If-Modified-Since enhancement

luotonen@ptsun00.cern.ch (Ari Luotonen)
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Date: Sun, 20 Mar 1994 22:03:19 --100
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From: luotonen@ptsun00.cern.ch (Ari Luotonen)
To: Multiple recipients of list <www-talk@www0.cern.ch>
Subject: If-Modified-Since enhancement
X-Listprocessor-Version: 6.0c -- ListProcessor by Anastasios Kotsikonas
Content-Length: 620

We have currently spec'd the conditional GET to work as follows:

	GET /what/ever HTTP/1.0
	If-Modified-Since: Wednesday, 16-Mar-94 10:57:20 GMT

If /what/ever has been modified (or server doesn't support
If-Modified-Since: header) the doc is sent back normally.
However, if the doc is unchanged, server replies:

	HTTP/1.0 304 Not modified

I suggest that the rest of this response would be as if the client
(proxy) had sent a HEAD request -- this way the server can upload
a new expiry date (and other meta info) to proxy:

	HTTP/1.0 304 Not modified
	Expires: Sunday, 27-Mar-94 12:00:00 GMT

-- Cheers, Ari --