Fix for duplicate headers (#397)

.github/workflows/dart.yml

@@ -65,11 +65,16 @@ jobs:
           release-channel: ${{ matrix.sdk }}
       - name: Report version
         run: dart --version
-      - name: Install grpcwebproxy
+      - name: Install envoy
         if: ${{ matrix.platform == 'chrome' }}
         run: |
-          ./tool/install-grpcwebproxy.sh
-          echo "/tmp/grpcwebproxy" >> $GITHUB_PATH
+          sudo apt update
+          sudo apt install apt-transport-https ca-certificates curl gnupg-agent software-properties-common
+          curl -sL 'https://getenvoy.io/gpg' | sudo apt-key add -
+          apt-key fingerprint 6FF974DB | grep "5270 CEAC 57F6 3EBD 9EA9  005D 0253 D0B2 6FF9 74DB"
+          sudo add-apt-repository "deb [arch=amd64] https://dl.bintray.com/tetrate/getenvoy-deb $(lsb_release -cs) stable"
+          sudo apt update
+          sudo apt install -y getenvoy-envoy
         env:
           MATRIX_OS: ${{ matrix.os }}
         shell: bash

CHANGELOG.md

@@ -7,6 +7,8 @@
   newer of protobuf compiler plugin.
 * `Client.$createCall` is deprecated because it does not invoke client
   interceptors.
+* Fix an issue [#380](https://github.com/grpc/grpc-dart/issues/380) causing
+  incorrect duplicated headers in gRPC-Web requests.
 * Change minimum required Dart SDK to 2.8 to enable access to Unix domain sockets.
 * Add support for Unix domain sockets in `Socket.serve` and `ClientChannel`.
 

