Hobgoblin11

I am writing a listener to handle IPN notifications from paypal, and one thing I cant seemt o find anywhere - How does IPN handle pending payments, that are then completed/denied? For example, if paypal invokes my IPN once the payment is made, but pending, with a particular transaction ID, when the payment completes, does it then invoke my IPN again, with the payment status as 'completed'? If so, will this second IPN have the same transaction ID? It would seem logical that the same transaction ID is sent again, as it is actually the same customer transaction, however reading this on thepaypal website suggests otherwise: "Avoid duplicate IPN messages. Check that you have not already processed the transaction identified by the transaction ID returned in the IPN message. You may need to store transaction IDs returned by IPN messages in a file or database so that you can check for duplicates. If the transaction ID sent by PayPal is a duplicate, you should not process it again. " Help would be appreciated!!

OK, another small question - how does IPN handle pending payments? Will it call my listener again, once the payment status changes to completed, with the same details and transaction number? There doesn't seem to be much documentation on this.

Oky dokey, after a couple of days off, I've nabbed the standard Paypal listener off their site and have it working from paypal's sandbox. Obviously I need to adapt and expand it further How do I now send my custom variables, is it as simple as including a couple of lines like this in my button? <input type="hidden" name="tripid" value="<?php echo $tripid; ?>"> <input type="hidden" name="userid" value="<?php echo $userid; ?>"> Thanks a lot, your help is really appreciated!

Thanks, just trying to get my head around IPN now actually, I'll check out callback URL. Cheers

OK, I think this should belong on this board. I am trying to write something that does the following (simplified for ease of understanding): User has signed into my website and has a session variable with their user id in it. There is a table in the mySQL databse that contains details about the user. (this part is already working) User wants to pay for a trip, so clicks a customised Paypal button that takes him to the Paypal site. The item has an trip id associated with it. Once the transaction has been completed, I want to feed information back to my website, and insert the 'item id' and 'user id' into a field in a table in the database. Any idea how I might do this!? Whilst I have a basic script that will insert a row into my table, it relies on variables being sent from the page it is on, thus will not work when the user is redirected to Paypal, as I cannot find a way to send variables to paypal about the item, and then have them send it back to me once the transaction is complete. My PHP is self-taught so sorry if this way of doing things seems a bit scrappy.