Credit Card Handleing

[Chris_H]

Hello everyone.

I've been thinking about how I can have automated credit card handleing in my app.
I saw that paypal has a service where you have a <post> html field that specifies
the seller and the recipient's paypal passwords etc. and the destination script is on
paypals site, that script handles the transaction with the bank. Of course all of this
is done through encryption.

This approach by it self has major limitations, for example, I'm running a subscription
service with my app and I need to keep track of the last_time_payed field. So I was
wondering if this approach is plausible:

1# subscription renewel required -> send email to user

2# user goes to a script on my site mysite.com/payment.php?userid=832

3# the user enters the required fields, and those are encrpytedly sent to the script on my server.

4# the script on my server makes another encrypted html request to paypal's transaction script containing the transaction data.

The last step I have no idea how to do.

I'm almost completely in the dark about credit card handleing. Is there a better approach than the one above?

I'd apprechiate any help at all.

[ToonMariner]

the majorissueyou have here is secure storage of details. Essentially if you successfully completed the transaction once then you can do so again with all the same details, bar aunique transaction id. You will have to encrypt a field on the database that only you can decrypt.

[mainewoods]

paypal has a system called Instant Payment Notification (IPN) that posts data back to your server script after the paypal transaction.  It can send back lots of different data at your choosing which you could then stamp your db with.  Check with the doc on the paypal site on how to set it up, and also check some of the developer articles on that site for tutorials.

[Chris_H]

Thanks for the reply!

I'll definitely check out IPN. I wonder if paypal also has a service for automatic renewel,
I think this is what Mariner is saying. I think I'll do some more research.

If anyone can give me some advice, your more than welcome!

[utinaeniduin]

IPN is very limited.  they only allow certain variables to be passed.  i have had difficulty with the same problem.  i have a cart set up and i need name, address, items, quantity and total to be passed to a database as well as passing the total to paypal for processing.  if anyone can offer further assistance on IPN I would greatly appreciate it.