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Which usual media types can a server send

From: Owen Rees <rtor@ansa.co.uk>
Date: Fri, 17 Mar 1995 17:48:59 +0000
Message-Id: <9503171749.AA01191@plato.ansa.co.uk>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
In section 5.4.1 of draft-ietf-http-v10-spec-00, it says that "*/*" means all 
media types but then goes on to imply that this excludes "unusual" media 
types. It then goes on to suggest that the definition of unusual should be a 
configurable aspect of the user agent.

Since the server can have no way of knowing what the client/user agent has 
been configured to consider "unusual", it is forced to treat "*/*" not as 
"all" but as "don't know". The server must therefore use its own definition of 
"unusual" in determining whether or not a media type is acceptable. This seems 
to be undermining the whole purpose of the Accept header.

Having "*/*" really mean "all", and this being the default, does create the 
problem that a server can send an x-perimental/bizzare entity without a 
content-length on the grounds that it is self-describing. If the server keeps 
the connection open waiting for the next request, and the client does not 
recognise that it has all of the entity then we have a deadlock.

I do not like having */* potentially mean different things to each individual 
client and server. Here are some other options to consider:

1) */* does not mean all, it means some specified set of media types
2) */* is not the default; some specified set of media types is the default
3) */* is the default and really means all - live with the possible deadlock

I am not particularly happy with any of these, but I think that the 
uncertainty about the meaning of */* is worse.

Regards,
  Owen Rees <rtor@ansa.co.uk>
Information about ANSA is at <URL:http://www.ansa.co.uk/>.
Received on Friday, 17 March 1995 10:00:14 EST

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