CONTRIBUTING.md

@@ -37,9 +37,9 @@ pub get
 pub run test
 ```
 
-gRPC-web tests require [`grpcwebproxy`](
-https://github.com/improbable-eng/grpc-web/tree/master/go/grpcwebproxy) by
-Improbable Engineering to be available in the PATH. Pre-built binaries are [available](https://github.com/improbable-eng/grpc-web/releases).
+gRPC-web tests require [`envoy`](
+https://www.envoyproxy.io/docs/envoy/latest/start/start.html) binary to be
+available in the PATH.
 
 ## Guidelines for Pull Requests
 

lib/src/client/transport/xhr_transport.dart

@@ -169,9 +169,6 @@ class XhrClientConnection extends ClientConnection {
     for (final header in metadata.keys) {
       request.setRequestHeader(header, metadata[header]);
     }
-    request.setRequestHeader('Content-Type', 'application/grpc-web+proto');
-    request.setRequestHeader('X-User-Agent', 'grpc-web-dart/0.1');
-    request.setRequestHeader('X-Grpc-Web', '1');
     // Overriding the mimetype allows us to stream and parse the data
     request.overrideMimeType('text/plain; charset=x-user-defined');
     request.responseType = 'text';

test/grpc_web_server.dart

@@ -4,6 +4,7 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:grpc/grpc.dart';
+import 'package:path/path.dart' as p;
 import 'package:stream_channel/stream_channel.dart';
 
 import 'src/generated/echo.pbgrpc.dart';
@@ -30,31 +31,71 @@ class EchoService extends EchoServiceBase {
   }
 }
 
+final envoyPort = 9999;
+
+final envoyConfig = '''
+static_resources:
+  listeners:
+  - name: listener_0
+    address:
+      socket_address: { address: 0.0.0.0, port_value: 0 }
+    filter_chains:
+    - filters:
+      - name: envoy.http_connection_manager
+        config:
+          codec_type: auto
+          stat_prefix: ingress_http
+          route_config:
+            name: local_route
+            virtual_hosts:
+            - name: local_service
+              domains: ["*"]
+              routes:
+              - match: { prefix: "/" }
+                route: { cluster: echo_service }
+              cors:
+                allow_origin_string_match:
+                - prefix: "*"
+                allow_methods: GET, PUT, DELETE, POST, OPTIONS
+                allow_headers: keep-alive,user-agent,cache-control,content-type,content-transfer-encoding,custom-header-1,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout
+                max_age: "1728000"
+                expose_headers: custom-header-1,grpc-status,grpc-message
+          http_filters:
+          - name: envoy.filters.http.grpc_web
+          - name: envoy.filters.http.cors
+          - name: envoy.filters.http.router
+  clusters:
+  - name: echo_service
+    connect_timeout: 0.25s
+    type: static
+    http2_protocol_options: {}
+    lb_policy: round_robin
+    hosts:
+    - socket_address: { address: 127.0.0.1, port_value: %TARGET_PORT% }
+''';
+
 hybridMain(StreamChannel channel) async {
   // Spawn a gRPC server.
   final server = Server([EchoService()]);
   await server.serve(port: 0);
   _info('grpc server listening on ${server.port}');
 
+  // Create Envoy configuration.
+  final tempDir = await Directory.systemTemp.createTemp();
+  final config = p.join(tempDir.path, 'config.yaml');
+  await File(config).writeAsString(
+      envoyConfig.replaceAll('%TARGET_PORT%', server.port.toString()));
+
   // Spawn a proxy that would translate gRPC-web protocol into gRPC protocol
-  // for us. We use grpcwebproxy by Improbable Engineering. See CONTRIBUTING.md
-  // for setup.
+  // for us. We use envoy proxy. See CONTRIBUTING.md for setup.
   Process proxy;
   try {
-    proxy =
-        await Process.start('grpcwebproxy${Platform.isWindows ? '.exe' : ''}', [
-      '--backend_addr',
-      'localhost:${server.port}',
-      '--run_tls_server=false',
-      '--server_http_debug_port',
-      '0',
-      '--allow_all_origins',
-    ]);
+    proxy = await Process.start('envoy', ['-c', config, '-l', 'debug']);
   } catch (e) {
     print('''
-Failed to start grpcwebproxy: $e.
+Failed to start envoy: $e.
 
-Make sure that grpcwebproxy is available in the PATH see CONTRIBUTING.md
+Make sure that envoy is available in the PATH see CONTRIBUTING.md
 if you are running tests locally.
 ''');
     channel.sink.add(0);
@@ -62,28 +103,41 @@ if you are running tests locally.
   }
 
   // Parse output of the proxy process looking for a port it selected.
-  final portRe = RegExp(r'listening for http on: .*:(\d+)');
+  final portRe = RegExp(
+      r'Set listener listener_0 socket factory local address to 0.0.0.0:(\d+)');
 
   proxy.stderr
       .transform(utf8.decoder)
       .transform(const LineSplitter())
       .listen((line) {
-    _info('grpcwebproxy|stderr] $line');
+    _info('envoy|stderr] $line');
+    final m = portRe.firstMatch(line);
+    if (m != null) {
+      channel.sink.add(int.parse(m[1]));
+    }
   });
 
   proxy.stdout
       .transform(utf8.decoder)
       .transform(const LineSplitter())
       .listen((line) {
-    _info('grpcwebproxy|stdout] $line');
-    final m = portRe.firstMatch(line);
-    if (m != null) {
-      final port = int.parse(m[1]);
-      channel.sink.add(port);
+    _info('envoy|stdout] $line');
+  });
+
+  proxy.exitCode.then((value) {
+    _info('proxy quit with ${value}');
+    if (value != 0) {
+      channel.sink.addError('proxy exited with ${value}');
     }
   });
 
-  proxy.exitCode.then((value) => _info('proxy quit with ${value}'));
+  // Wait for the harness to tell us to shutdown.
+  await channel.stream.first;
+  proxy.kill();
+  if (tempDir.existsSync()) {
+    tempDir.deleteSync(recursive: true);
+  }
+  channel.sink.add('EXITED');
 }
 
 void _info(String line) {

test/grpc_web_test.dart

@@ -1,64 +1,100 @@
 @TestOn('browser')
 
+import 'dart:async';
 import 'dart:math' as math;
 
+import 'package:stream_channel/stream_channel.dart';
 import 'package:test/test.dart';
 
