Add GrpcOrGrpcWebClientChannel (#457) (#479)

CHANGELOG.md

@@ -7,6 +7,8 @@
   200 HTTP status and a supported `Content-Type` header to be present, as well
   as `grpc-status: 0` header. When handling malformed responses make effort
   to translate HTTP statuses into gRPC statuses.
+* Add GrpcOrGrpcWebClientChannel which uses gRPC on all platforms except web,
+  on which it uses gRPC-web.
 
 ## 3.0.0
 

lib/grpc_or_grpcweb.dart

@@ -0,0 +1,25 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/// Exports [GrpcOrWebClientChannel] that underneath uses gRPC [ClientChannel]
+/// on all platfroms except web, on which it uses [GrpcWebClientChannel].
+///
+/// Note that gRPC and gRPC-web are 2 different protocols and server must be
+/// able to speak both of them (on separate ports) for this to work. Therefore
+/// applications using this class must provide both ports and the channel will
+/// use the one for the actual protocol being used.
+
+export 'src/client/grpc_or_grpcweb_channel_grpc.dart'
+    if (dart.library.html) 'src/client/grpc_or_grpcweb_channel_web.dart';

lib/src/client/grpc_or_grpcweb_channel_grpc.dart

@@ -0,0 +1,45 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'http2_channel.dart';
+import 'options.dart';
+import 'transport/http2_credentials.dart';
+
+class GrpcOrGrpcWebClientChannel extends ClientChannel {
+  GrpcOrGrpcWebClientChannel({
+    required String host,
+    required int grpcPort,
+    required int grpcWebPort,
+    required bool secure,
+  }) : super(
+          host,
+          port: grpcPort,
+          options: ChannelOptions(
+            credentials: secure
+                ? ChannelCredentials.secure()
+                : ChannelCredentials.insecure(),
+          ),
+        ) {
+    if (grpcWebPort == grpcPort) {
+      throw ArgumentError('grpcPort and grpcWebPort cannot be the same');
+    }
+  }
+
+  GrpcOrGrpcWebClientChannel.grpc(
+    Object host, {
+    int port = 443,
+    ChannelOptions options = const ChannelOptions(),
+  }) : super(host, port: port, options: options);
+}

lib/src/client/grpc_or_grpcweb_channel_web.dart

@@ -0,0 +1,45 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'options.dart';
+import 'web_channel.dart';
+
+class GrpcOrGrpcWebClientChannel extends GrpcWebClientChannel {
+  GrpcOrGrpcWebClientChannel({
+    required String host,
+    required int grpcPort,
+    required int grpcWebPort,
+    required bool secure,
+  }) : super.xhr(Uri(
+            host: host, port: grpcWebPort, scheme: secure ? 'https' : 'http')) {
+    if (grpcWebPort == grpcPort) {
+      throw ArgumentError('grpcPort and grpcWebPort cannot be the same');
+    }
+  }
+
+  GrpcOrGrpcWebClientChannel.grpc(
+    Object host, {
+    int port = 443,
+    ChannelOptions options = const ChannelOptions(),
+  }) : super.xhr(
+          Uri(
+              host: host.toString(),
+              port: port,
+              scheme: options.credentials.isSecure ? 'https' : 'http'),
+        ) {
+    // Do not silently ignore options as caller may expect them to have effects.
+    throw UnsupportedError('not supported by gRPC-web');
+  }
+}

test/client_tests/grpc_or_grpcweb_channel_grpc_test.dart

@@ -0,0 +1,61 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+@TestOn('!browser')
+
+import 'package:grpc/grpc.dart';
+import 'package:grpc/grpc_or_grpcweb.dart';
+import 'package:test/test.dart';
+
+const host = 'example.com';
+const grpcPort = 9090;
+const grpcWebPort = 8080;
+
+void main() {
+  test('Channel on non-web uses gRPC ClientChannel with correct params', () {
+    final channel = GrpcOrGrpcWebClientChannel(
+      host: host,
+      grpcPort: grpcPort,
+      grpcWebPort: grpcWebPort,
+      secure: false,
+    );
+    expect(channel is ClientChannel, isTrue);
+    expect(channel.host, equals(host));
+    expect(channel.port, equals(grpcPort));
+    expect(channel.options.credentials.isSecure, isFalse);
+  });
+
+  test('Constructor throws throwsArgumentError if ports are the same', () {
+    expect(
+        () => GrpcOrGrpcWebClientChannel(
+              host: host,
+              grpcPort: grpcPort,
+              grpcWebPort: grpcPort,
+              secure: false,
+            ),
+        throwsArgumentError);
+  });
+
+  test('Constructor grpc on non-web passes params correctly', () {
+    final options = ChannelOptions(credentials: ChannelCredentials.insecure());
+    final channel = GrpcOrGrpcWebClientChannel.grpc(
+      host,
+      port: grpcPort,
+      options: options,
+    );
+    expect(channel.host, equals(host));
+    expect(channel.port, equals(grpcPort));
+    expect(channel.options, same(options));
+  });
+}

test/client_tests/grpc_or_grpcweb_channel_web_test.dart

@@ -0,0 +1,54 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+@TestOn('browser')
+
+import 'package:grpc/grpc_or_grpcweb.dart';
+import 'package:grpc/grpc_web.dart';
+import 'package:test/test.dart';
+
+const host = 'example.com';
+const grpcPort = 9090;
+const grpcWebPort = 8080;
+
+void main() {
+  test('Channel on web uses GrpcWebClientChannel with correct URI', () {
+    final channel = GrpcOrGrpcWebClientChannel(
+      host: host,
+      grpcPort: grpcPort,
+      grpcWebPort: grpcWebPort,
+      secure: true,
+    );
+    expect(channel is GrpcWebClientChannel, isTrue);
+    final webChannel = channel as GrpcWebClientChannel;
+    expect(webChannel.uri,
+        equals(Uri(host: host, port: grpcWebPort, scheme: 'https')));
+  });
+
+  test('Constructor throws throwsArgumentError if ports are the same', () {
+    expect(
+        () => GrpcOrGrpcWebClientChannel(
+              host: host,
+              grpcPort: grpcPort,
+              grpcWebPort: grpcPort,
+              secure: false,
+            ),
+        throwsArgumentError);
+  });
+
+  test('Constructor grpc on web throws UnsupportedError', () {
+    expect(() => GrpcOrGrpcWebClientChannel.grpc(host, port: grpcPort),
+        throwsUnsupportedError);
+  });
+}