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Re: Accept headers and media parameters

From: Roy Fielding <fielding@beach.w3.org>
Date: Wed, 06 Sep 1995 14:46:13 -0400
Message-Id: <199509061846.OAA14580@beach.w3.org>
To: Jim Seidman <jim@rafiki.spyglass.com>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
>At 05:05 PM 9/2/95 -0400, Roy Fielding wrote:
>>For obvious reasons, any browser that doesn't include all the ranges
>>that it wants to accept is broken, unless it wants a 406 response instead.
>
>I think the term "range" is used incorrectly here.  The only options are
>either, "this very specific type" or "any specific type I haven't mentioned."

Media ranges are defined in the spec.  */*, text/*, and text/html
are all media ranges in that they encomapass a range of actual media types.

There are two ways to do content negotiation: preemptive or reactive.
I think preemptive content negotiation is doomed to failure in the
long term, which is why I added the 300 response code.  When the
day comes that preemptive content negotiation (Accept* headers) are
more costly than reactive (an extra round-trip carrying a URC),
then browsers and server can switch without changing the protocol.

 ....Roy T. Fielding  Department of ICS, University of California, Irvine USA
                      Visiting Scholar, MIT/LCS + World-Wide Web Consortium
                      (fielding@w3.org)                (fielding@ics.uci.edu)
Received on Wednesday, 6 September 1995 11:48:12 EDT

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