2 times callback from payment gateway

[Keen]

Hi,

I have written a payment gateway. Sometimes the PSP gives a callback 2 times.
Therefore 2 income records are created.
Is there a way to solve this?

Thanks

[netshine]

Firstly I would try to determine why they send 2 callbacks. Are the 2 callbacks identical? Paypal for example, will sometimes send 2 IPN callbacks - one for confirming the payment, and another to confirm the subscription has been set up. As nBill is only interested in the payment, the gateway script checks the parameters sent by the PSP and discards the unwanted callback. If the parameters being sent to you by the PSP are identical in both cases, you should probably contact the PSP and ask why. In any case, you could make a record in the database that a callback has been received for a given g_tx_id, so that you can discard any duplicates.