Re: 13.1.2 Warnings
Koen Holtman (koen@win.tue.nl)
Fri, 18 Oct 1996 11:07:18 +0200 (MET DST)
Roy T. Fielding:
>
>Ummm, is there some reason why an HTTP/1.1 user agent cannot tell
>for itself whether or not a message is stale?
Not as far as I can see. However, the warning code also gives
potentially valuable information on _why_ the message is stale. This
is why I prefer dealing with the problem when getting a warning out of
a 1.0 proxy, not when sending one to it.
The warning codes in the draft are:
10 Response is stale
11 Revalidation failed
12 Disconnected operation
13 Heuristic expiration
14 Transformation applied
Note that warning 14 is not staleness-related, so whatever else we end
up doing, we must not remove the 14 warnings when sending a response
to a 1.0 proxy.
[...]
>As a separate issue, Warning is one of the headers that should be
>listed as MUST be sent in a 304 response,
I think you are right. I recall that we updated the rules for
creating 304 (not modified) responses in a great hurry; we may have
overlooked more than just the warning stuff. (Aside: I now suspect
that the Alternates header caching rules I listed in the TCN draft are
broken too because of similar 304 compatibility subtleties.)
>.....Roy
Koen.