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Re: HTTP response version, again

From: Jeffrey Mogul <mogul@pa.dec.com>
Date: Fri, 20 Dec 96 17:05:51 PST
Message-Id: <9612210105.AA23007@acetes.pa.dec.com>
To: Ted Hardie <hardie@thornhill.arc.nasa.gov>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
    I agree that we need to resolve this, but I think that we need to
    think about the proxy/cache issue as well.  A server which responds
    with a 1.1 version advertises its capabilities to both the
    requesting user agent and any intervening proxies.

Actually, because the response version number is NOT end-to-end
(it only has meaning for a specific hop), it does advertise
the server's capabilities to the next-hop client, but not to any
subsequent client.

E.g., in this case

	origin-server -----> Proxy1 ------> Proxy2 -----> end-client

If Proxy1 sends a response to Proxy2 with
	HTTP/1.1 200 OK
then Proxy2 knows that Proxy1 supports HTTP/1.1, but it cannot
infer anything from this about the origin-server, and the end-client
cannot discover the version implemented by Proxy1.

This is my recollection of Roy Fielding's explanation from many
months ago, and I believe that this is the understanding under
which the HTTP/1.1 spec was written.  It may need to be documented,
but I think it's too late to change.

-Jeff

P.S.: not that I disagree with your overall position, Ted.
Received on Friday, 20 December 1996 17:17:59 EST

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