openlayers/lib/OpenLayers/Request/XMLHttpRequest.js

   1 // Copyright 2007 Sergey Ilinsky (http://www.ilinsky.com)
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //   http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 /**
  16  * @requires OpenLayers/Request.js
  17  */
  18
  19 (function () {
  20
  21     // Save reference to earlier defined object implementation (if any)
  22     var oXMLHttpRequest    = window.XMLHttpRequest;
  23
  24     // Define on browser type
  25     var bGecko    = !!window.controllers,
  26         bIE        = window.document.all && !window.opera;
  27
  28     // Constructor
  29     function cXMLHttpRequest() {
  30         this._object    = oXMLHttpRequest ? new oXMLHttpRequest : new window.ActiveXObject('Microsoft.XMLHTTP');
  31     };
  32
  33     // BUGFIX: Firefox with Firebug installed would break pages if not executed
  34     if (bGecko && oXMLHttpRequest.wrapped)
  35         cXMLHttpRequest.wrapped    = oXMLHttpRequest.wrapped;
  36
  37     // Constants
  38     cXMLHttpRequest.UNSENT                = 0;
  39     cXMLHttpRequest.OPENED                = 1;
  40     cXMLHttpRequest.HEADERS_RECEIVED    = 2;
  41     cXMLHttpRequest.LOADING                = 3;
  42     cXMLHttpRequest.DONE                = 4;
  43
  44     // Public Properties
  45     cXMLHttpRequest.prototype.readyState    = cXMLHttpRequest.UNSENT;
  46     cXMLHttpRequest.prototype.responseText    = "";
  47     cXMLHttpRequest.prototype.responseXML    = null;
  48     cXMLHttpRequest.prototype.status        = 0;
  49     cXMLHttpRequest.prototype.statusText    = "";
  50
  51     // Instance-level Events Handlers
  52     cXMLHttpRequest.prototype.onreadystatechange    = null;
  53
  54     // Class-level Events Handlers
  55     cXMLHttpRequest.onreadystatechange    = null;
  56     cXMLHttpRequest.onopen                = null;
  57     cXMLHttpRequest.onsend                = null;
  58     cXMLHttpRequest.onabort                = null;
  59
  60     // Public Methods
  61     cXMLHttpRequest.prototype.open    = function(sMethod, sUrl, bAsync, sUser, sPassword) {
  62
  63         // Save async parameter for fixing Gecko bug with missing readystatechange in synchronous requests
  64         this._async        = bAsync;
  65
  66         // Set the onreadystatechange handler
  67         var oRequest    = this,
  68             nState        = this.readyState;
  69
  70         // BUGFIX: IE - memory leak on page unload (inter-page leak)
  71         if (bIE) {
  72             var fOnUnload    = function() {
  73                 if (oRequest._object.readyState != cXMLHttpRequest.DONE)
  74                     fCleanTransport(oRequest);
  75             };
  76             if (bAsync)
  77                 window.attachEvent("onunload", fOnUnload);
  78         }
  79
  80         this._object.onreadystatechange    = function() {
  81             if (bGecko && !bAsync)
  82                 return;
  83
  84             // Synchronize state
  85             oRequest.readyState        = oRequest._object.readyState;
  86
  87             //
  88             fSynchronizeValues(oRequest);
  89
  90             // BUGFIX: Firefox fires unneccesary DONE when aborting
  91             if (oRequest._aborted) {
  92                 // Reset readyState to UNSENT
  93                 oRequest.readyState    = cXMLHttpRequest.UNSENT;
  94
  95                 // Return now
  96                 return;
  97             }
  98
  99             if (oRequest.readyState == cXMLHttpRequest.DONE) {
 100                 //
 101                 fCleanTransport(oRequest);
 102 // Uncomment this block if you need a fix for IE cache
 103 /*
 104                 // BUGFIX: IE - cache issue
 105                 if (!oRequest._object.getResponseHeader("Date")) {
 106                     // Save object to cache
 107                     oRequest._cached    = oRequest._object;
 108
 109                     // Instantiate a new transport object
 110                     cXMLHttpRequest.call(oRequest);
 111
 112                     // Re-send request
 113                     oRequest._object.open(sMethod, sUrl, bAsync, sUser, sPassword);
 114                     oRequest._object.setRequestHeader("If-Modified-Since", oRequest._cached.getResponseHeader("Last-Modified") || new window.Date(0));
