Book Image

Drupal 8 Module Development - Second Edition

By : Daniel Sipos
Book Image

Drupal 8 Module Development - Second Edition

By: Daniel Sipos

Overview of this book

Drupal 8 comes with a release cycle that allows for new functionality to be added at a much faster pace. However, this also means code deprecations and changing architecture that you need to stay on top of. This book updates the first edition and includes the new functionality introduced in versions up to, and including 8.7. The book will first introduce you to the Drupal 8 architecture and its subsystems before diving into creating your first module with basic functionality. You will work with the Drupal logging and mailing systems, learn how to output data using the theme layer and work with menus and links programmatically. Then, you will learn how to work with different kinds of data storages, create custom entities, field types and leverage the Database API for lower level database queries. You will further see how to introduce JavaScript into your module, work with the various file systems and ensure the code you write works on multilingual sites. Finally, you will learn how to programmatically work with Views, write automated tests for your functionality and also write secure code in general. By the end, you will have learned how to develop your own custom module that can provide complex business solutions. And who knows, maybe you’ll even contribute it back to the Drupal community. Foreword by Dries Buytaert, founder of Drupal.
Table of Contents (20 chapters)

Attributes

In the previous three examples of theme hooks we encountered the concept of attributes in the context of using them to render HTML elements. Attributes here are understood in the same way as with HTML. For example, class, id, style, and href are all HTML element attributes. Why is this important?

The reusability of theme hooks makes it so that we cannot hardcode all our HTML attributes in the Twig template files. We can have some, including classes, but we will always need to allow business logic to inform the theme hook of certain attribute values it needs printed on the HTML element. For example, an active class on a link. This is why we have this concept of attributes.

Most theme hooks you'll see have attributes in some form or another, with the variable usually being called $attributes, $wrapper_attributes, or something of that nature. Also, this variable always...