Book Image

Drupal 8 Module Development

By : Daniel Sipos
Book Image

Drupal 8 Module Development

By: Daniel Sipos

Overview of this book

Drupal is an open source web-based content management system (CMS) that can be used for building anything from simple websites to complex applications. It enables individuals and organizations to build platforms that engage users and deliver the right content at the right time. Drupal 8 is an exciting new development in the Drupal community. However, the differences from the previous version are substantial and this can put quite some pressure on Drupal 7 developers that need to catch up. This book aims to help such developers in getting up to speed with Drupal 8 module development. The book first introduces you to the Drupal 8 architecture and its subsystems before diving into creating your first module with basic functionality. Building upon that, you will cover many core APIs and functionalities available to module developers. 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. Moreover, you will learn about the Drupal 8 access system and caching layer as well as the APIs used for data processing (queues and batches). 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 of the book, you will have learned how to develop your own custom module from scratch that can help solve a small problem or even provide complex functionality. And who knows, maybe you’ll even contribute it back to the Drupal community.
Table of Contents (19 chapters)

Assets and libraries

Now that we know more about the render arrays, how they are structured and the pipeline they go through, we can talk a bit about asset management from a module development perspective, as although it is usually a theme responsibility, module developers also often have to add and use CSS and JS files to their modules, and it all happens in the render arrays.

Working with CSS and JS files has become standardized in Drupal 8 compared to its preceding version, where you had more than one way to do things. It is doing so via the concept of Libraries, which are now in Drupal 8 core and also work differently than their D7 contrib module counterpart (Libraries API). So, let's see what we have by going through some examples of making use of some CSS of JS files.

There are three steps to this process:

  1. Creating your CSS/JS file.
  2. Creating a library that includes...