(context);
 
       await handler(context);
-      expect(greeting, equals('Hello'));
+
+      final create = verify(() => context.provide<String>(captureAny()))
+          .captured
+          .single as String Function();
+
+      expect(create(), equals('Hello'));
     });
   });
 }

examples/web_socket_counter/test/routes/_middleware_test.dart

@@ -10,19 +10,19 @@ class _MockRequestContext extends Mock implements RequestContext {}
 void main() {
   group('middleware', () {
     test('provides a CounterCubit instance.', () async {
-      CounterCubit? cubit;
-      final handler = middleware(
-        (context) {
-          cubit = context.read<CounterCubit>();
-          return Response();
-        },
-      );
+      final handler = middleware((_) => Response());
       final request = Request.get(Uri.parse('http://localhost/'));
       final context = _MockRequestContext();
+
       when(() => context.request).thenReturn(request);
+      when(() => context.provide<CounterCubit>(any())).thenReturn(context);
 
       await handler(context);
-      expect(cubit, isNotNull);
+
+      final create = verify(() => context.provide<CounterCubit>(captureAny()))
+          .captured
+          .single as CounterCubit Function();
+      expect(create(), isA<CounterCubit>());
     });
   });
 }

packages/dart_frog/lib/src/pipeline.dart

@@ -6,44 +6,28 @@ part of '_internal.dart';
 /// {@endtemplate}
 class Pipeline {
   /// {@macro pipeline}
-  const Pipeline() : this._(const shelf.Pipeline());
-
-  const Pipeline._(this._pipeline);
-
-  final shelf.Pipeline _pipeline;
+  const Pipeline();
 
   /// Returns a new [Pipeline] with [middleware] added to the existing set of
   /// [Middleware].
   ///
   /// [middleware] will be the last [Middleware] to process a request and
   /// the first to process a response.
-  Pipeline addMiddleware(Middleware middleware) {
-    return Pipeline._(
-      _pipeline.addMiddleware((innerHandler) {
-        return (request) async {
-          final response = await middleware(
-            (context) async {
-              final response = await innerHandler(context.request._request);
-              return Response._(response);
-            },
-          )(RequestContext._(request));
-          return response._response;
-        };
-      }),
-    );
-  }
+  Pipeline addMiddleware(Middleware middleware) =>
+      _Pipeline(middleware, addHandler);
 
   /// Returns a new [Handler] with [handler] as the final processor of a
   /// [Request] if all of the middleware in the pipeline have passed the request
   /// through.
-  Handler addHandler(Handler handler) {
-    return (context) async {
-      final response = await _pipeline.addHandler((request) async {
-        final context = RequestContext._(request);
-        final response = await handler(context);
-        return response._response;
-      })(context.request._request);
-      return Response._(response);
-    };
-  }
+  Handler addHandler(Handler handler) => handler;
+}
+
+class _Pipeline extends Pipeline {
+  _Pipeline(this._middleware, this._parent);
+
+  final Middleware _middleware;
+  final Middleware _parent;
+
+  @override
+  Handler addHandler(Handler handler) => _parent(_middleware(handler));
 }

packages/dart_frog/test/src/middleware_test.dart

@@ -1,6 +1,7 @@
 import 'dart:io';
 
 import 'package:dart_frog/dart_frog.dart';
+import 'package:http/http.dart' as http;
 import 'package:mocktail/mocktail.dart';
 import 'package:test/test.dart';
 
@@ -31,16 +32,14 @@ void main() {
     final handler =
         const Pipeline().addMiddleware(middleware).addHandler(onRequest);
 
