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Re: multiple Content-Encoding

From: Roy Fielding <fielding@beach.w3.org>
Date: Wed, 16 Aug 1995 15:48:40 -0400
Message-Id: <199508161948.PAA03191@beach.w3.org>
To: Dave Kristol <dmk@allegra.att.com>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
>Section 8.7 of draft-ietf-http-v10-spec-01.ps says:
>	If multiple encodings have been applied to a resource, the
>	encoding-mechanisms must be listed in the order in which they
>	were applied.
>	====
>I think this is backward.  I think they should be listed in the order
>in which they must be applied by the client in the order they're listed.
>	      ==== ==
>Consider foo.gz.Z.  Gzip was applied first, then compress.  NCSA HTTP
>1.3 produces this header:
>	Content-Encoding: x-compress, x-gzip
>(It looks like the old CERN code I have doesn't support multiple

I didn't think anyone did, but that interpretation is ugly.
Message header field values should be "added" via an append
operation.  Thus, each encoding becomes layered, and

     Content-Encoding: first
     Content-Encoding: second

has the same semantics as

     Content-Encoding: first, second

If we reverse the order, then added headers must be prepended.

 ....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, 16 August 1995 12:49:43 UTC

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