header("Cache-Control: public") not working

[John]

I have read somewhere else in this newsgroup that the way to avoid the
message (Warning: Page has Expired blah, blah blah ... ) when one
presses the back button is to place the statement
header("Cache-Control: public");
at the top of the script.
I have done this but I still get the annoying message.
The session.cache_e xpire in php.ini is set to 180. I am using shared
SSL.
Thank you for you help

John

[R. Rajesh Jeba Anbiah]

Re: header("Ca che-Control: public") not working

johnmark@faster mail.com (John) wrote in message news:<1ab390bb. 0408021025.70f9 39cf@posting.go ogle.com>...[color=blue]
> I have read somewhere else in this newsgroup that the way to avoid the
> message (Warning: Page has Expired blah, blah blah ... ) when one
> presses the back button is to place the statement
> header("Cache-Control: public");
> at the top of the script.
> I have done this but I still get the annoying message.[/color]

AFAIK, for that you need to use session_cache_l imiter('private ,
must-revalidate') if you're using session.

BTW, header("Cache-Control: public") doesn't make any sense at all
(IMHO) as you have to use client cache. I guess, it might be
"private".

--
| Just another PHP saint |
Email: rrjanbiah-at-Y!com

[John]

Re: header(&quot;Ca che-Control: public&quot;) not working

ng4rrjanbiah@re diffmail.com (R. Rajesh Jeba Anbiah) wrote in message news:<abc4d8b8. 0408022349.6352 382e@posting.go ogle.com>...[color=blue]
> johnmark@faster mail.com (John) wrote in message news:<1ab390bb. 0408021025.70f9 39cf@posting.go ogle.com>...[color=green]
> > I have read somewhere else in this newsgroup that the way to avoid the
> > message (Warning: Page has Expired blah, blah blah ... ) when one
> > presses the back button is to place the statement
> > header("Cache-Control: public");
> > at the top of the script.
> > I have done this but I still get the annoying message.[/color]
>
> AFAIK, for that you need to use session_cache_l imiter('private ,
> must-revalidate') if you're using session.
>
> BTW, header("Cache-Control: public") doesn't make any sense at all
> (IMHO) as you have to use client cache. I guess, it might be
> "private".[/color]



header("Cache-Control: private") does not seem to work either

John

[R. Rajesh Jeba Anbiah]

Re: header(&quot;Ca che-Control: public&quot;) not working

johnmark@faster mail.com (John) wrote in message news:<1ab390bb. 0408031120.694e 179@posting.goo gle.com>...[color=blue][color=green][color=darkred]
> > > I have read somewhere else in this newsgroup that the way to avoid the
> > > message (Warning: Page has Expired blah, blah blah ... ) when one
> > > presses the back button is to place the statement
> > > header("Cache-Control: public");
> > > at the top of the script.
> > > I have done this but I still get the annoying message.[/color]
> >
> > AFAIK, for that you need to use session_cache_l imiter('private ,
> > must-revalidate') if you're using session.
> >
> > BTW, header("Cache-Control: public") doesn't make any sense at all
> > (IMHO) as you have to use client cache. I guess, it might be
> > "private".[/color]
>
> header("Cache-Control: private") does not seem to work either
>[/color]
What about session_cache_l imiter('private ,[color=blue]
> must-revalidate')??[/color]

--
| Just another PHP saint |
Email: rrjanbiah-at-Y!com

[John Wellesz]

Re: header(&quot;Ca che-Control: public&quot;) not working

On 02 août 2004, Sir johnmark@faster mail.com (John) claimed in
news:1ab390bb.0 408021025.70f93 9cf@posting.goo gle.com:
[color=blue]
> I have read somewhere else in this newsgroup that the way to avoid the
> message (Warning: Page has Expired blah, blah blah ... ) when one
> presses the back button is to place the statement
> header("Cache-Control: public");
> at the top of the script.
> I have done this but I still get the annoying message.
> The session.cache_e xpire in php.ini is set to 180. I am using shared
> SSL.
> Thank you for you help
>
> John[/color]


Well that's not true, you need to tell the browser that it can cache the
page so, you have to tell him that the page is valid for a certain time,

the header("Cache-Control: public"); just tell to intermediate proxies
that they are authorized to record the page in their cache.

what you need is to send headers like:

header("Cache-Control: private, max-age=3600");

##tell that it can keep the page for 1 hour in his cache (may be enough
to avoid the "page expire thing")


header("Expires : Wed, 04 Aug 2004 12:28:41 GMT");
##tell that he must check the page validity after this date

header("Last-Modified: Fri, 16 Jul 2004 22:07:59 GMT");
##tell that the page was modified on this date (used by proxies and
browsers to know if they need to recache the page or not)

so youre code would be:
<?php
$valid_date=360 0;
$the_time=time( );
$lastmodifie=fi lemtime(_SERVER["SCRIPT_FILENAM E"]);

header("Cache-Control: private, max-age=$valid_date ");
header("Expires : " . gmdate("D, d M Y H:i:s", $the_time + $valid_date) .
" GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodifie) . "
GMT");
?>