remoting/webapp/background/it2me_helper_channel.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview
   7  *
   8  * It2MeHelperChannel relays messages between Hangouts and Chrome Remote Desktop
   9  * (webapp) for the helper (the Hangouts participant who is giving remote
  10  * assistance).
  11  *
  12  * It runs in the background page and contains two chrome.runtime.Port objects,
  13  * representing connections to the webapp and hangout, respectively.
  14  *
  15  * Connection is always initiated from Hangouts by calling
  16  *   var port = chrome.runtime.connect({name:'it2me.helper.hangout'}, extId).
  17  *   port.postMessage('hello')
  18  * If the webapp is not installed, |port.onDisconnect| will fire.
  19  * If the webapp is installed, Hangouts will receive a hello response with the
  20  * list of supported features.
  21  *
  22  *   Hangout                     It2MeHelperChannel        Chrome Remote Desktop
  23  *      |-----runtime.connect() ------>|                                |
  24  *      |--------hello message-------->|                                |
  25  *      |                              |<-----helloResponse message-----|
  26  *      |-------connect message------->|                                |
  27  *      |                              |-------appLauncher.launch()---->|
  28  *      |                              |<------runtime.connect()------- |
  29  *      |                              |<-----sessionStateChanged------ |
  30  *      |<----sessionStateChanged------|                                |
  31  *
  32  * Disconnection can be initiated from either side:
  33  * 1. In the normal flow initiated from hangout
  34  *    Hangout                    It2MeHelperChannel        Chrome Remote Desktop
  35  *       |-----disconnect message------>|                               |
  36  *       |<-sessionStateChanged(CLOSED)-|                               |
  37  *       |                              |-----appLauncher.close()------>|
  38  *
  39  * 2. In the normal flow initiated from webapp
  40  *    Hangout                    It2MeHelperChannel        Chrome Remote Desktop
  41  *       |                              |<-sessionStateChanged(CLOSED)--|
  42  *       |                              |<--------port.disconnect()-----|
  43  *       |<--------port.disconnect()----|                               |
  44  *
  45  * 2. If hangout crashes
  46  *    Hangout                    It2MeHelperChannel        Chrome Remote Desktop
  47  *       |---------port.disconnect()--->|                               |
  48  *       |                              |--------port.disconnect()----->|
  49  *       |                              |------appLauncher.close()----->|
  50  *
  51  * 3. If webapp crashes
  52  *    Hangout                    It2MeHelperChannel        Chrome Remote Desktop
  53  *       |                              |<-------port.disconnect()------|
  54  *       |<-sessionStateChanged(FAILED)-|                               |
  55  *       |<--------port.disconnect()----|                               |
  56  */
  57
  58 'use strict';
  59
  60 /** @suppress {duplicate} */
  61 var remoting = remoting || {};
  62
  63 /**
  64  * @param {remoting.AppLauncher} appLauncher
  65  * @param {chrome.runtime.Port} hangoutPort Represents an active connection to
  66  *     Hangouts.
  67  * @param {function(remoting.It2MeHelperChannel)} onDisconnectCallback Callback
  68  *     to notify when the connection is torn down.  IT2MeService uses this
  69  *     callback to dispose of the channel object.