 import 'package:grpc/grpc_web.dart';
 
 import 'src/generated/echo.pbgrpc.dart';
 
-/// Starts gRPC server and a gRPC-web proxy (see grpc_web_server.dart for
-/// implementation.
-///
-/// Returns uri which can be used to talk to using gRPC-web channel.
-///
-/// Note: server will be shut down when the test which spawned it finishes
-/// running.
-Future<Uri> startServer() async {
-  // Spawn the server code on the server side, it will send us back port
-  // number we should be talking to.
-  final serverChannel = spawnHybridUri('grpc_web_server.dart');
-  final port = await serverChannel.stream.first;
-
-  // Note: we would like to test https as well, but we can't easily do it
-  // because browsers like chrome don't trust self-signed certificates by
-  // default.
-  return Uri.parse('http://localhost:$port');
-}
-
 void main() {
   // Test verifies that gRPC-web echo example works by talking to a gRPC
   // server (written in Dart) via gRPC-web protocol through a third party
   // gRPC-web proxy.
   test('gRPC-web echo test', () async {
-    final serverUri = await startServer();
-    final channel = GrpcWebClientChannel.xhr(serverUri);
-    final service = EchoServiceClient(channel);
+    final server = await GrpcWebServer.start();
+    try {
+      final channel = GrpcWebClientChannel.xhr(server.uri);
+      final service = EchoServiceClient(channel);
 
-    const testMessage = 'hello from gRPC-web';
+      const testMessage = 'hello from gRPC-web';
 
-    // First test a simple echo request.
-    final response = await service.echo(EchoRequest()..message = testMessage);
-    expect(response.message, equals(testMessage));
-
-    // Now test that streaming requests also works by asking echo server
-    // to send us a number of messages every 100 ms. Check that we receive
-    // them fast enough (if streaming is broken we will receive all of them
-    // in one go).
-    final sw = Stopwatch()..start();
-    final timings = await service
-        .serverStreamingEcho(ServerStreamingEchoRequest()
-          ..message = testMessage
-          ..messageCount = 20
-          ..messageInterval = 100)
-        .map((response) {
+      // First test a simple echo request.
+      final response = await service.echo(EchoRequest()..message = testMessage);
       expect(response.message, equals(testMessage));
-      final timing = sw.elapsedMilliseconds;
-      sw.reset();
-      return timing;
-    }).toList();
-    final maxDelay = timings.reduce(math.max);
-    expect(maxDelay, lessThan(500));
+
+      // Now test that streaming requests also works by asking echo server
+      // to send us a number of messages every 100 ms. Check that we receive
+      // them fast enough (if streaming is broken we will receive all of them
+      // in one go).
+      final sw = Stopwatch()..start();
+      final timings = await service
+          .serverStreamingEcho(ServerStreamingEchoRequest()
+            ..message = testMessage
+            ..messageCount = 20
+            ..messageInterval = 100)
+          .map((response) {
+        expect(response.message, equals(testMessage));
+        final timing = sw.elapsedMilliseconds;
+        sw.reset();
+        return timing;
+      }).toList();
+      final maxDelay = timings.reduce(math.max);
+      expect(maxDelay, lessThan(500));
+    } finally {
+      await server.shutdown();
+    }
   });
 }
+
+class GrpcWebServer {
+  final StreamChannel channel;
+  final Future<void> whenExited;
+  final Uri uri;
+
+  GrpcWebServer(this.channel, this.whenExited, this.uri);
+
+  Future<void> shutdown() async {
+    channel.sink.add('shutdown');
+    await whenExited;
+  }
+
+  /// Starts gRPC server and a gRPC-web proxy (see grpc_web_server.dart for
+  /// implementation.
+  ///
+  /// Returns uri which can be used to talk to using gRPC-web channel.
+  ///
+  /// Note: you need to explicitly call shutdown on the returned object
+  /// otherwise envoy proxy process leaks.
+  static Future<GrpcWebServer> start() async {
+    // Spawn the server code on the server side, it will send us back port
+    // number we should be talking to.
+    final serverChannel = spawnHybridUri('grpc_web_server.dart');
+    final portCompleter = Completer<int>();
+    final exitCompleter = Completer<void>();
+    serverChannel.stream.listen((event) {
+      if (!portCompleter.isCompleted) {
+        portCompleter.complete(event);
+      } else if (event == 'EXITED') {
+        exitCompleter.complete();
+      }
+    }, onError: (e) {
+      if (!portCompleter.isCompleted) {
+        portCompleter.completeError(e);
+      } else if (!exitCompleter.isCompleted) {
+        exitCompleter.completeError(e);
+      }
+    });
+
+    final port = await portCompleter.future;
+
+    // Note: we would like to test https as well, but we can't easily do it
+    // because browsers like chrome don't trust self-signed certificates by
+    // default.
+    return GrpcWebServer(serverChannel, exitCompleter.future,
+        Uri.parse('http://localhost:$port'));
+  }
+}

tool/install-grpcwebproxy.sh

@@ -1,44 +0,0 @@
-#!/bin/sh
-
-set -ex
-
-VERSION=v0.13.0
-SUFFIX=
-WGET=wget
-
-case $TRAVIS_OS_NAME in
-  linux)
-    VARIANT=linux-x86_64
-    ;;
-  osx)
-    VARIANT=osx-x86_64
-    ;;
-  windows)
-    VARIANT=win64.exe
-    SUFFIX=.exe
-    ;;
-esac
-
-case $MATRIX_OS in
-  ubuntu-latest)
-    VARIANT=linux-x86_64
-    ;;
-  macos-latest)
-    VARIANT=osx-x86_64
-    ;;
-  windows-latest)
-    VARIANT=win64.exe
-    SUFFIX=.exe
-    WGET=C:/msys64/usr/bin/wget.exe
-    ;;
-esac
-
-BINARY=grpcwebproxy-${VERSION}-${VARIANT}
-
-${WGET} https://github.com/improbable-eng/grpc-web/releases/download/${VERSION}/${BINARY}.zip -O /tmp/grpcwebproxy.zip
-rm -rf /tmp/grpcwebproxy
-mkdir /tmp/grpcwebproxy
-cd /tmp/grpcwebproxy
-unzip /tmp/grpcwebproxy.zip
-mv dist/${BINARY} ./grpcwebproxy${SUFFIX}
-