Book Image

Drupal 8 Theming with Twig

By : Chaz Chumley
Book Image

Drupal 8 Theming with Twig

By: Chaz Chumley

Overview of this book

Drupal 8 is an open source content management system and powerful framework that helps deliver great websites to individuals and organizations, including non-profits, commercial, and government around the globe. This new release has been built on top of object-oriented PHP and includes more than a handful of improvements such as a better user experience, cleaner HTML5 markup, a new templating engine called Twig, multilingual capabilities, new configuration management, and effortless content authoring. Drupal 8 will quickly become the new standard for deploying content to both the web and mobile applications. However, with so many new changes, it can quickly become overwhelming knowing where to start and how to quickly. Starting from the bottom up, we will install, set up, and configure Drupal 8. We’ll navigate the Admin interface so you can learn how to work with core themes and create new custom block layouts. Walk through a real-world project to create a Twig theme from concept to completion while adopting best practices to implement CSS frameworks and JavaScript libraries. We will see just how quick and easy it is to create beautiful, responsive Drupal 8 websites while avoiding the common mistakes that many front-end developers make.
Table of Contents (20 chapters)
Drupal 8 Theming with Twig
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
Index

The role of the theme file in Drupal


Themes can be simple to compose, sometimes containing a single configuration file, a couple of Twig templates, and a few assets. However, there will be times when we need to intercept and override variables and data that Drupal outputs before them reaching our Twig templates. Drupal's API (https://api.drupal.org/api/drupal/8) allows us to create a *.theme file where we can add theme functions that can hook into the API using different types of function calls.

  • Preprocess: This is a set of function calls specific to different templates that allow us to manipulate variables before they are output to the page.

  • Hooks: This is a set of function calls to hook into the Drupal API that allows us to alter variables and override default implementations.

Preprocessors and hooks

The main role of preprocessor functions is to prepare variables to be used within our Twig templates using template_preprocess functions. These functions reference the theme and template we...