  70  * @constructor
  71  */
  72 remoting.It2MeHelperChannel =
  73     function(appLauncher, hangoutPort, onDisconnectCallback) {
  74
  75   /**
  76    * @type {remoting.AppLauncher}
  77    * @private
  78    */
  79   this.appLauncher_ = appLauncher;
  80
  81   /**
  82    * @type {chrome.runtime.Port}
  83    * @private
  84    */
  85   this.hangoutPort_ = hangoutPort;
  86
  87   /**
  88    * @type {chrome.runtime.Port}
  89    * @private
  90    */
  91   this.webappPort_ = null;
  92
  93   /**
  94    * @type {string}
  95    * @private
  96    */
  97   this.instanceId_ = '';
  98
  99   /**
 100    * @type {remoting.ClientSession.State}
 101    * @private
 102    */
 103   this.sessionState_ = remoting.ClientSession.State.CONNECTING;
 104
 105   /**
 106    * @type {?function(remoting.It2MeHelperChannel)}
 107    * @private
 108    */
 109   this.onDisconnectCallback_ = onDisconnectCallback;
 110
 111   this.onWebappMessageRef_ = this.onWebappMessage_.bind(this);
 112   this.onWebappDisconnectRef_ = this.onWebappDisconnect_.bind(this);
 113   this.onHangoutMessageRef_ = this.onHangoutMessage_.bind(this);
 114   this.onHangoutDisconnectRef_ = this.onHangoutDisconnect_.bind(this);
 115 };
 116
 117 /** @enum {string} */
 118 remoting.It2MeHelperChannel.HangoutMessageTypes = {
 119   HELLO: 'hello',
 120   HELLO_RESPONSE: 'helloResponse',
 121   CONNECT: 'connect',
 122   DISCONNECT: 'disconnect',
 123   ERROR: 'error'
 124 };
 125
 126 /** @enum {string} */
 127 remoting.It2MeHelperChannel.Features = {
 128   REMOTE_ASSISTANCE: 'remoteAssistance'
 129 };
 130
 131 /** @enum {string} */
 132 remoting.It2MeHelperChannel.WebappMessageTypes = {
 133   SESSION_STATE_CHANGED: 'sessionStateChanged'
 134 };
 135
 136 remoting.It2MeHelperChannel.prototype.init = function() {
 137   this.hangoutPort_.onMessage.addListener(this.onHangoutMessageRef_);
 138   this.hangoutPort_.onDisconnect.addListener(this.onHangoutDisconnectRef_);
 139 };
 140
 141 /** @return {string} */
 142 remoting.It2MeHelperChannel.prototype.instanceId = function() {
 143   return this.instanceId_;
 144 };
 145
 146 /**
 147  * @param {{method:string, data:Object.<string,*>}} message
 148  * @return {boolean} whether the message is handled or not.
 149  * @private
 150  */
 151 remoting.It2MeHelperChannel.prototype.onHangoutMessage_ = function(message) {
 152   try {
 153     var MessageTypes = remoting.It2MeHelperChannel.HangoutMessageTypes;
 154     switch (message.method) {
 155       case MessageTypes.CONNECT:
 156         this.launchWebapp_(message);
 157         return true;
 158       case MessageTypes.DISCONNECT:
 159         this.closeWebapp_(message);
 160         return true;
 161       case MessageTypes.HELLO:
 162         this.hangoutPort_.postMessage({
 163           method: MessageTypes.HELLO_RESPONSE,
 164           supportedFeatures: base.values(remoting.It2MeHelperChannel.Features)
 165         });
 166         return true;
 167     }
 168     throw new Error('Unknown message method=' + message.method);
 169   } catch(e) {
 170     var error = /** @type {Error} */ e;
 171     this.sendErrorResponse_(this.hangoutPort_, error, message);
 172   }
 173   return false;
 174 };
 175
 176 /**
 177  * Disconnect the existing connection to the helpee.
 178  *
 179  * @param {{method:string, data:Object.<string,*>}} message
 180  * @private
 181  */
 182 remoting.It2MeHelperChannel.prototype.closeWebapp_ =
 183     function(message) {
 184   // TODO(kelvinp): Closing the v2 app currently doesn't disconnect the IT2me
 185   // session (crbug.com/402137), so send an explicit notification to Hangouts.
 186   this.sessionState_ = remoting.ClientSession.State.CLOSED;
 187   this.hangoutPort_.postMessage({
 188     method: 'sessionStateChanged',
 189     state: this.sessionState_
 190   });
 191   this.appLauncher_.close(this.instanceId_);
 192 };
 193
 194 /**
 195  * Launches the web app.
 196  *
 197  * @param {{method:string, data:Object.<string,*>}} message
 198  * @private
 199  */
 200 remoting.It2MeHelperChannel.prototype.launchWebapp_ =
 201     function(message) {
 202   var accessCode = getStringAttr(message, 'accessCode');
 203   if (!accessCode) {
 204     throw new Error('Access code is missing');
 205   }
 206
 207   // Launch the webapp.
 208   this.appLauncher_.launch({
 209     mode: 'hangout',
 210     accessCode: accessCode
 211   }).then(
 212     /**
 213      * @this {remoting.It2MeHelperChannel}
 214      * @param {string} instanceId
 215      */
 216     function(instanceId){
 217       this.instanceId_ = instanceId;
 218     }.bind(this));
 219 };
 220
 221 /**
 222  * @private
 223  */
 224 remoting.It2MeHelperChannel.prototype.onHangoutDisconnect_ = function() {
 225   this.appLauncher_.close(this.instanceId_);
 226   this.unhookPorts_();
 227 };
 228
 229 /**
 230  * @param {chrome.runtime.Port} port The port represents a connection to the
 231  *     webapp.
