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Re: Cacheable extension methods (was: an idempotent idea)

From: Shel Kaphan <sjk@amazon.com>
Date: Sun, 10 Sep 1995 16:28:09 -0700
Message-Id: <199509102328.QAA06093@bert.amazon.com>
To: Roy Fielding <fielding@beach.w3.org>
Cc: http wg discussion <http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com>


The HTTP spec says (and I take this from the HTTP 1.1 spec dated
8/27/95, but it hasn't changed any time lately):

In "5.2 Method":
	"The set of common methods for HTTP/1.1 is described below
	Although this set can be easily expanded, additional methods cannot be
	assumed to share the same semantics for separately extended clients
	and servers."

This clearly implies that the spec allows that there will be some
"ad hoc" experimentation and extension of the protocol going on in the world.

People behind firewalls do not have a choice of whether their client
talks to a proxy or an origin server, so by disallowing proxies to
forward methods they do not explicitly recognize, you have made the
semantics of what happens when a method request is issued dependent on
whether you are talking to a proxy or an origin server.  

Also in "5.2 Method":
	"Servers should return ... 502 (not implemented) if the method
	is unknown or not implemented by the server".

I think an exception needs to be made for intermediate proxies.  It
seems to me they should not preemptively claim to know what the origin
server does and does not support.

--Shel
Received on Sunday, 10 September 1995 21:10:21 EDT

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