- From: Koen Holtman <koen@win.tue.nl>
- Date: Thu, 10 Dec 1998 20:07:13 +0100 (MET)
- To: Larry Masinter <masinter@parc.xerox.com>
- Cc: mark_nottingham@exchange.au.ml.com, http-wg@hplb.hpl.hp.com
Larry Masinter: > >Mark Nottingham wrote: > >> I can't find anything in the Draft that addresses the situation when >> both Cache-Control and Pragma: no-cache headers are set, and they are in >> conflict. >> For instance, if I use >> >> Cache-Control: must-revalidate >> Pragma: no-cache >> >> on a HTTP response, it would be desireable to have it cached (and always >> revalidated) by HTTP 1.1 caches, and not cached by HTTP 1.0 caches. >> However, I can see nothing in the Draft about this, and some >> implementations, upon reading 14.32 Pragma, might never cache the >> object. While the action is safe, it's not ideal. >> >> Am I missing something somewhere? Thanks. > >The interaction of headers whose interaction is not specified >is not specified. > >An origin server cannot depend on the precedence of >"Cache-Control: must-revalidate" and "Pragma: no-cache", >and a server (1.0 or 1.1) might ignore either or both. Just to add to this: the preferred method of making responses cachable by 1.1 caches and non-cachable by 1.0 caches is to combine Cache-Control: something with Expires: <current time and date>. The interaction between these two _is_ specified. > >Larry Koen.
Received on Thursday, 10 December 1998 11:17:51 UTC