Mailing-List: contact user-help@couchdb.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@couchdb.apache.org
Received-SPF: pass (athena.apache.org: domain of cmlenz@gmx.de designates
 213.165.64.20 as permitted sender)
Message-Id: <95ED0E05-515D-4E67-A3FF-D25A7B5FAD44@gmx.de>
From: Christopher Lenz <cmlenz@gmx.de>
To: user@couchdb.apache.org
In-Reply-To: <loom.20090213T115118-51@post.gmane.org>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Content-Transfer-Encoding: 7bit
Mime-Version: 1.0 (Apple Message framework v930.3)
Subject: Re: How to configure HTTP caching headers?
Date: Fri, 13 Feb 2009 15:44:00 +0100
References: <loom.20090213T115118-51@post.gmane.org>

On 13.02.2009, at 13:00, Vinay Sajip wrote:
> Just taking my first steps with CouchDB. I notice that the HTTP  
> caching headers
> currently put out cause IE (for example) to not display information  
> correctly in
> Futon. It's easy to reproduce: I open windows in Firefox and IE  
> simultaneously,
> do an update using Firefox (e.g. add a new document) and refresh the  
> IE window.
> The updated document count is not shown. If I clear the browser  
> cache and try
> again, the updated information is displayed.
>
> The HTTP header put out is
> Cache-Control: must-revalidate
>
> which seems to me insufficient - for IE, at least. Is there way of  
> configuring
> these headers, to for example
>
> Cache-Control: no-cache
> Pragma: no-cache
> Expires: some date in the past, or the same value as the Date: header

This is due to extra-aggressive (and against the HTTP spec) caching  
that IE does on XMLHTTPRequests.

A patch would need to do user agent sniffing to conditionally add the  
"cache: false" parameter to the jQuery ajax() invocations in  
jquery.couch.js (and maybe elsewhere). I wouldn't want to add this for  
all user agents, as it basically circumvents any caching for AJAX  
requests (even for not-craptastically-broken implementations), and  
thus would add quite a bit of unnecessary overhead.

Cheers,
--
Christopher Lenz
   cmlenz at gmx.de
   http://www.cmlenz.net/