Adding support for etags in $.ajax() - and simplified the if-modified-since implement...

[jquery.git] / src / ajax.js

diff --git a/src/ajax.js b/src/ajax.js
index 4db08a4..2365387 100644 (file)
--- a/src/ajax.js
+++ b/src/ajax.js
@@ -170,6 +170,7 @@ jQuery.extend({
 
        // Last-Modified header cache for next request
        lastModified: {},
+       etag: {},
 
        ajax: function( s ) {
                // Extend the settings, but re-extend 's' so that it can be
@@ -298,10 +299,13 @@ jQuery.extend({
                        if ( s.data )
                                xhr.setRequestHeader("Content-Type", s.contentType);
 
-                       // Set the If-Modified-Since header, if ifModified mode.
-                       if ( s.ifModified )
-                               xhr.setRequestHeader("If-Modified-Since",
-                                       jQuery.lastModified[s.url] || "Thu, 01 Jan 1970 00:00:00 GMT" );
+                               // Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
+                               if ( s.ifModified ) {
+                                       if (jQuery.lastModified[s.url])
+                                               xhr.setRequestHeader("If-Modified-Since", jQuery.lastModified[s.url]);
+                                       if (jQuery.etag[s.url])
+                                               xhr.setRequestHeader("If-None-Match", jQuery.etag[s.url]);
+                               }
 
                        // Set header so the called script knows that it's an XMLHttpRequest
                        xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
@@ -363,16 +367,7 @@ jQuery.extend({
                                }
 
                                // Make sure that the request was successful or notmodified
-                               if ( status == "success" ) {
-                                       // Cache Last-Modified header, if ifModified mode.
-                                       var modRes;
-                                       try {
-                                               modRes = xhr.getResponseHeader("Last-Modified");
-                                       } catch(e) {} // swallow exception thrown by FF if header is not available
-
-                                       if ( s.ifModified && modRes )
-                                               jQuery.lastModified[s.url] = modRes;
-
+                               if ( status == "success" || status == "notmodified" ) {
                                        // JSONP handles its own success callback
                                        if ( !jsonp )
                                                success();
@@ -467,13 +462,16 @@ jQuery.extend({
 
        // Determines if an XMLHttpRequest returns NotModified
        httpNotModified: function( xhr, url ) {
-               try {
-                       var xhrRes = xhr.getResponseHeader("Last-Modified");
+               var last_modified = xhr.getResponseHeader("Last-Modified");
+               var etag = xhr.getResponseHeader("Etag");
 
-                       // Firefox always returns 200. check Last-Modified date
-                       return xhr.status == 304 || xhrRes == jQuery.lastModified[url];
-               } catch(e){}
-               return false;
+               if (last_modified) 
+                       jQuery.lastModified[url] = last_modified;
+
+               if (etag) 
+                       jQuery.etag[url] = etag;
+
+               return xhr.status == 304;
        },
 
        httpData: function( xhr, type, s ) {