[webkit-dev] Does WebKit support 304 Not Modified for Ajax requests?

Maciej Stachowiak mjs at apple.com
Fri May 9 15:39:10 PDT 2008

On May 9, 2008, at 8:50 AM, Scott Schmitz wrote:

> I have a web application that makes extensive use of xmlhttprequest  
> (AJAX).  I have optimized these GET requests such that the server  
> will return a 304 not modified if the ETag matches up from a prior  
> request.  That way, if the browser cache already has the data, I  
> just send the header back and not the data itself.
> This works great for Firefox and Internet Explorer.  In the case of  
> those browsers, I return ETag and last modified headers for the  
> initial request.  The browser caches the data and includes
> If-Modified-Since:
> If-None-Match:
> headers when it makes a request again.  If the server determined  
> that the cache is good, it returns
> 304 not-modified response and all is good.
> WebKit and Safari do not do this.  Best I can see, the browser makes  
> its request and does not include any Etag at all.  I see this via  
> Web Inspector - Network Panel.
> Anyone know what is going on?

We support If-Modified-Since but not If-None-Match when revalidating.  
The best place to file the bug would be http://bugreport.apple.com/  
because it is actually an issue in CFNetwork, the underlying network  
library that WebKit uses (at least on the Mac and Windows ports).


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