magento payment process.. how it works in general

Question

got a question and I hope this is right place to ask :).. don’t quite understand how payment works in magento.

client goes to checkout and lets say wants to pay as a guest, so provides address etc. and finally gets to payment methods. Then I want clients to pay thru credit card. Already have module installed for gateway (bank?) of my choice. At that point I would expect users to be redirected to 3rd party page (bank hosted) where they giving all the details, only after being returned to my magento site with appropriate message.

In magento however it seems like they need to provide cc numbers and details on magento checkout page. I don’t understand if I (or the payment module I installed) need to transfer then all the credit card details to bank? I would have to have checkout page on ssl connection and static ip right?

The thing is I want to avoid touching CC numbers at any point and would love to have it done by a bank page. I like the idea of magento interface all the way without redirecting to another page though, the only problem is not sure if would be able to set it all up properly.

If anyone could explain to me possible options, what is the common way to do it and how the whole process works that would be very much appreciated.

I did my research and looked all over google and various forums still need someones help though. Please let me know if some parts of my question are not quite clear, will try to better explain if necessary.

Answer 1

The default architecture that Magento payment modules use involves the customer interfacing with the module and the module talking to your payment gateway behind the scenes.

Basically the customer inputs all his data (CC and all) and hits the payment button at which point certain functions are run in the chosen payment module. What these functions do is entirely up to how the payment gateway works. if the gateway talks via XML they send/receive XML, if it needs SOAP then they use SOAP and so on and so forth. This in fact is the gist of building a new payment module. Open an existing one, check out which functions are called, get rid of the code in there and substitute with your own that will talk to your particular bank/gateway.

Of course some gateways have an alternate way of operating where you send the customer to their pages, he gives them his CC data and he is promptly returned to your site. This way you don't need to worry about handling credit card data, but unfortunately the process of implementing this in Magento is somewhat more involved.

If you need to use a certain gateway then you should first check whether a payment module for it already exists. if not you can download a similar payment module, dissect it and modify it to run your code where appropriate.

Answer 2

Had to develop a payment module for DPS in NZ some time back. How this works is, you go to pay on the site and the payment module php code runs that sends off the details to an acquiring institutions payment website who process the transaction for you with the bank. In my case as I recall it was DPS NZ via some soap calls. The Soap calls contained details such as the total cost, the currency, the merchant number to identify who you are paying. The acquiring institution (DPS in this case) then takes your credit card number and expiry date and do the processing. Then, again via some soap calls back to your own magento website you get redirected back with the error code - success, etc.

DPS use soap I think, but other payment websites may use other protocols to work. The other possibility is that your credit card acquiring page could be hosted on your website and you accept the credit card numbers and do all the processing within magento to the acquirer.

In short, the process is controlled by the payment module itself. If you want to see more detail, have a look at the payment module tutorials that are available and also the comments in the magento forums. You can also look at the paypal module code.