What will you learn
- Overview of the Form API
- The form processing life cycle
- Defining a new form controller and route
- Adding input elements to a form
- Populating form elements with default values
- Altering existing forms provided by other modules
- Validating forms and field values
- Handling submitted form data
Overview
Drupal's Form API is a framework that encompasses the HTTP form handling workflow including displaying a form, validating user input, and handling submitted data. The From API allows module developers to create, validate, and manage custom forms and alter existing ones, ensuring consistent form handling and user interaction across the site.
Drupal developer learning resources
Create forms
This course covers the Drupal Form API including; the life cycle of a form, and how to define new form controllers and routes. You will also learn how to add input elements, inject services into form controllers, and provide default values for form elements. Additionally, the course will teach you how to alter existing forms provided by other modules by implementing hook_form_alter(), retrieve and display forms, and theme forms using Twig.
Validate forms
This course covers the basics of form validation, including how to implement validation logic within form controllers, add validation callbacks to existing forms, and validate individual form elements. You will also learn how to handle errors and ensure that user input meets specific constraints before processing it further. By the end of the course, you will be able to create robust and secure forms that provide a seamless user experience while ensuring data integrity.
Process forms
This course covers how to implement the submitForm() method in form controllers to process and store data, how to use #submit callbacks to add custom processing logic to forms, and how to handle form submissions when your module does not define the form controller. By the end of the course, you will be able to effectively manage form submissions, ensuring that user input is validated, processed, and stored correctly.
Ajax
This course covers the basics of using the #ajax property in form elements, how to create dependent dropdowns that update based on user input, and how to submit forms via Ajax without requiring a page reload. You will also learn best practices for implementing Ajax in forms, including handling form validation and submission, and updating the form's display based on user interactions.
Settings and configuration forms
This course covers the basics of defining a settings form, retrieving and setting configuration values, and saving configuration data. You will also learn how to add configuration settings to themes and provide administrators with more control over the theme’s behavior.
In this related topic, you'll find both Drupalize.Me and external resources to help you along.
Forms (Form API)
TopicDrupal provides a standard, secured method for module developers to add forms to a Drupal website. Learn how to use the Form API to build, validate, and submit a custom form.
