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Re: Extension headers and caching

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 10 Feb 2009 19:08:34 +0100
Message-ID: <4991C2A2.7060205@gmx.de>
To: Eric Lawrence <ericlaw@exchange.microsoft.com>
CC: Anne van Kesteren <annevk@opera.com>, HTTP Working Group <ietf-http-wg@w3.org>

Eric Lawrence wrote:
>> IE has lots of issues with Vary
> 
> To be more specific, the WinINET networking stack does not cache outbound request headers, preventing IE and other applications from reusing resources that Vary without validation (except in narrow cases).  See http://www.fiddler2.com/fiddler/Perf/AboutVary.asp for more information.
> 
> Revalidation ensures cache-correctness but entails a performance cost.
> 
> -Eric

As far as I recall it also means that you can't pass content with Vary: 
to an external application, such as an *ics file (IE invokes the 
application with a filename of a temp file that does not exist). This is 
as of IE6, maybe it has been fixed since.

BR, Julian
Received on Tuesday, 10 February 2009 18:09:23 GMT

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