title: Http caching - check for file change works with html but not with xml - Chrome
body: <p>I have two files which I would like to cache client side untill the origin changes. </p>
  
  <p>The call to the html page (index.html) has following headers in the response:</p>
  
  <pre><code>HTTP/1.1 200 OK
  Cache-Control: public,max-age=7776000
  Content-Type: text/plain
  Content-Encoding: gzip
  Last-Modified: Wed, 13 Jul 2011 13:02:04 GMT
  Accept-Ranges: bytes
  ETag: "e07f1e105d41cc1:0"
  Vary: Accept-Encoding
  Server: Microsoft-IIS/7.5
  X-Powered-By: ASP.NET
  Date: Wed, 03 Aug 2011 11:47:47 GMT
  Content-Length: 242
  </code></pre>
  
  <p>The call to the xml page (application-context-dashboard.xml) has following headers in the response:</p>
  
  <pre><code>HTTP/1.1 200 OK
  Cache-Control: public,max-age=7776000
  Content-Type: text/xml
  Content-Encoding: gzip
  Last-Modified: Wed, 03 Aug 2011 11:31:56 GMT
  Accept-Ranges: bytes
  ETag: "10ba5f3d051cc1:0"
  Vary: Accept-Encoding
  Server: Microsoft-IIS/7.5
  X-Powered-By: ASP.NET
  Date: Wed, 03 Aug 2011 11:47:14 GMT
  Content-Length: 457
  </code></pre>
  
  <p>Now, when I reload them, for the index.html, a 304 is sent to check whether the file has changed. For the xml file no 304 is sent and client cache is triggered.</p>
  
  <p>304 call for index.html:
  Request:</p>
  
  <pre><code>GET /edumatic3/trunk/backend/index.html HTTP/1.1
  Host: localhost
  Connection: keep-alive
  Cache-Control: max-age=0
  User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.122 Safari/534.30
  Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
  Accept-Encoding: gzip,deflate,sdch
  Accept-Language: nl,en-US;q=0.8,en;q=0.6,fr;q=0.4
  Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
  Cookie: CurrenUICulture=en-us
  If-None-Match: "e8626a973e45cc1:0"
  If-Modified-Since: Mon, 18 Jul 2011 11:34:01 GMT
  </code></pre>
  
  <p>Is there a way to achieve the same result for the xml file? + Why does it work for html and not for xml? The two headers for the initial request seem to be identical.</p>
  
  <p>Browser: Chrome.</p>
  
  <p>Same problem for other static content like swf, txt, ...</p>
  
  <p>UPDATE:</p>
  
  <p>Apparently Chrome does an OK job for the index.html, but firefox for instance does not...</p>