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Drupal 8 Module Development

By : Daniel Sipos

4.3 (8)

Buy this Book

Drupal 8 Module Development

4.3 (8)

By: Daniel Sipos

Buy this Book

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.

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Free Chapter

Developing for Drupal 8

Introducing Drupal (for developers)

Developing for Drupal 8

Summary

Creating Your First Module

Creating a module

Using services in Drupal 8

Blocks

Working with links

Event Dispatcher and redirects

Summary

Logging and Mailing

Logging

Mail API

Tokens

Summary

Theming

Business logic versus presentation logic

Twig

Theme hooks

Theme hook suggestions

Render arrays

Assets and libraries

Common theme hooks

Attributes

Theming our Hello World module

Summary

Menus and Menu Links

The menu system

Rendering menus

Working with menu links

Defining local tasks

Defining local actions

Defining contextual links

Summary

Data Modeling and Storage

Different types of data storage

State API

Tempstore

UserData

Configuration

Entities

TypedData

Interacting with the Entity API

Summary

Your Own Custom Entity and Plugin Types

Custom content entity type

Drush command

Summary

The Database API

The Schema API

Running queries

Summary

Custom Fields

Field type

Field widget

Field formatter

Field settings

Using as a base field

Summary

Access Control

Introduction to the Drupal access system

Defining permissions

Checking the user credentials

Route access

Entity access

Block access

Summary

Caching

Introduction

Cacheability metadata

Placeholders and lazy building

Using the Cache API

Summary

JavaScript and the Ajax API

JavaScript in Drupal

Ajax API

Summary

Internationalization and Languages

Introduction

Internationalization

Content entities and the Translation API

Summary

Batches, Queues, and Cron

Batch powered update hooks

Batch operations

Cron

Queues

Summary

Views

Entities in Views

Exposing custom data to Views

Custom Views field

Custom Views filter

Custom Views argument

Views theming

Views hooks

Summary

Working with Files and Images

The filesystem

Stream wrappers

Managed versus unmanaged files

Using the File and Image fields

Working with managed files

Our own stream wrapper

Working with unmanaged files

Private file system

Images

Summary

Automated Testing

Testing methodologies in Drupal 8

PHPUnit

Registering tests

Unit tests

Kernel tests

Functional tests

Functional JavaScript tests

Summary

Drupal 8 Security

Cross-Site Scripting (XSS)

SQL Injection

Cross-Site Request Forgery (CSRF)

Summary

Creating Your First Module

Now that we have covered some of the introductory aspects of Drupal 8 module development, it’s time to dive right into the meat of what we are doing here--module creation.

Here are some of the important topics that we will cover in this chapter:

Creating a new Drupal 8 module--the files that are necessary to get started
Creating a route and controller
Creating and using a service
Creating a form
Creating a custom block
Working with links
Using the Event Dispatcher

Concretely, in this chapter, we will create a new custom module called Hello World. In this module, we will define a route that maps to a Controller and that outputs the age-old programming message. So, this will be our first win.

Next, we will define a service that our Controller will use to pimp up our message. After all, we don't want the same message presented to the user...