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Re: Summary of opinions on Negotiate header

From: Daniel DuBois <dan@spyglass.com>
Date: Mon, 30 Sep 1996 13:34:20 -0700
Message-Id: <>
To: Koen Holtman <koen@win.tue.nl>, Larry Masinter <masinter@parc.xerox.com>
Cc: koen@win.tue.nl, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
X-Mailing-List: <http-wg@cuckoo.hpl.hp.com> archive/latest/1667
>>So why do you need Vary: Negotiate at all? (suggestions on
>><negotiable> later).
>Here is an example.  Suppose I have variants in the languages `en' and
>`nl', and that I get
> Accept-Language: dk, *;q=0.5
>from a user agent.  Now, if the user agent is capable of transparent
>negotiation, I will send a list response (300 response), so that the
>user agent can choose the best variant itself (it may have more
>language preference information than it is sending).  If the user
>agent cannot do transparent negotiation, I will send the `en' variant
>(my `en' variant has a link to the `nl' variant in it anyway).  So in
>this case, just sending
> Vary: Accept-Language
>is not enough: the response also varies on the header which expresses
>if the user agent can negotiate.

To expand on this, suppose I make

Negotiate: dan

which says "select the best variant by adding the q values" (as opposed to
multiplying the q values like in tcn).  Even though all the Accept,
Accept-langue q's, etc, are the same, the algorithm used to select the
variant has changed, so the response does vary on Negotiate:

It's not just the data, it's the algorithm.

Daniel DuBois, Traveling Coderman         
Received on Monday, 30 September 1996 13:42:03 UTC

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