cache

edal11

I have a script that creates a thumbnail of an image (using GD) that the user uploads via the browser.
But I'm having troubles because of Cache, the thumbnail is showing the old image after uploading a new one.

I've tried to disable cache like this:

header("Expires: Mon, 26 Jul 1981 05:00:00 GMT");    // Date in the past
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
                                                     // always modified
header("Cache-Control: no-store, no-cache, must-revalidate");  // HTTP/1.1
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

and by using metatags in header:

 
<HEAD>
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE">
<META HTTP-EQUIV="Expires" CONTENT="Tue, Nov 21 2000 05:00:00 GMT">
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
</HEAD>

And I've put thesed meta's at the end after the </BODY> tag.

Does anyone know what I'm doing wrong??
Please help...

Thanks!!!! 🙂

tsinka

Hi,

the header calls must be placed at the very beginning of the script (without any output or white spaces in front of them) and the HTML meta tags must beplaced inside the head after <html>

<?PHP
header("Expires: Mon, 26 Jul 1981 05:00:00 GMT");    // Date in the past 
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
                                                     // always modified 
header("Cache-Control: no-store, no-cache, must-revalidate");  // HTTP/1.1 
header("Cache-Control: post-check=0, pre-check=0", false); 
header("Pragma: no-cache");
?>
<html>
<HEAD>
<TITLE>TheTitle</TITLE>
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE"> 
<META HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE"> 
<META HTTP-EQUIV="Expires" CONTENT="Tue, Nov 21 2000 05:00:00 GMT"> 
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> 
</HEAD>
<BODY>

edal11

Ok, I checked that, there's no output before I send headers, and I put my meta's only before the body.

This is what i was trying,

Example to expire and have no-caching of web pages in Internet Explorer:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q222064

< HTML >

< HEAD >

< META HTTP-EQUIV="REFRESH" CONTENT="5">

< TITLE> Pragma No-cache < /TITLE>

< /HEAD>

< BODY>

_ HTML code etc...

< /BODY>

< HEAD>

< META HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE" />

< META HTTP-EQUIV="EXPIRES" CONTENT="-1" />

< /HEAD>

< /HTML>

But still no luck 🙁

Any other suggestions?

edal11

Found a solution!!!

When calling your images, call them with a random number attached, trying using time():

<IMG SRC="makepic.php?<?php echo time(); ?> >

The browser will (mostly) see a "new" image URL and look at the server for it, rather than looking in cache.

I took this from here, you will have more details on this message:

http://www.phpbuilder.com/mail/php-general/2003031/1736.php

This worked perfectly!

Thanks for your reply.