runtime/bin/vmservice/client/lib/service_html.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.

library service_html;

import 'dart:async';
import 'dart:convert';
import 'dart:html';

import 'package:observatory/service_common.dart';

// Export the service library.
export 'package:observatory/service_common.dart';

class _HtmlWebSocket implements CommonWebSocket {
  WebSocket _webSocket;

  void connect(String address,
               void onOpen(),
               void onMessage(dynamic data),
               void onError(),
               void onClose()) {
    _webSocket = new WebSocket(address);
    _webSocket.onClose.listen((CloseEvent) => onClose());
    _webSocket.onError.listen((Event) => onError());
    _webSocket.onOpen.listen((Event) => onOpen());
    _webSocket.onMessage.listen((MessageEvent event) => onMessage(event.data));
  }
  
  bool get isOpen => _webSocket.readyState == WebSocket.OPEN;
  
  void send(dynamic data) {
    _webSocket.send(data);
  }
  
  void close() {
    _webSocket.close();
  }
}

/// The [WebSocketVM] communicates with a Dart VM over WebSocket. The Dart VM
/// can be embedded in Chromium or standalone. In the case of Chromium, we
/// make the service requests via the Chrome Remote Debugging Protocol.
class WebSocketVM extends CommonWebSocketVM {
  WebSocketVM(WebSocketVMTarget target) : super(target, new _HtmlWebSocket());
}

// A VM that communicates with the service via posting messages from DevTools.
class PostMessageVM extends VM {
  final Completer _connected = new Completer();
  final Completer _disconnected = new Completer();
  void disconnect() { /* nope */ }
  Future get onConnect => _connected.future;
  Future get onDisconnect => _disconnected.future;
  final Map<String, Completer> _pendingRequests =
      new Map<String, Completer>();
  int _requestSerial = 0;

  PostMessageVM() : super() {
    window.onMessage.listen(_messageHandler);
    _connected.complete(this);
  }

  void _messageHandler(msg) {
    var id = msg.data['id'];
    var name = msg.data['name'];
    var data = msg.data['data'];
    if (name != 'observatoryData') {
      return;
    }
    var completer = _pendingRequests[id];
    assert(completer != null);
    _pendingRequests.remove(id);
    completer.complete(data);
  }

  Future<String> getString(String path) {
    var idString = '$_requestSerial';
    Map message = {};
    message['id'] = idString;
    message['method'] = 'observatoryQuery';
    message['query'] = '$path';
    _requestSerial++;
    var completer = new Completer();
    _pendingRequests[idString] = completer;
    window.parent.postMessage(JSON.encode(message), '*');
    return completer.future;
  }
}