Apache (as in httpd) will set the 'Expires' header to the same value as the 'Date' header when no_cache is flagged in the request_rec. When your Perl handler sets $r->no_cache(1), mod_perl (in Apache.xs) is setting the 'Pragma: no-cache' and 'Cache-control: no-cache' headers in addition to setting the no_cache flag in the request_rec. From the code in Apache.xs, it seems like setting $r->no_cache(0) will unset the flag, but not remove the headers. -- Kyle Oppenheim Tellme Networks, Inc. http://www.tellme.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Patrick Sent: Wednesday, April 04, 2001 2:47 AM To: [EMAIL PROTECTED] Subject: no_cache & pragma/cache-control headers : confusion Dear all, There is some kind of confusion in my head, and the Eagle book seems to me even more confusing. Any help appreciated. First, I always thought that no_cache() does everything regarding headers, and that you have just to turn it on or off. However I discovered yesterday that, at least in my setup, even with no_cache(0) I have Pragma: no-cache Cache-control: no-cache which seems counter-intuitive to me. I've checked the Eagle : it says that no_cache() only adds an Expires field. Ok. But then from where does the Pragma header come ? About ->headers_out() it is specifically said : In addition, the Pragma: no-cache idiom, used to tell browsers not to cache the document, should be set indirectly using the no_cache() method. So, that seems confusing to me, since the no_cache() methods seem not to deal with Pragma headers. Who sets Pragma/Cache-control headers and why are they like that by default ? How to override that (with headers_out ?) ? TIA. -- Patrick. ``C'est un monde qui n'a pas les moyens de ne plus avoir mal.''