 115                     // Copy headers set
 116                     if (oRequest._headers)
 117                         for (var sHeader in oRequest._headers)
 118                             if (typeof oRequest._headers[sHeader] == "string")    // Some frameworks prototype objects with functions
 119                                 oRequest._object.setRequestHeader(sHeader, oRequest._headers[sHeader]);
 120
 121                     oRequest._object.onreadystatechange    = function() {
 122                         // Synchronize state
 123                         oRequest.readyState        = oRequest._object.readyState;
 124
 125                         if (oRequest._aborted) {
 126                             //
 127                             oRequest.readyState    = cXMLHttpRequest.UNSENT;
 128
 129                             // Return
 130                             return;
 131                         }
 132
 133                         if (oRequest.readyState == cXMLHttpRequest.DONE) {
 134                             // Clean Object
 135                             fCleanTransport(oRequest);
 136
 137                             // get cached request
 138                             if (oRequest.status == 304)
 139                                 oRequest._object    = oRequest._cached;
 140
 141                             //
 142                             delete oRequest._cached;
 143
 144                             //
 145                             fSynchronizeValues(oRequest);
 146
 147                             //
 148                             fReadyStateChange(oRequest);
 149
 150                             // BUGFIX: IE - memory leak in interrupted
 151                             if (bIE && bAsync)
 152                                 window.detachEvent("onunload", fOnUnload);
 153                         }
 154                     };
 155                     oRequest._object.send(null);
 156
 157                     // Return now - wait untill re-sent request is finished
 158                     return;
 159                 };
 160 */
 161                 // BUGFIX: IE - memory leak in interrupted
 162                 if (bIE && bAsync)
 163                     window.detachEvent("onunload", fOnUnload);
 164             }
 165
 166             // BUGFIX: Some browsers (Internet Explorer, Gecko) fire OPEN readystate twice
 167             if (nState != oRequest.readyState)
 168                 fReadyStateChange(oRequest);
 169
 170             nState    = oRequest.readyState;
 171         };
 172
 173         // Add method sniffer
 174         if (cXMLHttpRequest.onopen)
 175             cXMLHttpRequest.onopen.apply(this, arguments);
 176
 177         this._object.open(sMethod, sUrl, bAsync, sUser, sPassword);
 178
 179         // BUGFIX: Gecko - missing readystatechange calls in synchronous requests
 180         if (!bAsync && bGecko) {
 181             this.readyState    = cXMLHttpRequest.OPENED;
 182
 183             fReadyStateChange(this);
 184         }
 185     };
 186     cXMLHttpRequest.prototype.send    = function(vData) {
 187         // Add method sniffer
 188         if (cXMLHttpRequest.onsend)
 189             cXMLHttpRequest.onsend.apply(this, arguments);
 190
 191         // BUGFIX: Safari - fails sending documents created/modified dynamically, so an explicit serialization required
 192         // BUGFIX: IE - rewrites any custom mime-type to "text/xml" in case an XMLNode is sent
 193         // BUGFIX: Gecko - fails sending Element (this is up to the implementation either to standard)
 194         if (vData && vData.nodeType) {
 195             vData    = window.XMLSerializer ? new window.XMLSerializer().serializeToString(vData) : vData.xml;
 196             if (!this._headers["Content-Type"])
 197                 this._object.setRequestHeader("Content-Type", "application/xml");
 198         }
 199
 200         this._object.send(vData);
 201
 202         // BUGFIX: Gecko - missing readystatechange calls in synchronous requests
 203         if (bGecko && !this._async) {
 204             this.readyState    = cXMLHttpRequest.OPENED;
 205
 206             // Synchronize state
 207             fSynchronizeValues(this);
 208
 209             // Simulate missing states
 210             while (this.readyState < cXMLHttpRequest.DONE) {
