Add an IO implementation of WebSocketChannel.

lib/io.dart

+// Copyright (c) 2016, 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 'dart:io';
+
+import 'package:async/async.dart';
+import 'package:stream_channel/stream_channel.dart';
+
+import 'src/channel.dart';
+import 'src/exception.dart';
+import 'src/sink_completer.dart';
+
+/// A [WebSocketChannel] that communicates using a `dart:io` [WebSocket].
+class IOWebSocketChannel extends StreamChannelMixin
+    implements WebSocketChannel {
+  /// The underlying `dart:io` [WebSocket].
+  ///
+  /// If the channel was constructed with [IOWebSocketChannel.connect], this is
+  /// `null` until the [WebSocket.connect] future completes.
+  WebSocket _webSocket;
+
+  Duration get pingInterval =>
+      _webSocket == null ? _pingInterval : _webSocket.pingInterval;
+
+  set pingInterval(Duration value) {
+    if (_webSocket == null) {
+      _pingInterval = value;
+    } else {
+      _webSocket.pingInterval = value;
+    }
+  }
+
+  /// The ping interval set by the user.
+  ///
+  /// This is stored independently of [_webSocket] so that the user can set it
+  /// prior to [_webSocket] getting a value.
+  Duration _pingInterval;
+
+  String get protocol => _webSocket?.protocol;

[kevmoo, 2016/03/01 23:24:46]

document that these can be null if not connected?

[nweiz, 2016/03/02 00:10:20]

That's documented in the superclass.

+  int get closeCode => _webSocket?.closeCode;
+  String get closeReason => _webSocket?.closeReason;
+
+  final Stream stream;
+  final WebSocketSink sink;
+
+  // TODO(nweiz): Add a compression parameter after the initial release.
+
+  /// Creates a new WebSocket connection.
+  ///
+  /// Connects to [url] using [WebSocket.connect] and returns a channel that can
+  /// be used to communicate over the resulting socket. The [url] may be either
+  /// a [String] or a [Uri]; otherwise, the parameters are the same as
+  /// [WebSocket.connect].
+  ///
+  /// If there's an error connecting, the channel's stream emits a
+  /// [WebSocketChannelException] wrapping that error and then closes.
+  factory IOWebSocketChannel.connect(url, {Iterable<String> protocols,
+      Map<String, dynamic> headers}) {
+    var channel;
+    var sinkCompleter = new WebSocketSinkCompleter();
+    var stream = StreamCompleter.fromFuture(
+        WebSocket.connect(url.toString(), headers: headers).then((webSocket) {
+      channel._setWebSocket(webSocket);
+      sinkCompleter.setDestinationSink(new _IOWebSocketSink(webSocket));
+      return webSocket;
+    }).catchError((error) => throw new WebSocketChannelException.from(error)));
+
+    channel = new IOWebSocketChannel._withoutSocket(stream, sinkCompleter.sink);
+    return channel;
+  }
+
+  /// Creates a channel wrapping [socket].
+  IOWebSocketChannel(WebSocket socket)
+      : _webSocket = socket,
+        stream = socket.handleError((error) =>
+            throw new WebSocketChannelException.from(error)),
+        sink = new _IOWebSocketSink(socket);
+
+  /// Creates a channel without a socket.
+  ///
+  /// This is used with [connect] to synchronously provide a channel that later
+  /// has a socket added.
+  IOWebSocketChannel._withoutSocket(Stream stream, this.sink)
+      : _webSocket = null,
+        stream = stream.handleError((error) =>
+            throw new WebSocketChannelException.from(error));
+
+  /// Sets the underlying web socket.
+  ///
+  /// This is called by [connect] once the [WebSocket.connect] future has
+  /// completed.
+  void _setWebSocket(WebSocket webSocket) {
+    assert(_webSocket == null);
+
+    _webSocket = webSocket;
+    if (_pingInterval != null) _webSocket.pingInterval = pingInterval;
+  }
+}
+
+/// A [WebSocketSink] that forwards [close] calls to a `dart:io` [WebSocket].
+class _IOWebSocketSink extends DelegatingStreamSink implements WebSocketSink {
+  /// The underlying socket.
+  final WebSocket _webSocket;
+
+  _IOWebSocketSink(WebSocket webSocket)
+      : super(webSocket),
+        _webSocket = webSocket;
+
+  Future close([int closeCode, String closeReason]) =>
+      _webSocket.close(closeCode, closeReason);
+}