Browser cache issue

danbhala

hey,

was wondering if there is a few nice lines of php code or something to lash in a .htaccess file that will force the latest copy of my web pages to the user as opposed to whats in their cahe?

I had a holding page and now i have over written it with the finished site. now for some users they have to ctrl + f5 to force a fresh download themselves...

oeb

Put this at the top of your document

[PHP]
<?php
header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past
?>
[/PHP]

danbhala

thanks, I'll test it out

p

Doing that kind of thing is a bad idea. It could affect the performance of your site quite a bit.

danbhala

even for a small site? its only 4 php pages and a few images

oeb

p wrote: »

Doing that kind of thing is a bad idea. It could affect the performance of your site quite a bit.

+1

(Just aswering his question though )

oeb

danbhala wrote: »

even for a small site? its only 4 php pages and a few images

Caching basicially means that the files are stored on a users machine and pulled from there instead of from the server. By telling the browser not to cache, the files have to be downloaded from your server.

This means more bandwidth for you, and more downloads for your visitor.

aidan_walsh

Why do you want to prevent cache searches?

p

danbhala wrote: »

even for a small site? its only 4 php pages and a few images

It's not going to make a huge difference for a site that small, but I'm guessing the reason you're asking this is because you've got a confused client

Caching works properly for normal visitors. Probably won't have a big impact on a site that small, but I still wouldn't advise it as a general practice.

danbhala

basically I had a holding page for a site thats been up for a few days. It went live this morning and got a few phone calls saying it wasnt working for them. even though it was for me because I usually ctrll + refresh to make sure I see my changes... so basically their browser was using the cache version as opposed to the live and they had no idea how to refresh it themselves

The site is only up for a week and its also a password protected and just being used internally for the company... so i'm not really concerned about bandwidth... just trying to get them off my back!

Webmonkey

danbhala wrote: »

basically I had a holding page for a site thats been up for a few days. It went live this morning and got a few phone calls saying it wasnt working for them. even though it was for me because I usually ctrll + refresh to make sure I see my changes... so basically their browser was using the cache version as opposed to the live and they had no idea how to refresh it themselves

The site is only up for a week and its also a password protected and just being used internally for the company... so i'm not really concerned about bandwidth... just trying to get them off my back!

Note that the reason some of your customers might not have being able to see it is because the holding page may have beign on a different server different webserver and it could have taken time for DNS to propagate across ISPs. It may not have being to do with cache's what so ever. Just a thought.

Edit - See it was actually cached alright (gotta read to end of posts) - some people don't know what or where the refresh button is? tut tut

Myxomatosis

Just a little tip as we're on the subject of caching.

If you ever want a browser to be forced to download a fresh copy of a page or file, e.g. a file who's contents are being dynamically changed on the server, all you have to do is append "?blah" to the end of the link / redirection.

test.php?blah 
sample.htm?blah
style.css?blah

Of course the word does not need to be blah, I usually run a random number function.
Works great no matter how many proxies or caches you are behind.