src/ajax/xhr.js

   1 (function( jQuery ) {
   2
   3 var // #5280: next active xhr id and list of active xhrs' callbacks
   4         xhrId = jQuery.now(),
   5         xhrCallbacks,
   6
   7         // XHR used to determine supports properties
   8         testXHR;
   9
  10 // #5280: Internet Explorer will keep connections alive if we don't abort on unload
  11 function xhrOnUnloadAbort() {
  12         jQuery( window ).unload(function() {
  13                 // Abort all pending requests
  14                 for ( var key in xhrCallbacks ) {
  15                         xhrCallbacks[ key ]( 0, 1 );
  16                 }
  17         });
  18 }
  19
  20 // Functions to create xhrs
  21 function createStandardXHR() {
  22         try {
  23                 return new window.XMLHttpRequest();
  24         } catch( e ) {}
  25 }
  26
  27 function createActiveXHR() {
  28         try {
  29                 return new window.ActiveXObject( "Microsoft.XMLHTTP" );
  30         } catch( e ) {}
  31 }
  32
  33 // Create the request object
  34 // (This is still attached to ajaxSettings for backward compatibility)
  35 jQuery.ajaxSettings.xhr = window.ActiveXObject ?
  36         /* Microsoft failed to properly
  37          * implement the XMLHttpRequest in IE7 (can't request local files),
  38          * so we use the ActiveXObject when it is available
  39          * Additionally XMLHttpRequest can be disabled in IE7/IE8 so
  40          * we need a fallback.
  41          */
  42         function() {
  43                 return !this.isLocal && createStandardXHR() || createActiveXHR();
  44         } :
  45         // For all other browsers, use the standard XMLHttpRequest object
  46         createStandardXHR;
  47
  48 // Test if we can create an xhr object
  49 testXHR = jQuery.ajaxSettings.xhr();
  50 jQuery.support.ajax = !!testXHR;
  51
  52 // Does this browser support crossDomain XHR requests
  53 jQuery.support.cors = testXHR && ( "withCredentials" in testXHR );
  54
  55 // No need for the temporary xhr anymore
  56 testXHR = undefined;
  57
  58 // Create transport if the browser can provide an xhr
  59 if ( jQuery.support.ajax ) {
  60
  61         jQuery.ajaxTransport(function( s ) {
  62                 // Cross domain only allowed if supported through XMLHttpRequest
  63                 if ( !s.crossDomain || jQuery.support.cors ) {
  64
  65                         var callback;
  66
  67                         return {
  68                                 send: function( headers, complete ) {
  69
  70                                         // Get a new xhr
  71                                         var xhr = s.xhr(),
  72                                                 handle,
  73                                                 i;
  74
  75                                         // Open the socket
  76                                         // Passing null username, generates a login popup on Opera (#2865)
  77                                         if ( s.username ) {
  78                                                 xhr.open( s.type, s.url, s.async, s.username, s.password );
  79                                         } else {
  80                                                 xhr.open( s.type, s.url, s.async );
  81                                         }
  82
  83                                         // Apply custom fields if provided
  84                                         if ( s.xhrFields ) {
  85                                                 for ( i in s.xhrFields ) {
  86                                                         xhr[ i ] = s.xhrFields[ i ];
  87                                                 }
  88                                         }
  89
  90                                         // Override mime type if needed
  91                                         if ( s.mimeType && xhr.overrideMimeType ) {
  92                                                 xhr.overrideMimeType( s.mimeType );
  93                                         }
  94
  95                                         // X-Requested-With header
  96                                         // For cross-domain requests, seeing as conditions for a preflight are
  97                                         // akin to a jigsaw puzzle, we simply never set it to be sure.
  98                                         // (it can always be set on a per-request basis or even using ajaxSetup)
  99                                         // For same-domain requests, won't change header if already provided.
 100                                         if ( !s.crossDomain && !headers["X-Requested-With"] ) {
 101                                                 headers[ "X-Requested-With" ] = "XMLHttpRequest";
 102                                         }
 103
 104                                         // Need an extra try/catch for cross domain requests in Firefox 3
 105                                         try {
 106                                                 for ( i in headers ) {
 107                                                         xhr.setRequestHeader( i, headers[ i ] );
 108                                                 }
 109                                         } catch( _ ) {}
 110
 111                                         // Do send the request
 112                                         // This may raise an exception which is actually
 113                                         // handled in jQuery.ajax (so no try/catch here)
 114                                         xhr.send( ( s.hasContent && s.data ) || null );
 115
 116                                         // Listener
 117                                         callback = function( _, isAbort ) {
 118
 119                                                 var status,
 120                                                         statusText,
 121                                                         responseHeaders,
 122                                                         responses,
 123                                                         xml;
 124
 125                                                 // Firefox throws exceptions when accessing properties
 126                                                 // of an xhr when a network error occured
 127                                                 // http://helpful.knobs-dials.com/index.php/Component_returned_failure_code:_0x80040111_(NS_ERROR_NOT_AVAILABLE)
 128                                                 try {
 129
 130                                                         // Was never called and is aborted or complete
 131                                                         if ( callback && ( isAbort || xhr.readyState === 4 ) ) {
 132
 133                                                                 // Only called once
 134                                                                 callback = undefined;
 135
 136                                                                 // Do not keep as active anymore
 137                                                                 if ( handle ) {
 138                                                                         xhr.onreadystatechange = jQuery.noop;
 139                                                                         delete xhrCallbacks[ handle ];
 140                                                                 }
 141
 142                                                                 // If it's an abort
 143                                                                 if ( isAbort ) {
 144                                                                         // Abort it manually if needed
 145                                                                         if ( xhr.readyState !== 4 ) {
 146                                                                                 xhr.abort();
 147                                                                         }
 148                                                                 } else {
 149                                                                         status = xhr.status;
 150                                                                         responseHeaders = xhr.getAllResponseHeaders();
 151                                                                         responses = {};
 152                                                                         xml = xhr.responseXML;
 153
 154                                                                         // Construct response list
 155                                                                         if ( xml && xml.documentElement /* #4958 */ ) {
 156                                                                                 responses.xml = xml;
 157                                                                         }
 158                                                                         responses.text = xhr.responseText;
 159
 160                                                                         // Firefox throws an exception when accessing
 161                                                                         // statusText for faulty cross-domain requests
 162                                                                         try {
 163                                                                                 statusText = xhr.statusText;
 164                                                                         } catch( e ) {
 165                                                                                 // We normalize with Webkit giving an empty statusText
 166                                                                                 statusText = "";
 167                                                                         }
 168
 169                                                                         // Filter status for non standard behaviors
 170
 171                                                                         // If the request is local and we have data: assume a success
 172                                                                         // (success with no data won't get notified, that's the best we
 173                                                                         // can do given current implementations)
 174                                                                         if ( !status && s.isLocal && !s.crossDomain ) {
 175                                                                                 status = responses.text ? 200 : 404;
 176                                                                         // IE - #1450: sometimes returns 1223 when it should be 204
 177                                                                         } else if ( status === 1223 ) {
 178                                                                                 status = 204;
 179                                                                         }
 180                                                                 }
 181                                                         }
 182                                                 } catch( firefoxAccessException ) {
 183                                                         if ( !isAbort ) {
 184                                                                 complete( -1, firefoxAccessException );
 185                                                         }
 186                                                 }
 187
 188                                                 // Call complete if needed
 189                                                 if ( responses ) {
 190                                                         complete( status, statusText, responses, responseHeaders );
 191                                                 }
 192                                         };
 193
 194                                         // if we're in sync mode or it's in cache
 195                                         // and has been retrieved directly (IE6 & IE7)
 196                                         // we need to manually fire the callback
 197                                         if ( !s.async || xhr.readyState === 4 ) {
 198                                                 callback();
 199                                         } else {
 200                                                 // Create the active xhrs callbacks list if needed
 201                                                 // and attach the unload handler
 202                                                 if ( !xhrCallbacks ) {
 203                                                         xhrCallbacks = {};
 204                                                         xhrOnUnloadAbort();
 205                                                 }
 206                                                 // Add to list of active xhrs callbacks
 207                                                 handle = xhrId++;
 208                                                 xhr.onreadystatechange = xhrCallbacks[ handle ] = callback;
 209                                         }
 210                                 },
 211
 212                                 abort: function() {
 213                                         if ( callback ) {
 214                                                 callback(0,1);
 215                                         }
 216                                 }
 217                         };
 218                 }
 219         });
 220 }
 221
 222 })( jQuery );