- From: Henrik Frystyk Nielsen <frystyk@w3.org>
- Date: Tue, 08 Jul 1997 14:31:59 -0400
- To: Koen Holtman <koen@win.tue.nl>
- Cc: http-wg@cuckoo.hpl.hp.com
At 10:04 PM 7/7/97 +0200, Koen Holtman wrote: >>An HTTP/1.1 server MUST include a Vary header field with any cachable > ^^^ > why did you leave out `an appropriate'? I think that leaving this > out makes the text worse. `an appropriate' signals that is the > responsibility of server to ensure that the client does the right > thing based on the vary header field contents. To me, "appropriate" doesn't make a lot of sense in a spec - it is a nothing but a fill word. The whole spec is about describing the "right thing" or what's appropriate compared to what is "unappropriate", "bogus" or "brain dead". >>response that is subject to server-driven negotiation. Doing so allows a >>cache to properly interpret future requests on that resource and informs >>the user agent about the presence of negotiation on that resource. A server >>SHOULD include a Vary header field with a non-cachable response that is >>subject to server-driven negotiation, since this might provide the user >>agent with useful information about the dimensions over which the response >>vary at the time of the response. > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Again, I liked the old text better. The addition of `at the time of the > response' only begs questions which need not be answered. There is an important note to this in that it points out how the vary header allows a cache to handle _future_ requests based on what a server knows _at the time_ of the response. This was one of the things that was confusing in the current wording in the spec. The time of the response is well-defined - it's the time at which the message was originated and which may be put into a Date header. This is described in section 14.19. Thanks, Henrik -- Henrik Frystyk Nielsen, <frystyk@w3.org> World Wide Web Consortium http://www.w3.org/People/Frystyk
Received on Tuesday, 8 July 1997 11:35:58 UTC