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Cache-Control and the Vary header...

From: Peter Raymond <Peter.Raymond@merant.com>
Date: Thu, 6 Sep 2001 18:16:01 +0100
Message-ID: <20CF1CE11441D411919C0008C7C5A13B027AA2FE@stalmail.eu.merant.com>
To: ietf-dav-versioning@w3.org

While reading section 8.3 of the draft I noticed that we explicitly specify
that the HTTP Vary header 
must be sent on responses to methods that take Label headers.

I assume this is because when a user does a caching operation and specifies
a Label he/she
does not want the cached response to come back if they do the same method on
the same URL
but with a different Label header or without a Label header.

But thinking along the same lines why do we not include the Depth header in
the Vary field?
A request on a URL can return different results depending on the presence or
the value of
the depth header.

Also the text in section 8.3 is wrong, it says that GET and PROPFIND are
cacheable requests
but RFC2518 (section 8.1 for example) says that the methods MUST NOT be
cached (eg
Cache-Control: no-cache).
If both GET and PROPFIND are not cacheable why have the reference to the
Vary header at all?

Peter Raymond - MERANT
Technical Architect (ADM)
Tel: +44 (0)1727 813362
Fax: +44 (0)1727 869804
WWW: http://www.merant.com
Received on Thursday, 6 September 2001 13:17:12 UTC

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