I know that the recommended practice to use the custom variable of Paypal buttons is to pass an identifier which is a reference to some data in a database and then when Paypal returns a response, verified that id with its corresponding reference in the database in order to do extra processing,
But my question is, if I save data in the database when the user clicks on the Paypal button, the user gets redirect to the Paypal, how will I know that the transaction was never completed if the user clicks on the back button on his browser? Because if the user does that, I will get no response from Paypal (Completed or not). If I don't have any response from Paypal, then I just saved some data in my database for no reason.
How should I solve this issue?
I have a big form with a lot of fields, so I cannot send all that data in the custom variable since there is a limit.
Please help!
I would save them as "pending" status when they're unpaid. Then if the payment never completes you would have a record of the pending order and you could either follow up on those to try and convert them into an order or simply delete all pending orders to clean it up.