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)

Cron

In the previous section, we created an awesome multi-request batch processing of our JSON product import. In the next section, we'll jump into the Queue API and see how we can plan the processing of multiple items at a later stage. However, before we dive into that, let's talk a bit about how the Drupal 8 cron works and what we can do with it. This is because our discussion about the Queue API is closely related to it.

First of all, Drupal doesn't actually have a fully fledged cron system. That is because it's an application and not a server capable of scheduling tasks that run at specified times of the day at intervals. However, what it does have is a cron-like system, which can come very close, especially on busy websites. Often, it is affectionately referred to as the poor man's cron. Why? Since Drupal cannot by itself do anything without any sort...