I'm a little confused over the options to access external scripts. I have a custom registration design built around a trial version of my software. Customers download the software and have to run it to confirm it is compatible with their computer before they can buy. This creates a Local Machine code. I then provide a purchase link within the software which is not otherwise accessible from a store front. This link needs to offer a payment method (PayPal Pro) and then, on a successful transaction, forward the user to a script (.php) where they enter their unique Local Machine code and get a corresponding registration code in return.
To fend of freeloaders, I need to make sure people can't just type in the .php URL and enter their local machine code free of charge! Thus my current plan is to have the registration script check a Post variable to determine if the access is from a legitimate purchase or not.
This is where I get confused with eJunkie's options. http://www.e-junkie.com/ej/help.keygen.htm is about generating a custom code, but doesn't forward the user to a custom webpage where they can put in their local computer code. http://www.e-junkie.com/ej/help.redirection.htm sounds about right, where I would direct the users to a custom page. My concern here is using the GET method, the URL could be used by other people. Is there a hidden POST method I could test instead? I can't really limit each user to one registration code through a database lookup as buyers may want several copies for several machines. Then there's Send Transaction Data to a URL (http://www.e-junkie.com/ej/help.integration.htm) which also sound right, uses POST, but seems to be geared towards payment gateways, and so wouldn't operate in response to a PayPal purchase but would instead go from the buyer clicking the Pay button to my .php script without the whole payment thing.
Would you be able to advise me on the correct way to integrate my scheme? In simple terms, the steps are...
1 Customer downloads software
2 Customer runs software
3 Software generates Local Machine Code (LMC)
4 Software enables purchase button
5 Customer clicks purchase button
6 Website opens on eJunkie cart with software added (Buy Now button equivalent)
7 Buyer pays
8 Transaction complete
9 Buyer directed to custom .php page that only opens on successful purchase through eJunkie. Enters LMC and gets script generates Registration code
10 Customer enters code and software is unlocked for their LMC.
It's step 8 to 9 that I'm having trouble with. And sorry for the epic post! Hope that isn't too much information!