Re: want to set my pages to expire but can't find info on date format expected ... from Roy T. Fielding on 1999-05-22 (ietf-http-wg@w3.org from April to June 1999)

From: Roy T. Fielding <fielding@kiwi.ics.uci.edu>
Date: Sat, 22 May 1999 15:17:11 -0700
To: John Stracke <francis@ecal.com>
cc: http-wg@cuckoo.hpl.hp.com
Message-ID: <9905221517.aa16117@paris.ics.uci.edu>

>Naive question: can you specify Max-Age on a 1.1 response and Expires on a
>1.0 response? Or are you likely to run into problems with proxies giving the
>1.1 response to 1.0 clients? (I know they're not supposed to.)

Both are 1.x header fields.  If the recipient understands cache-control
and max-age, then it will ignore Expires.  Otherwise, it will ignore the
cache-control.  Therefore, it is best to send both.

There is nothing wrong with sending an HTTP/1.1 response to an HTTP/1.0
client.  There are some features of HTTP/1.1 that cannot be used with
an HTTP/1.0 client, but that's different (and aren't related to caching).

....Roy

Received on Saturday, 22 May 1999 15:27:13 UTC