Submit your form to your database function, and from that function make a new POST request to the Payment Gateway. Here's an idea on how to POST from PHP:
With the new era of mobile computing, smartphones and tablets, wireless communications and cloud services, the USDA sought to take advantage of a mobilized workforce and the blurring lines between personal and corporate computing resources.
Nothing in an HTTP request can be trusted, including HTTP headers and form data. A form token is a tool that can be used to guard against request forgeries (CSRF). This article shows an improved approach to form tokens, making it more difficult to…