Use StreamChannel.

lib/src/peer.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 
-import '../error_code.dart' as error_code;
+import 'package:stream_channel/stream_channel.dart';
+
+import 'channel_manager.dart';
 import 'client.dart';
-import 'exception.dart';
 import 'parameters.dart';
 import 'server.dart';
-import 'two_way_stream.dart';
+import 'utils.dart';
 
 /// A JSON-RPC 2.0 client *and* server.
 ///
 /// This supports bidirectional peer-to-peer communication with another JSON-RPC
 /// 2.0 endpoint. It sends both requests and responses across the same
 /// communication channel and expects to connect to a peer that does the same.
 class Peer implements Client, Server {
-  TwoWayStream _streams;
+  final ChannelManager _manager;
 
   /// The underlying client that handles request-sending and response-receiving
   /// logic.
   Client _client;
 
   /// The underlying server that handles request-receiving and response-sending
   /// logic.
   Server _server;
 
   /// A stream controller that forwards incoming messages to [_server] if
   /// they're requests.
   final _serverIncomingForwarder = new StreamController(sync: true);
 
   /// A stream controller that forwards incoming messages to [_client] if
   /// they're responses.
   final _clientIncomingForwarder = new StreamController(sync: true);
 
-  /// A stream controller that forwards outgoing messages from both [_server]
-  /// and [_client].
-  final _outgoingForwarder = new StreamController(sync: true);
+  Future get done => _manager.done;
+  bool get isClosed => _manager.isClosed;
 
-  Future get done => _streams.done;
-  bool get isClosed => _streams.isClosed;
+  /// Creates a [Peer] that communicates over [channel].
+  ///
+  /// Note that the peer won't begin listening to [channel] until [Peer.listen]
+  /// is called.
+  Peer(StreamChannel<String> channel)
+      : this.withoutJson(channel
+            .transform(jsonDocument)
+            .transform(respondToFormatExceptions));
 
-  /// Creates a [Peer] that reads incoming messages from [incoming] and writes
-  /// outgoing messages to [outgoing].
-  ///
-  /// If [incoming] is a [StreamSink] as well as a [Stream] (for example, a
-  /// `WebSocket`), [outgoing] may be omitted.
-  ///
-  /// Note that the peer won't begin listening to [incoming] until [Peer.listen]
-  /// is called.
-  Peer(Stream<String> incoming, [StreamSink<String> outgoing]) {
-    _streams = new TwoWayStream("Peer", incoming, "incoming",
-        outgoing, "outgoing", onInvalidInput: (message, error) {
-      _streams.add(new RpcException(error_code.PARSE_ERROR,
-          'Invalid JSON: ${error.message}').serialize(message));
-    });
-
-    _outgoingForwarder.stream.listen(_streams.add);
-    _server = new Server.withoutJson(
-        _serverIncomingForwarder.stream, _outgoingForwarder);
-    _client = new Client.withoutJson(
-        _clientIncomingForwarder.stream, _outgoingForwarder);
-  }
-
-  /// Creates a [Peer] that reads incoming decoded messages from [incoming] and
-  /// writes outgoing decoded messages to [outgoing].
+  /// Creates a [Peer] that communicates using decoded messages over [channel].
   ///
   /// Unlike [new Peer], this doesn't read or write JSON strings. Instead, it
   /// reads and writes decoded maps or lists.
   ///
-  /// If [incoming] is a [StreamSink] as well as a [Stream], [outgoing] may be
-  /// omitted.
-  ///
-  /// Note that the peer won't begin listening to [incoming] until
+  /// Note that the peer won't begin listening to [channel] until
   /// [Peer.listen] is called.
-  Peer.withoutJson(Stream incoming, [StreamSink outgoing]) {
-    _streams = new TwoWayStream.withoutJson("Peer", incoming, "incoming",
-        outgoing, "outgoing");
-
-    _outgoingForwarder.stream.listen(_streams.add);
-    _server = new Server.withoutJson(
-        _serverIncomingForwarder.stream, _outgoingForwarder);
-    _client = new Client.withoutJson(
-        _clientIncomingForwarder.stream, _outgoingForwarder);
+  Peer.withoutJson(StreamChannel channel)
+      : _manager = new ChannelManager("Peer", channel) {
+    _server = new Server.withoutJson(new StreamChannel(
+        _serverIncomingForwarder.stream, channel.sink));
+    _client = new Client.withoutJson(new StreamChannel(
+        _clientIncomingForwarder.stream, channel.sink));
   }
 
   // Client methods.
 
   Future sendRequest(String method, [parameters]) =>
       _client.sendRequest(method, parameters);
 
   void sendNotification(String method, [parameters]) =>
       _client.sendNotification(method, parameters);
 
   withBatch(callback()) => _client.withBatch(callback);
 
   // Server methods.
 
   void registerMethod(String name, Function callback) =>
       _server.registerMethod(name, callback);
 
   void registerFallback(callback(Parameters parameters)) =>
       _server.registerFallback(callback);
 
   // Shared methods.
 
   Future listen() {
     _client.listen();
     _server.listen();
-    return _streams.listen((message) {
+    return _manager.listen((message) {
       if (message is Map) {
         if (message.containsKey('result') || message.containsKey('error')) {
           _clientIncomingForwarder.add(message);
         } else {
           _serverIncomingForwarder.add(message);
         }
       } else if (message is List && message.isNotEmpty &&
                  message.first is Map) {
         if (message.first.containsKey('result') ||
             message.first.containsKey('error')) {
           _clientIncomingForwarder.add(message);
         } else {
           _serverIncomingForwarder.add(message);
         }
       } else {
         // Non-Map and -List messages are ill-formed, so we pass them to the
         // server since it knows how to send error responses.
         _serverIncomingForwarder.add(message);
       }
     });
   }
 
   Future close() =>
-      Future.wait([_client.close(), _server.close(), _streams.close()]);
+      Future.wait([_client.close(), _server.close(), _manager.close()]);
 }