 232  * @param {string} id The id of the tab or window that is hosting the webapp.
 233  */
 234 remoting.It2MeHelperChannel.prototype.onWebappConnect = function(port, id) {
 235   base.debug.assert(id === this.instanceId_);
 236   base.debug.assert(this.hangoutPort_ !== null);
 237
 238   // Hook listeners.
 239   port.onMessage.addListener(this.onWebappMessageRef_);
 240   port.onDisconnect.addListener(this.onWebappDisconnectRef_);
 241   this.webappPort_ = port;
 242 };
 243
 244 /** @param {chrome.runtime.Port} port The webapp port. */
 245 remoting.It2MeHelperChannel.prototype.onWebappDisconnect_ = function(port) {
 246   // If the webapp port got disconnected while the session is still connected,
 247   // treat it as an error.
 248   var States = remoting.ClientSession.State;
 249   if (this.sessionState_ === States.CONNECTING ||
 250       this.sessionState_ === States.CONNECTED) {
 251     this.sessionState_ = States.FAILED;
 252     this.hangoutPort_.postMessage({
 253       method: 'sessionStateChanged',
 254       state: this.sessionState_
 255     });
 256   }
 257   this.unhookPorts_();
 258 };
 259
 260 /**
 261  * @param {{method:string, data:Object.<string,*>}} message
 262  * @private
 263  */
 264 remoting.It2MeHelperChannel.prototype.onWebappMessage_ = function(message) {
 265   try {
 266     console.log('It2MeHelperChannel id=' + this.instanceId_ +
 267                 ' incoming message method=' + message.method);
 268     var MessageTypes = remoting.It2MeHelperChannel.WebappMessageTypes;
 269     switch (message.method) {
 270       case MessageTypes.SESSION_STATE_CHANGED:
 271         var state = getNumberAttr(message, 'state');
 272         this.sessionState_ =
 273             /** @type {remoting.ClientSession.State} */ state;
 274         this.hangoutPort_.postMessage(message);
 275         return true;
 276     }
 277     throw new Error('Unknown message method=' + message.method);
 278   } catch(e) {
 279     var error = /** @type {Error} */ e;
 280     this.sendErrorResponse_(this.webappPort_, error, message);
 281   }
 282   return false;
 283 };
 284
 285 remoting.It2MeHelperChannel.prototype.unhookPorts_ = function() {
 286   if (this.webappPort_) {
 287     this.webappPort_.onMessage.removeListener(this.onWebappMessageRef_);
 288     this.webappPort_.onDisconnect.removeListener(this.onWebappDisconnectRef_);
 289     this.webappPort_.disconnect();
 290     this.webappPort_ = null;
 291   }
 292
 293   if (this.hangoutPort_) {
 294     this.hangoutPort_.onMessage.removeListener(this.onHangoutMessageRef_);
 295     this.hangoutPort_.onDisconnect.removeListener(this.onHangoutDisconnectRef_);
 296     this.hangoutPort_.disconnect();
 297     this.hangoutPort_ = null;
 298   }
 299
 300   if (this.onDisconnectCallback_) {
 301     this.onDisconnectCallback_(this);
 302     this.onDisconnectCallback_  = null;
 303   }
 304 };
 305
 306 /**
 307  * @param {chrome.runtime.Port} port
 308  * @param {string|Error} error
 309  * @param {?{method:string, data:Object.<string,*>}=} opt_incomingMessage
 310  * @private
 311  */
 312 remoting.It2MeHelperChannel.prototype.sendErrorResponse_ =
 313     function(port, error, opt_incomingMessage) {
 314   if (error instanceof Error) {
 315     error = error.message;
 316   }
 317
 318   console.error('Error responding to message method:' +
 319                 (opt_incomingMessage ? opt_incomingMessage.method : 'null') +
 320                 ' error:' + error);
 321   port.postMessage({
 322     method: remoting.It2MeHelperChannel.HangoutMessageTypes.ERROR,
 323     message: error,
 324     request: opt_incomingMessage
 325   });
 326 };