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Re: Updated Working Draft: Enabling Discovery Of Alternative Representations

From: Julian Reschke <julian.reschke@gmx.de>
Date: Fri, 23 Jun 2006 07:45:37 +0200
Message-ID: <449B8001.2080204@gmx.de>
To: "T.V Raman" <raman@google.com>
CC: paul@activemath.org, www-tag@w3.org

T.V Raman schrieb:
> Paul Libbrecht writes:
>  >  From reading such a document I get the impression that all negotiation 
>  > logic should be concentrated before a redirect in order for caches to be 
>  > enabled. Am I summarizing correctly ?
> That's an interesting observation --- and I believe that it is
> correct when one is talking about an on-device cache --- would
> but it might not be the right thing for *every* cache for
> instance, a mobile gateway might find that
> "concentrating all negotation logic" as you put it is the right
> thing since it might asume that all its accesses come from mobile
> devices. On the other-hand, a caching firewall that serves both
> mobile and desktop clients should certainly not preserve the
> results of content negotiation since it would end up serving the
> wrong representation in the following scenario:
> 0)    User-1 accesses http://example.com/info from a mobile
>       device
> 1)    caching firewall negotiates with example.com
> 2)    Serves user-1 http://example.com/info/mobile
> 3)    Later, user-2 accesses http://example.com/info through the
>       same firewall with a desktop device
> Caching the results of the content negotiation performed for
>       user-1 would be incorrect.

That's what the HTTP Vary header is for, right (see 

 > ...

Best regards, Julian
Received on Friday, 23 June 2006 05:45:47 UTC

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