Combine PayPal/Database Scripts

Hey all, I was hoping for some general advice.

We have a small web-based game we've been running and testing, and for the future, we are interested in selling in-game items/tokens with PayPal. Essentially, these items are just numbers in a database, so I'm after some very general ideas about how to go about doing this. Can I just run a PHP script on the confirmation page after the PayPal transaction is processed? Should I put a PHP script in between confirming 开发者_JAVA百科and displaying the confirmation page? Is this even a good way to go about accomplishing this?

As this idea is relatively new, there isn't really a base of information I can find on how people are going about doing this... I'm interested in security and reliability.

Any ideas?

You don't want to just run a php script. or anyone could get ingame tokens very easily.

What you can do is send a long key to paypal. You also send a return URL that paypal hits when the transaction goes through. You tell paypal to send the key back as a parameter. You check this against your db to determine if it is a good key, then invalidate it.