I have created a customised shopping cart coded in PHP. Once the user has filled their cart they hit checkout and all of the details, including the address detail, are posted into a PayPal shopping cart and the user can pay using a PayPal account or a credit card.
After the user has paid, PayPal re-directs (and here's the problem - see below) the user back a page on my site. This page conducts a brief to and fro with the PayPal server and, providing everything matches properly, a PDF invoice is emailed to the customer, a despatch note to the store guy and a copy invoice goes to the accounts office.
The problem: If the customer fails to return from the PayPal site then none of the order processing takes place. There are a few factors that may prevent the customer returning to the site and I need to factor this possibility in.
So, my question is, can someone tell me if I use the PayPal IPN system will it send a message to my web server 'listening' page even if the customer doesn't return to the site?
Thanks for your time,