I've implemented "Buy Now" buttons for each product on my business site and can confirm that each one functions accordingly for sales and IPN. However, what I need to do is have each button redirect back to its respective product's "success" landing page after a transaction has succeeded to facilitate the presentation of a dynamically-generated instant download link. I've made a lot of headway with the system, having established a decent IPN backend that receives transaction details, records to database and emails a sales confirmation / invoice to the customer. The issue there, of course, is the IPN backend is meant to receive transaction details from paypal, not to be used as a redirect target, mostly because the data it requires to function comes directly from paypal, not from the customer's return therefrom. As I've tested that, what happens is that the IPN backend fails when arrived at as a redirect target because the customer isn't bringing with them their transaction details. So the IPN backend is called but, without the requisite transaction details, there's no way to move the customer onward from there. I've considered forcing the customer to sign in to an extent after they're returned to a default "success" landing page, using their paypal name and email credentials as a means to reference the database for the most recent transaction made by that individual, thereby accessing the IPN data and moving the customer onward to where they need to be. However, the caveat in that is a scenario in which the customer arrives at their redirect target before the IPN backend records that transaction's relevant data and the customer ends up broken down at their login attempt or, at best, provided with a link from a subsequent transaction made prior. How have you managed to work this out?
... View more