Key word grabber?

In PHP

[circuitjump]

Hi all,
I was just thinking of building an app with PHP. What it's supposed to do is check and see if the user that just accessed the site has been reffered from a search engine or not. If they are from an SE, then check and see what keywords they used to find us and log the site and keywords for later viewing.

How difficult will this be if at all possible?

Thanks

[sugarkane]

I've done something similar to this before. Sorry I don't have a snippet on hand, but the basic idea is:

Get the referrer using $HTTP_REFERER
use the ereg() function to check for a search engine
use ereg_replace() or preg_replace() to parse out the keywords

The biggest problem can be finding the right regex to use to get the keywords out of the referral string, but the actual script would be fairly straightforward.

[circuitjump]

Thanks for the pointers, they are gonna come in handy as soon as I start with this.