Module Development

Process Submitted Form Data via the Form Controller for Drupal 8, 9, and 10

When you create a custom form for Drupal and your module defines the form controller, the best way to handle processing of submitted data is via the submitForm() method of your controller. This method is called automatically by the Form API during the process of handling a user-submitted form. It can be used to save incoming data to the database, trigger a workflow based on user input, and instruct the Form API where to send the user after form processing has completed.

In this tutorial we'll:

  • Demonstrate how to add a submitForm() method to a form controller class
  • Access the value(s) of form input elements via the $form_state object
  • Set a redirect after performing processing in a form submission handler

By the end of this tutorial you should know how to access the values of a submitted form, and how to write custom processing code inside of the submitForm() method of a form controller.

Drupal Module Development