W3C home > Mailing lists > Public > ietf-http-wg-old@w3.org > September to December 1999

Re: Clarification on cacheability

From: Roy T. Fielding <fielding@kiwi.ICS.UCI.EDU>
Date: Wed, 22 Dec 1999 14:34:45 -0800
To: "Josh Cohen (Exchange)" <joshco@exchange.microsoft.com>
cc: "HTTP-WG (E-mail)" <http-wg@hplb.hpl.hp.com>
Message-ID: <199912221434.aa00526@gremlin-relay.ics.uci.edu>
>So, what do you mean by that?  SHould they re-use a 3xx code that allows
>caching ? Which of those would be best ? 
>The idea of using 305 Use proxy came up, what do you think of that?

I'd just define a new 3xx code and use that.

>In regard to your 206 rationale..
>The 206 is a clear case of why you dont want to cache, but by default
>it wouldnt be.  Actively adding cache-control would instruct the cache to
>cache it.  However, that would be broken, thus you shouldnt send cache
>control

No, you are confusing the requirements.  A cache that doesn't understand 206
won't cache it because of the MUST NOT on unrecognized codes.  A cache
that does understand 206 will look at the cache-control field.

These are forward-looking requirements: we don't know what the semantics
of the new code may be, and this is the only way to specify proper handling
of future sementics in the presence of intermediary caches.

I think the WAP folks are confused in any case -- it would be foolish to
mark a client-specific redirection response as cacheable by anything
less than a fully-compliant 1.1 proxy with Vary, which itself is so rare
that they should just assume that their new code will be understood by
any cache that might gain from caching it.

....Roy
Received on Wednesday, 22 December 1999 22:35:52 EST

This archive was generated by hypermail pre-2.1.9 : Wednesday, 24 September 2003 06:33:34 EDT