[5625] in www-talk@info.cern.ch
HTTP format negotiation
daemon@ATHENA.MIT.EDU (Joe English)
Thu Sep 15 15:25:45 1994
Date: Thu, 15 Sep 1994 21:12:31 +0200
Errors-To: listmaster@www0.cern.ch
Errors-To: listmaster@www0.cern.ch
Reply-To: jenglish@crl.com
From: Joe English <jenglish@crl.com>
To: Multiple recipients of list <www-talk@www0.cern.ch>
Two questions regarding HTTP format negotiation:
(I remember this being asked before, but don't recall
the answer.)
1) How should a server respond to a GET request
for an object which it cannot supply in any
of the formats listed in the Accept: request
header? E.g., suppose the server can provide
/pictures/foo as image/tiff and image/jpeg,
what should it do with
GET /pictures/foo HTTP/1.0
Accept: image/gif
2) Is there any way for a client to find out what
content types are available for a given URL?
E.g., is there a header field that works like
Available-Formats: in the following:
HEAD /pictures/foo HTTP/1.0
HTTP/1.0 200 OK
Server: hypothetical/1.0
Available-Formats:
image/jpeg; length=45530; q=0.8,
image/tiff; length=120132; q=1.0
Last-Modified: Thursday, 08-Sep-94 12:00:00 GMT
3) Do any existing clients or servers actually implement
format negotiation as described in the HTTP spec?
The gopher+ protocol handles format negotiation nicely.
This is an area where HTTP seems lacking.
--Joe English
jenglish@crl.com
