On Thu, May 05, 2005 at 08:07:15AM -0500, Mark Pilgrim wrote:
> Not to be flippant, but we have one that's widely available. It's
> called the Expires header. I spoke with Roy Fielding at Apachecon
> 2003 and asked him this exact question: "If I set an Expires header on
> a feed of now + 3 hours, does that mean that I don't want the client
> to fetch the feed again for at least 3 hours?" And he said yes,
> that's exactly what it means.
I think the problem here may be that the HTTP/1.1 spec gives the
impression that the Expires header is not designed to affect end
clients (user agents).
For instance, from 13.2.1 ("Server-Specified Expiration"), we get the
sentence:
"The expiration mechanism applies only to responses taken from a cache
and not to first-hand responses forwarded immediately to the
requesting client."
Now many clients themselves contain caches, but this distinction may
still be the source of some confusion, especially as the number of
people who know about the distinction (by having written a user agent)
compared to the number who are affected by it (by writing server
components) is pretty small.
James
--
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James Aylett xapian.org
[EMAIL PROTECTED] uncertaintydivision.org
