I've installed your plugin and I have buttons for "Buy now" links.
Next I want to hook into after the customer pays. I want to simply update 1 wp-usermeta field. I can do this in php. I need to know the userid and the product code.
Is it possible to sub class? Put a php file in an area with a certain name and have it simply append to what is already there?
The themes work this way which is great for maintainability. My mods aren't lost during an update.
I have written a very secure web service in php. There are no less than 30 checks and balances, sanitization, encryption, JSON field counts and checkes, modified crc etc.
I know a bit about programming. (Been doing mostly C / C++ for the last 30 years)
Please point me in the right direction before I waste too much time digging in.