New header function behaviour in PHP4 ??
| From: | Graham Isted | Date: | Tue, 20 Jun 2000 09:48:19 +0000 |
| Subject: | New header function behaviour in PHP4 ?? | ||
| Groups: | php.general | ||
| Request: | Send a blank email to php-general+get-2285@lists.php.net to get a copy of this message | ||
Hi
I've been writing a shop using PHP / PHPLIB / APACHE, developing on Windows for a BSD server.
I recently upgraded to PHP4 on my Windows machine, but my server provider is still at PHP3.
I have noticed what I think is difference to the HEADER function behaviour in PHP4:
I didn't want any of my pages to be cached, so I've set the PHPLIB session to
allowcache=no, which at version 7.2b sends the following HTTP cache-related HEADERS:
default:
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-cache");
header("Cache-Control: post-check=0, pre-check=0");
header("Pragma: no-cache");
break;
In PHP4, this works fine, but using IE5 on PHP3 on the server, when I go BACK on the browser then IE
gets the page from cache, despite the expiry date being in the past.
The cache-related headers which I see returned if I Telnet to the relevant hosts are:
FOR PHP3:
Expires: Mon, 26 Jul 1997 05:00:00 GMT
Last-Modified: Mon, 19 Jun 2000 09:59:38 GMT
Cache-Control: post-check=0, pre-check=0
Pragma: no-cache
FOR PHP4:
Cache-Control: no-cache, post-check=0, pre-check=0
Expires: Mon, 26 Jul 1997 05:00:00 GMT
Pragma: no-cache
Last-Modified: Mon, 19 Jun 2000 10:18:16 GMT
I found I could get round this problem on IE5 on PHP3 by changing PHPLIB session.inc to:
default:
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-cache");
# header("Cache-Control: post-check=0, pre-check=0");
header("Pragma: no-cache");
break;
... or ....
default:
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
# header("Cache-Control: no-cache");
header("Cache-Control: no-cache, post-check=0, pre-check=0");
header("Pragma: no-cache");
break;
When I use the latter of the above variants, the returned cache-related headers are:
FOR PHP3
Expires: Mon, 26 Jul 1997 05:00:00 GMT
Last-Modified: Tue, 20 Jun 2000 08:43:40 GMT
Cache-Control: no-cache, post-check=0, pre-check=0
Pragma: no-cache
(only change is of course the addition of NO-CACHE in the Cache-Control header)
FOR PHP4
Cache-Control: no-cache, post-check=0, pre-check=0
Expires: Mon, 26 Jul 1997 05:00:00 GMT
Pragma: no-cache
Last-Modified: Mon, 20 Jun 2000 08:57:00 GMT
(ie no change)
I would have to assume therefore, that PHP4's HEADER function is behaving differently from that
in PHP3 (perhaps it is concatenating Cache-Control statements where there is more than one!?)
Can someone from the PHP Dev team possibly clarify exactly what the internals of the HEADER function
do
Thanks
GRAHAM ISTED