Cannot stop caching in IE 6

thessa

I appended ?id=jkk33434 at the end of my URL as suggested by some of the post to prevent caching from taking place but IE still caches the entire string of url together w the ??id=jkk33434.

any clues?

thessa

or to be more specific, I want to force a refresh everytime the user uses the 'Back' button to the previous page.

Weedpacket

On the manual page for [man]header[/man] are a bunch of headers that are thought to be effective at client-side and proxy caching.

thessa

I've explicitly used every header and caching still occurs. like the following


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-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', FALSE);
header('Pragma: no-cache');
session_start();

thessa

Ok, i see the difference when i call the same page on the local host, seems like the headers are recognised if page is viewed from the local server,i.e

1) The page refreshes itself when the back button is clicked

2) There is nothing found in temp internet folder

but the above charateristics is not repeating itself if the page is called from the remote server. Really in need of some expert advice.

pls help!

thessa

read this article

http://www.phpbuilder.com/tips/item.php?id=123

Seems like default headers are sent by phplib session code that confuses IE and results IE to pull from the cache, could this be the problem as I'm using session_start()?

BUT, and here's the kicker -- if you're using PHPLib session code, it will also attempt to send out some of these headers. The way in which the headers are sent is not determined by PHP -- it's determined by Apache. If your headers conflict with the PHPLib headers IE will get a confused set of headers and will pull the doc from cache. This was basically the root of my agony -- I was trying to set the headers in my code explicity, but PHPlib was sending a slightly different version of the headers. I didn't check to see what IE was finally getting, but whatever it was didn't do the trick

Don't really get what he was trying to say:

So, if you are using PHPlib, I suggest the following:

In your local.inc file where you subclass Session, overload the put_headers() method. Copy the put_headers method directly from the Session class, but add the following:

case "iehack":
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("Cache-Control: max-age=0");
header("Pragma: no-cache");
break;

just before the default: tag.

Now add the line:

var $allowcache = "iehack";

any clue to the above approach ? where is local.inc and where can i locate and modify the Session class?

dewen

we had the same problem before.

It can be solved from both server and client side.

from the server side, just use header() to send no-cache value
from the client, browser must be set to check the update everytime. Also, a proxy will cache everything on client side, so make sure, you connect without proxy

thessa

Both servers, local and internet returns the following header response without me sending any header() functions:

Array ( [0] => HTTP/1.1 200 OK [1] => Date: Thu, 16 Dec 2004 05:45:38 GMT [2] => Server: Apache [3] => Expires: Thu, 19 Nov 1981 08:52:00 GMT [4] => Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 [5] => Pragma: no-cache [6] => Set-Cookie: PHPSESSID=264758f946e181d7d627dc3954cb7126; path=/ [7] => Last-Modified: Thu, 16 Dec 2004 05:45:38 GMT [8] => Vary: Accept-Encoding,User-Agent [9] => Connection: close [10] => Content-Type: text/html )

the same dynamically generated page is not cache if sent from my local server while it caches instantly when it is sent from the internet server, both uses the same browser IE 6. any body knows why?

thessa

Just an update:

Caching is not happening in Netscape(web site works perfectly fine), but is happening in IE 6 (in two different client's browser). Both shows the same headers:

Header shown on both IE browser and Netscape 7.2:

HTTP/1.1 200 OK
Date: Wed, 22 Dec 2004 09:08:36 GMT
Server: Apache
Cache-Control: post-check=0, pre-check=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0, post-check=0, pre-check=0
Pragma: no-cache
Expires: Sat, 01 Jan 2000 00:00:00 GMT
Set-Cookie: PHPSESSID=195457f112adff03a41e8b76c73f4c13; path=/
Last-Modified: Wed, 22 Dec 2004 09:08:36 GMT
Vary: Accept-Encoding,User-Agent
Connection: close
Content-Type: text/html