RE: Does no_cache really deny caching?!

1999-11-16 Thread Eric Cholet

> Hello,
> 
> I would like to deny caching of pages which are under access control.
> So, I looked at no_cache and browsed through the http header
> produced by this method.
> 
> As far as I discovered, no_cache(1) behaves like the A option of
> mod_expires. The httpd header field looks like
> 
> Expires:   
> 
> I am not able to manage that all proxies set the time correclty. Most likely
> the time settings are different because only a few servers are connected
> to an NTP time source. This is even more important if a few servers
> doesn't support daylight saving time correctly.
> 
> Wouldn't it be better to behave like the M option of mod_expires, e.g.
> to set the last modification date or maybe the hard way:
> set an artificial date like 01/01/1980 (that's what I did for myself via
> $r->header_out)?!

I raised this issue on this list about a year and a half ago, and Ask
forwarded it to the Apache Group, where it was rejected because the semantics
of no_cache can't just be altered this way. You can lookup the exact reason
in the archives :-)

This works for me:

  my $headers = $r->headers_out;
  $headers->{'Pragma'} = $headers->{'Cache-control'} = 'no-cache';
  $r->no_cache(1);
 
> Steffen

--
Eric



RE: Does no_cache really deny caching?!

1999-11-16 Thread Oleg Bartunov

On Tue, 16 Nov 1999, Eric Cholet wrote:

> Date: Tue, 16 Nov 1999 17:06:30 +0100
> From: Eric Cholet <[EMAIL PROTECTED]>
> To: 'Geschke Steffen' <[EMAIL PROTECTED]>
> Cc: 'ModPerl Mail List' <[EMAIL PROTECTED]>
> Subject: RE: Does no_cache really deny caching?!
> 
> > Hello,
> > 
> > I would like to deny caching of pages which are under access control.
> > So, I looked at no_cache and browsed through the http header
> > produced by this method.
> > 
> > As far as I discovered, no_cache(1) behaves like the A option of
> > mod_expires. The httpd header field looks like
> > 
> > Expires:   
> > 
> > I am not able to manage that all proxies set the time correclty. Most likely
> > the time settings are different because only a few servers are connected
> > to an NTP time source. This is even more important if a few servers
> > doesn't support daylight saving time correctly.
> > 
> > Wouldn't it be better to behave like the M option of mod_expires, e.g.
> > to set the last modification date or maybe the hard way:
> > set an artificial date like 01/01/1980 (that's what I did for myself via
> > $r->header_out)?!
> 
> I raised this issue on this list about a year and a half ago, and Ask
> forwarded it to the Apache Group, where it was rejected because the semantics
> of no_cache can't just be altered this way. You can lookup the exact reason
> in the archives :-)
> 
> This works for me:
> 
>   my $headers = $r->headers_out;
>   $headers->{'Pragma'} = $headers->{'Cache-control'} = 'no-cache';
>   $r->no_cache(1);

I'm curious how to get this work with $r->internal_redirect ?
If I have handler /picture/random which does internal redirection
to random image (as RandPicture module from the Book) I need to
provide no_cache header to avoid caching. But I dont' know if
the above trick will works.

Regards,

Oleg

>  
> > Steffen
> 
> --
> Eric
> 

_
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: [EMAIL PROTECTED], http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83