Re: Fwd:HTTP server driven content negotiation

From: Henrik Frystyk Nielsen (
Date: Thu, Mar 18 1999

Message-Id: <>
Date: Thu, 18 Mar 1999 19:53:07 -0500
To: "Michael A. Dolan" <>, Johan Hjelm <>, Philipp Hoschka <>,
From: Henrik Frystyk Nielsen <>
Subject: Re: Fwd:HTTP server driven content negotiation

At 05:32 09/03/1999 -0800, Michael A. Dolan wrote:

>There is a client cache.  Managing the cache is exactly what this would be
>good for.   So....does this make sense?  Am I using Vary correctly?  Are
>there more examples of its use?

Sorry for the delay - my point is that if it is a end-user cache then vary
doesn't do much unless that end-user changes preferences a lot in which
case it often can be solved in more direct ways, for example if the cache
and the app exists in the same address space.

Vary really only makes sense if you have a shared cache that can serve
multiple different clients with different setup. In this case the cache has
to know under what conditions it can serve an already cached response -
this is what the Vary header field tells it.

Henrik Frystyk Nielsen,
World Wide Web Consortium