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Re: WGLC p6 4.2.1

From: Roy T. Fielding <fielding@gbiv.com>
Date: Tue, 19 Mar 2013 11:00:24 -0700
Cc: "IETF HTTP Working Group" <ietf-http-wg@w3.org>
Message-Id: <498FD585-41EC-4240-8562-7F28EF16F7BA@gbiv.com>
To: "Adrien W. de Croy" <adrien@qbik.com>
On Mar 17, 2013, at 3:39 PM, Adrien W. de Croy wrote:

> Hi all
> I see there were some changes made to the 3rd bullet point in 4.2.1 about selection of representations to update with a 304.
> The new text hints that dates other than those received in a previous Last-Modified can be used to generate a conditional request with If-Modified-Since. 

Yes, because that has always been allowed, including within my
original definition when I invented it in 1993.  IMS is used for
both cache updates and restricted-window traversals (e.g., MOMspider).

> However, there are a number of side-effects with introducing this concept.

It is not being introduced.  p6 was originally extracted to only talk
about the use of IMS in caching, but it still needs to deal with all
valid uses of IMS that were defined in RFC2616, RFC2068, and RFC1945.
The recent changes in p6 just restores the prior definitions.

This dual use of IMS has never been a problem in the past, though
concerns about it was one of the main reasons for introducing etags
as a replacement for validation.

Received on Tuesday, 19 March 2013 18:00:48 UTC

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