GrpcOrGrpcWeb: provide more flexible constructors (#484) (#485)

lib/grpc_or_grpcweb.dart

@@ -13,17 +13,71 @@
 // 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].
+import 'src/client/grpc_or_grpcweb_channel_grpc.dart'
+    if (dart.library.html) 'src/client/grpc_or_grpcweb_channel_web.dart';
+import 'src/client/http2_channel.dart';
+import 'src/client/options.dart';
+
+/// A client channel that underneath uses gRPC [ClientChannel] on all platforms
+/// 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 for this to work.
-/// As several existing implementations (such as in-process gRPC-web to gRPC
-/// proxies or Envoy gRPC-web to gRPC proxy) expose gRPC and gRPC-web on
-/// separate ports, the constructor requires 2 ports to be provided and
-/// the channel will use the one for the actual protocol being used.
-/// If the server supports both protocols on the same port (such as AspNetCore
-/// implementation), then the same port value should be provided on both params.
+/// Depending on its exact setup, the server may expose gRPC and gRPC-web on the
+/// same port (this is the standard setup of AspNetCore implementation for
+/// example), on separate ports of the same host (common setup of in-process
+/// gRPC-web to gRPC proxies or colocated Envoy gRPC-web to gRPC proxy), or as
+/// a completely separate endpoints (for example if Envoy and gRPC server are
+/// exposed as different kubernetes services). A corresponding constructor is
+/// provided for each case.
+class GrpcOrGrpcWebClientChannel extends GrpcOrGrpcWebClientChannelInternal {
+  GrpcOrGrpcWebClientChannel.toSeparateEndpoints({
+    required String grpcHost,
+    required int grpcPort,
+    required bool grpcTransportSecure,
+    required String grpcWebHost,
+    required int grpcWebPort,
+    required bool grpcWebTransportSecure,
+  }) : super(
+          grpcHost: grpcHost,
+          grpcPort: grpcPort,
+          grpcTransportSecure: grpcTransportSecure,
+          grpcWebHost: grpcWebHost,
+          grpcWebPort: grpcWebPort,
+          grpcWebTransportSecure: grpcWebTransportSecure,
+        );
 
-export 'src/client/grpc_or_grpcweb_channel_grpc.dart'
-    if (dart.library.html) 'src/client/grpc_or_grpcweb_channel_web.dart';
+  GrpcOrGrpcWebClientChannel.toSeparatePorts({
+    required String host,
+    required int grpcPort,
+    required bool grpcTransportSecure,
+    required int grpcWebPort,
+    required bool grpcWebTransportSecure,
+  }) : super(
+          grpcHost: host,
+          grpcPort: grpcPort,
+          grpcTransportSecure: grpcTransportSecure,
+          grpcWebHost: host,
+          grpcWebPort: grpcWebPort,
+          grpcWebTransportSecure: grpcWebTransportSecure,
+        );
+
+  GrpcOrGrpcWebClientChannel.toSingleEndpoint({
+    required String host,
+    required int port,
+    required bool transportSecure,
+  }) : super(
+          grpcHost: host,
+          grpcPort: port,
+          grpcTransportSecure: transportSecure,
+          grpcWebHost: host,
+          grpcWebPort: port,
+          grpcWebTransportSecure: transportSecure,
+        );
+
+  GrpcOrGrpcWebClientChannel.grpc(
+    Object host, {
+    int port = 443,
+    ChannelOptions options = const ChannelOptions(),
+  }) : super.grpc(host, port: port, options: options);
+}

lib/src/client/grpc_or_grpcweb_channel_grpc.dart

@@ -17,25 +17,27 @@ import 'http2_channel.dart';
 import 'options.dart';
 import 'transport/http2_credentials.dart';
 
-class GrpcOrGrpcWebClientChannel extends ClientChannel {
-  GrpcOrGrpcWebClientChannel({
-    required String host,
+class GrpcOrGrpcWebClientChannelInternal extends ClientChannel {
+  GrpcOrGrpcWebClientChannelInternal({
+    required String grpcHost,
     required int grpcPort,
+    required bool grpcTransportSecure,
+    required String grpcWebHost,
     required int grpcWebPort,
-    required bool secure,
+    required bool grpcWebTransportSecure,
   }) : super(
-          host,
+          grpcHost,
           port: grpcPort,
           options: ChannelOptions(
-            credentials: secure
+            credentials: grpcTransportSecure
                 ? ChannelCredentials.secure()
                 : ChannelCredentials.insecure(),
           ),
         );
 
