remoting/webapp/wcs_loader.js

   1 /* Copyright (c) 2012 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 /**
   7  * @fileoverview
   8  * A class that loads a WCS IQ client and constructs remoting.wcs as a
   9  * wrapper for it.
  10  */
  11
  12 'use strict';
  13
  14 /** @suppress {duplicate} */
  15 var remoting = remoting || {};
  16
  17 /** @type {remoting.WcsLoader} */
  18 remoting.wcsLoader = null;
  19
  20 /**
  21  * @constructor
  22  */
  23 remoting.WcsLoader = function() {
  24   /**
  25    * The WCS client that will be downloaded. This variable is initialized (via
  26    * remoting.wcsLoader) by the downloaded Javascript.
  27    * @type {remoting.WcsIqClient}
  28    */
  29   this.wcsIqClient = null;
  30 };
  31
  32 /**
  33  * The id of the script node.
  34  * @type {string}
  35  * @private
  36  */
  37 remoting.WcsLoader.prototype.SCRIPT_NODE_ID_ = 'wcs-script-node';
  38
  39 /**
  40  * Starts loading the WCS IQ client.
  41  *
  42  * When it's loaded, construct remoting.wcs as a wrapper for it.
  43  * When the WCS connection is ready, or on error, call |onReady| or |onError|,
  44  * respectively.
  45  *
  46  * @param {string} token An OAuth2 access token.
  47  * @param {function(string): void} onReady The callback function, called with
  48  *     a client JID when WCS has been loaded.
  49  * @param {function(remoting.Error):void} onError Function to invoke with an
  50  *     error code on failure.
  51  * @return {void} Nothing.
  52  */
  53 remoting.WcsLoader.prototype.start = function(token, onReady, onError) {
  54   var node = document.getElementById(this.SCRIPT_NODE_ID_);
  55   if (node) {
  56     console.error('Multiple calls to WcsLoader.start are not allowed.');
  57     onError(remoting.Error.UNEXPECTED);
  58     return;
  59   }
  60
  61   // Create a script node to load the WCS driver.
  62   node = document.createElement('script');
  63   node.id = this.SCRIPT_NODE_ID_;
  64   node.src = remoting.settings.TALK_GADGET_URL + 'iq?access_token=' + token;
  65   node.type = 'text/javascript';
  66   document.body.insertBefore(node, document.body.firstChild);
  67
  68   /** @type {remoting.WcsLoader} */
  69   var that = this;
  70   var onLoad = function() {
  71     that.constructWcs_(token, onReady);
  72   };
  73   var onLoadError = function(event) {
  74     // The DOM Event object has no detail on the nature of the error, so try to
  75     // validate the token to get a better idea.
  76     /** @param {remoting.Error} error Error code. */
  77     var onValidateError = function(error) {
  78       var typedNode = /** @type {Element} */ (node);
  79       typedNode.parentNode.removeChild(node);
  80       onError(error);
  81     };
  82     var onValidateOk = function() {
  83       // We can reach the authentication server and validate the token. Either
  84       // there's something wrong with the talkgadget service, or there is a
  85       // cookie problem. Only the cookie problem can be fixed by the user, so
  86       // suggest that fix.
  87       onValidateError(remoting.Error.AUTHENTICATION_FAILED);
  88     }
  89     that.validateToken(token, onValidateOk, onValidateError);
  90   }
  91   node.addEventListener('load', onLoad, false);
  92   node.addEventListener('error', onLoadError, false);
  93 };
  94
  95 /**
  96  * Constructs the remoting.wcs object.
  97  *
  98  * @param {string} token An OAuth2 access token.
  99  * @param {function(string): void} onReady The callback function, called with
 100  *     an OAuth2 access token when WCS has been loaded.
 101  * @return {void} Nothing.
 102  * @private
 103  */
 104 remoting.WcsLoader.prototype.constructWcs_ = function(token, onReady) {
 105   remoting.wcs = new remoting.Wcs(
 106       remoting.wcsLoader.wcsIqClient, token, onReady);
 107 };
 108
 109 /**
 110  * Validates an OAuth2 access token.
 111  *
 112  * @param {string} token The access token.
 113  * @param {function():void} onOk Callback to invoke if the token is valid.
 114  * @param {function(remoting.Error):void} onError Function to invoke with an
 115  *     error code on failure.
 116  * @return {void} Nothing.
 117  */
 118 remoting.WcsLoader.prototype.validateToken = function(token, onOk, onError) {
 119   /** @type {XMLHttpRequest} */
 120   var xhr = new XMLHttpRequest();
 121   xhr.onreadystatechange = function() {
 122     if (xhr.readyState != 4) {
 123       return;
 124     }
 125     if (xhr.status == 200) {
 126       onOk();
 127     } else {
 128       var error = remoting.Error.AUTHENTICATION_FAILED;
 129       switch (xhr.status) {
 130         case 0:
 131           error = remoting.Error.NETWORK_FAILURE;
 132           break;
 133         case 502: // No break
 134         case 503:
 135           error = remoting.Error.SERVICE_UNAVAILABLE;
 136           break;
 137       }
 138       onError(error);
 139     }
 140   };
 141   var parameters = '?access_token=' + encodeURIComponent(token);
 142   xhr.open('GET',
 143            remoting.settings.OAUTH2_API_BASE_URL + '/v1/tokeninfo' + parameters,
 144            true);
 145   xhr.send(null);
 146 };