Refreshing / Reloading a web page to clear the cache

lisabee

I have a edit program that enables a user to maintain a record within a database. One of the fields in the record is an image; however, the image is actually being uploaded to a directory instead of within the database (with a pointer in the database linking to the image in the directory).

Since my program 'hard codes' the image name when the image is uploaded a caching problem occurs when the image is replaced via a new upload because it uses the same image name. After the replacement occurs the page is reloaded using a header() function in order to redisplay the record information and show that the replacement has occurred.

Anyways, what happens is that the 'old' image is displayed until the Refresh button is clicked; then the new image shows up indicating the image was replaced correctly but the browser is first showing the cached image instead of getting the new image from the server.

Now for my question....how can I force the browser to do the same thing as clicking the refresh button as I redirect / reload the page after the image replacement occurs?

I have tried echoing Javascript using history.go(0) and location.reload()...both send the browser into an infinite loop. I have also tried the following:

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

But all to no avail. Can anybody help?

😕

chyan

open your php.ini configuration
and point to "session Cache Limiter"
there is 3 choice "nocache , private and public"
you must set it to "no cache"

lisabee

Thanks Chyan, I'll give it a try. 🙂

zzz

I have the exact same issue. I have access to my php.inio, but before I go ahead and tweak it one question:

Is it a good tradeoff?

Currently I need to refresh teh image only when a user updates it.
If I change the settings in php.ini won't this be slowing down my entire site because cache will be disabled and ALL files will be requested from the server?

zzz

Well, apparently my php.ini is already set to nocache...

I'm still having problems then. I've attempted to use the following on top of my document, wihout any luck:

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 

// HTTP/1.1 
header("Cache-Control: no-store, no-cache, must-revalidate"); 
header("Cache-Control: post-check=0, pre-check=0", false); 

// HTTP/1.0 
header("Pragma: no-cache");

lisabee

Hi ZZZ, I was unable to resolve the issue I posted...I ran into the same things you are running into. Since the problem was occuring with my client using their 'backend' database maintenance program, I just advised them to 'refresh' after they upload. Kind of a hassle, but it is working for them until I discover a better solution.

Maybe someone will come across the postings soon who will be able to give us the solutions we are looking for. Sorry I couldn't help. :queasy: