How do I set session variables in a custom php file in Drupal?

Question

In a subpage on my drupal site I have a form. I'd like the form to post to a simple process.php file, that takes the form data and then sets a $_SESSION variable and returns the user to the original page.

Currently the process.php file is not seeing the $_SESSION vars set in standard drupal pages and viceversa, drupal pages don't see the $_SESSION vars set in the process.php file, they act as if they are on completely different sites. What am i missing?

Answer 1

From my research it looks like the only way to set session variables and run your own php code is to create a module.

I've looked at the Drupal.org tutorial here: https://www.drupal.org/developing/modules and this one here: http://www.wdtutorials.com/2012/04/29/drupal-7-how-create-module-part-1

Lastly, I'd also recommend looking at existing modules and learning from those as well.