 211                 this.readyState++;
 212                 fReadyStateChange(this);
 213                 // Check if we are aborted
 214                 if (this._aborted)
 215                     return;
 216             }
 217         }
 218     };
 219     cXMLHttpRequest.prototype.abort    = function() {
 220         // Add method sniffer
 221         if (cXMLHttpRequest.onabort)
 222             cXMLHttpRequest.onabort.apply(this, arguments);
 223
 224         // BUGFIX: Gecko - unneccesary DONE when aborting
 225         if (this.readyState > cXMLHttpRequest.UNSENT)
 226             this._aborted    = true;
 227
 228         this._object.abort();
 229
 230         // BUGFIX: IE - memory leak
 231         fCleanTransport(this);
 232     };
 233     cXMLHttpRequest.prototype.getAllResponseHeaders    = function() {
 234         return this._object.getAllResponseHeaders();
 235     };
 236     cXMLHttpRequest.prototype.getResponseHeader    = function(sName) {
 237         return this._object.getResponseHeader(sName);
 238     };
 239     cXMLHttpRequest.prototype.setRequestHeader    = function(sName, sValue) {
 240         // BUGFIX: IE - cache issue
 241         if (!this._headers)
 242             this._headers    = {};
 243         this._headers[sName]    = sValue;
 244
 245         return this._object.setRequestHeader(sName, sValue);
 246     };
 247     cXMLHttpRequest.prototype.toString    = function() {
 248         return '[' + "object" + ' ' + "XMLHttpRequest" + ']';
 249     };
 250     cXMLHttpRequest.toString    = function() {
 251         return '[' + "XMLHttpRequest" + ']';
 252     };
 253
 254     // Helper function
 255     function fReadyStateChange(oRequest) {
 256         // Execute onreadystatechange
 257         if (oRequest.onreadystatechange)
 258             oRequest.onreadystatechange.apply(oRequest);
 259
 260         // Sniffing code
 261         if (cXMLHttpRequest.onreadystatechange)
 262             cXMLHttpRequest.onreadystatechange.apply(oRequest);
 263     };
 264
 265     function fGetDocument(oRequest) {
 266         var oDocument    = oRequest.responseXML;
 267         // Try parsing responseText
 268         if (bIE && oDocument && !oDocument.documentElement && oRequest.getResponseHeader("Content-Type").match(/[^\/]+\/[^\+]+\+xml/)) {
 269             oDocument    = new ActiveXObject('Microsoft.XMLDOM');
 270             oDocument.loadXML(oRequest.responseText);
 271         }
 272         // Check if there is no error in document
 273         if (oDocument)
 274             if ((bIE && oDocument.parseError != 0) || (oDocument.documentElement && oDocument.documentElement.tagName == "parsererror"))
 275                 return null;
 276         return oDocument;
 277     };
 278
 279     function fSynchronizeValues(oRequest) {
 280         try {    oRequest.responseText    = oRequest._object.responseText;    } catch (e) {}
 281         try {    oRequest.responseXML    = fGetDocument(oRequest._object);    } catch (e) {}
 282         try {    oRequest.status            = oRequest._object.status;            } catch (e) {}
 283         try {    oRequest.statusText        = oRequest._object.statusText;        } catch (e) {}
 284     };
 285
 286     function fCleanTransport(oRequest) {
 287         // BUGFIX: IE - memory leak (on-page leak)
 288         oRequest._object.onreadystatechange    = new window.Function;
 289
 290         // Delete private properties
 291         delete oRequest._headers;
 292     };
 293
 294     // Internet Explorer 5.0 (missing apply)
 295     if (!window.Function.prototype.apply) {
 296         window.Function.prototype.apply    = function(oRequest, oArguments) {
 297             if (!oArguments)
 298                 oArguments    = [];
 299             oRequest.__func    = this;
 300             oRequest.__func(oArguments[0], oArguments[1], oArguments[2], oArguments[3], oArguments[4]);
 301             delete oRequest.__func;
 302         };
 303     };
 304
 305     // Register new object with window
 306     /**
 307      * Class: OpenLayers.Request.XMLHttpRequest
 308      * Standard-compliant (W3C) cross-browser implementation of the
 309      *     XMLHttpRequest object.  From
 310      *     http://code.google.com/p/xmlhttprequest/.
 311      */
 312     OpenLayers.Request.XMLHttpRequest = cXMLHttpRequest;
 313 })();