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)

State API

The State API is a Key/Value database storage and the simplest way you can store some data in Drupal 8. One of its main purposes is to allow developers to store information that relates to the state of the system (hence the name). Also, because the state of the system can be interpreted in various ways, think of this as simple information related to the current environment (Drupal installation) that is not editorial (content), for example, a timestamp of the last time they ran or any flags or markers the system sets to keep track of its tasks. It is different from caching in that it is not meant to be cleared as often and only the code that set it is responsible for updating it.

One of the main characteristics of this system is the fact that it is not for human interaction. I mean this in the sense that it is the application itself that needs to make use of it. The option...