使用IPN验证PayPal付款

Question

On my website, I want to set up a "pay to remove ads" feature, and I want to collect payments for it through PayPal. The setup that I want for this is quite simple:

1. User pays
2. Payment is verified
3. The entry in the MySQL database containing the user's information is updated to disable ads on the site for that user

To do this, I want to use PayPal's IPN service. I understand the basics of it, but I am not quite sure how to implement it, nor do I understand how I can trigger the script to update the database for the correct user. I would imagine that to do this, I need to include some means of user identification whenever they begin the payment process, but I am not sure how to do that either. I am trying to implement this in PHP.

Answer 1

The process would be:

• The user has an ID
• When he pays, you attach this ID as the custom parameter in the PayPal request
• You also define what url you want to call for the IPN
• Once the payment is complete, PayPal sends the IPN
• You verify that the actual status of the payment is "Completed"
• You retrieve the user'ID from the custom parameter
• You update your table

I hope it's clear :)