-  GrpcOrGrpcWebClientChannel.grpc(
+  GrpcOrGrpcWebClientChannelInternal.grpc(
     Object host, {
-    int port = 443,
-    ChannelOptions options = const ChannelOptions(),
+    required int port,
+    required ChannelOptions options,
   }) : super(host, port: port, options: options);
 }

lib/src/client/grpc_or_grpcweb_channel_web.dart

@@ -16,19 +16,24 @@
 import 'options.dart';
 import 'web_channel.dart';
 
-class GrpcOrGrpcWebClientChannel extends GrpcWebClientChannel {
-  GrpcOrGrpcWebClientChannel({
-    required String host,
+class GrpcOrGrpcWebClientChannelInternal extends GrpcWebClientChannel {
+  GrpcOrGrpcWebClientChannelInternal({
+    required String grpcHost,
     required int grpcPort,
+    required bool grpcTransportSecure,
+    required String grpcWebHost,
     required int grpcWebPort,
-    required bool secure,
+    required bool grpcWebTransportSecure,
   }) : super.xhr(Uri(
-            host: host, port: grpcWebPort, scheme: secure ? 'https' : 'http'));
+          host: grpcWebHost,
+          port: grpcWebPort,
+          scheme: grpcWebTransportSecure ? 'https' : 'http',
+        ));
 
-  GrpcOrGrpcWebClientChannel.grpc(
+  GrpcOrGrpcWebClientChannelInternal.grpc(
     Object host, {
-    int port = 443,
-    ChannelOptions options = const ChannelOptions(),
+    required int port,
+    required ChannelOptions options,
   }) : super.xhr(
           Uri(
               host: host.toString(),

test/client_tests/grpc_or_grpcweb_channel_grpc_test.dart

@@ -19,32 +19,30 @@ import 'package:grpc/grpc_or_grpcweb.dart';
 import 'package:test/test.dart';
 
 const host = 'example.com';
-const grpcPort = 9090;
-const grpcWebPort = 8080;
+const port = 8080;
 
 void main() {
   test('Channel on non-web uses gRPC ClientChannel with correct params', () {
-    final channel = GrpcOrGrpcWebClientChannel(
+    final channel = GrpcOrGrpcWebClientChannel.toSingleEndpoint(
       host: host,
-      grpcPort: grpcPort,
-      grpcWebPort: grpcWebPort,
-      secure: false,
+      port: port,
+      transportSecure: false,
     );
     expect(channel is ClientChannel, isTrue);
     expect(channel.host, equals(host));
-    expect(channel.port, equals(grpcPort));
+    expect(channel.port, equals(port));
     expect(channel.options.credentials.isSecure, isFalse);
   });
 
   test('Constructor grpc on non-web passes params correctly', () {
     final options = ChannelOptions(credentials: ChannelCredentials.insecure());
     final channel = GrpcOrGrpcWebClientChannel.grpc(
       host,
-      port: grpcPort,
+      port: port,
       options: options,
     );
     expect(channel.host, equals(host));
-    expect(channel.port, equals(grpcPort));
+    expect(channel.port, equals(port));
     expect(channel.options, same(options));
   });
 }

test/client_tests/grpc_or_grpcweb_channel_web_test.dart

@@ -19,25 +19,23 @@ import 'package:grpc/grpc_web.dart';
 import 'package:test/test.dart';
 
 const host = 'example.com';
-const grpcPort = 9090;
-const grpcWebPort = 8080;
+const port = 8080;
 
 void main() {
   test('Channel on web uses GrpcWebClientChannel with correct URI', () {
-    final channel = GrpcOrGrpcWebClientChannel(
+    final channel = GrpcOrGrpcWebClientChannel.toSingleEndpoint(
       host: host,
-      grpcPort: grpcPort,
-      grpcWebPort: grpcWebPort,
-      secure: true,
+      port: port,
+      transportSecure: true,
     );
     expect(channel is GrpcWebClientChannel, isTrue);
     final webChannel = channel as GrpcWebClientChannel;
-    expect(webChannel.uri,
-        equals(Uri(host: host, port: grpcWebPort, scheme: 'https')));
+    expect(
+        webChannel.uri, equals(Uri(host: host, port: port, scheme: 'https')));
   });
 
   test('Constructor grpc on web throws UnsupportedError', () {
-    expect(() => GrpcOrGrpcWebClientChannel.grpc(host, port: grpcPort),
+    expect(() => GrpcOrGrpcWebClientChannel.grpc(host, port: port),
         throwsUnsupportedError);
   });
 }