-    final request = Request.get(Uri.parse('http://localhost/'));
-    final context = _MockRequestContext();
-    when(() => context.request).thenReturn(request);
-    final response = await handler(context);
+    final server = await serve(handler, 'localhost', 3020);
+    final client = http.Client();
+    final response = await client.get(Uri.parse('http://localhost:3020/'));
 
     await expectLater(response.statusCode, equals(HttpStatus.ok));
-    await expectLater(
-      await response.body(),
-      equals('$stringValue $intValue'),
-    );
+    await expectLater(response.body, equals('$stringValue $intValue'));
+
+    await server.close();
   });
 
   test('middleware can be used to read the request body', () async {
@@ -119,4 +118,27 @@ void main() {
     expect(response.statusCode, equals(HttpStatus.ok));
     expect(response.body(), completion(equals(body)));
   });
+
+  test('chaining middleware retains request context', () async {
+    const value = 'test-value';
+    Middleware noop() => (handler) => (context) => handler(context);
+
+    Future<Response> onRequest(RequestContext context) async {
+      final value = context.read<String>();
+      return Response(body: value);
+    }
+
+    final handler =
+        const Pipeline().addMiddleware(noop()).addHandler(onRequest);
+    final request = Request.get(Uri.parse('http://localhost/'));
+    final context = _MockRequestContext();
+
+    when(() => context.read<String>()).thenReturn(value);
+    when(() => context.request).thenReturn(request);
+
+    final response = await handler(context);
+
+    expect(response.statusCode, equals(HttpStatus.ok));
+    expect(response.body(), completion(equals(value)));
+  });
 }

packages/dart_frog/test/src/provider_test.dart

@@ -1,11 +1,9 @@
 import 'dart:io';
 
 import 'package:dart_frog/dart_frog.dart';
-import 'package:mocktail/mocktail.dart';
+import 'package:http/http.dart' as http;
 import 'package:test/test.dart';
 
-class _MockRequestContext extends Mock implements RequestContext {}
-
 void main() {
   test('values can be provided and read via middleware', () async {
     const value = '__test_value__';
@@ -21,13 +19,14 @@ void main() {
     final handler =
         const Pipeline().addMiddleware(middleware).addHandler(onRequest);
 
-    final request = Request.get(Uri.parse('http://localhost/'));
-    final context = _MockRequestContext();
-    when(() => context.request).thenReturn(request);
-    final response = await handler(context);
+    final server = await serve(handler, 'localhost', 3010);
+    final client = http.Client();
+    final response = await client.get(Uri.parse('http://localhost:3010/'));
 
     await expectLater(response.statusCode, equals(HttpStatus.ok));
-    await expectLater(await response.body(), equals(value));
+    await expectLater(response.body, equals(value));
+
+    await server.close();
   });
 
   test('descendant providers can access provided values', () async {
@@ -46,29 +45,38 @@ void main() {
     final handler =
         const Pipeline().addMiddleware(middleware).addHandler(onRequest);
 
-    final request = Request.get(Uri.parse('http://localhost/'));
-    final context = _MockRequestContext();
-    when(() => context.request).thenReturn(request);
-    final response = await handler(context);
+    final server = await serve(handler, 'localhost', 3011);
+    final client = http.Client();
+    final response = await client.get(Uri.parse('http://localhost:3011/'));
 
     await expectLater(response.statusCode, equals(HttpStatus.ok));
-    await expectLater(await response.body(), equals(url));
+    await expectLater(response.body, equals(url));
+
+    await server.close();
   });
 
   test('A StateError is thrown when reading an un-provided value', () async {
+    Object? exception;
     Response onRequest(RequestContext context) {
-      context.read<Uri>();
+      try {
+        context.read<Uri>();
+      } catch (e) {
+        exception = e;
+      }
       return Response();
     }
 
     final handler = const Pipeline()
         .addMiddleware((handler) => handler)
         .addHandler(onRequest);
 
-    final request = Request.get(Uri.parse('http://localhost/'));
-    final context = _MockRequestContext();
-    when(() => context.request).thenReturn(request);
+    final server = await serve(handler, 'localhost', 3012);
+    final client = http.Client();
+    final response = await client.get(Uri.parse('http://localhost:3012/'));
+
+    await expectLater(response.statusCode, equals(HttpStatus.ok));
+    expect(exception, isA<StateError>());
 
-    await expectLater(() => handler(context), throwsStateError);
+    await server.close();
   });
 }