Professional WordPress Plugin Development

Extend WordPress with plugins using this advanced WordPress development book, updated for the current version

This significantly updated edition of Professional WordPress Plugin Development addresses modern plugin development for WordPress, the highly popular content management system (CMS). If you're using WordPress to create and manage websites, WordPress plugins are the software that can extend or enhance CMS functionality. This book offers guidance on writing plugins for WordPress sites to share or sell to other users.

The second edition of Professional WordPress Plugin Development covers the building of advanced plugin development scenarios. It discusses the plugin framework and coding standards as well as dashboards, settings, menus, and related application programming interfaces (APIs). Additional topics include security, performance, data validation, and SQL statements.

• Learn about the power of hooks in WordPress

• Discover how JavaScript and Ajax will work in your site

• Understand key technologies: Block Editor/Gutenberg, JS/React, PHP, and the REST API

• Create and use custom post types and taxonomies.

• Creating custom dashboard menus and plugin settings

• Work with users and user data

• Schedule tasks and utilizing Cron

• Performance and security considerations

Written by experienced plugin developers, Professional WordPress Plugin Development also helps you internationalize and localize your WordPress website. Find out about debugging systems and optimizing your site for speed. As WordPress use continues to increase, you can elevate your professional knowledge of how to extend WordPress through plugins.

Autorentext

About the authors Brad Williams is CEO and cofounder of WebDevStudios, a WordPress design and development firm. He is coauthor of Professional WordPress Design and Development. Justin Tadlock is a plugin and theme developer with over a decade of professional experience. He currently writes for WP Tavern. John James Jacoby has authored dozens of popular WordPress plugins and leads the development of bbPress and BuddyPress. He has contributed to every major WordPress version since 2008.

Klappentext
Required reading for WordPress plugin developers This is one of the most extensive available resources on developing plugins for WordPressthe world's most popular web content management system. The authors have prepared this updated edition, which builds from the basics of plugin development to more advanced scenarios. You'll follow a hands-on approach, with real-world examples covering situations you'll encounter as you develop custom plugins for your clients or your own sites. Additionally, you'll learn to write future-proof code that will continue to function well for years to come. Professional WordPress Plugin Development:

• Introduces you to plugin development with the WordPress plugin framework, coding standards, and hooks
• Covers essential topics in plugin development, including plugin security, scalability and performance, working with user data, and internationalization
• Reveals best practices for using advanced APIs including building custom Gutenberg block editor blocks, the REST API, and functions to extend WordPress functionality
• Describes how to code plugins using PHP, JavaScript, and modern web technologies
• Delivers tips and techniques for debugging and optimizing your new plugins, as well as guidance on releasing your plugins to the public Wrox Professional guides are planned and written by working programmers to meet the real-world needs of programmers, developers, and IT professionals. Focused and relevant, they address the issues technology professionals face every day. They provide examples, practical solutions, and expert education in new technologies, all designed to help programmers do a better job.

Inhalt
Introduction xxxi

Chapter 1: An Introduction to Plugins 1

What is a Plugin? 1

How Plugins Interact with WordPress 2

When are Plugins Loaded? 3

Available Plugins 4

Official Plugin Directory 4

Popular Plugin Examples 4

Popular Plugin Tags 5

Advantages of Plugins 5

Not Modifying Core 5

Why Reinvent the Wheel? 5

Separating Plugins and Themes 6

Easy Updates 7

Easier to Share and Reuse 7

Plugin Sandbox 7

Plugin Community 7

Installing and Managing Plugins 8

Installing a Plugin 8

Managing Plugins 9

Editing Plugins 9

Plugin Directories 9

Types of Plugins 10

Summary 11

Chapter 2: Plugin Framework 13

Requirements for Plugins 13

Naming Your Plugin 14

Using a Folder 14

Best Practices 14

Namespace Everything 14

File Organization 15

Folder Structure 16

Plugin Header 17

Creating the Header 17

Plugin License 18

Determining Paths 19

Plugin Paths 19

Local Paths 19

URL Paths 20

Activate/Deactivate Functions 22

Plugin Activation Function 22

Plugin Deactivation Function 23

Deactivate is Not Uninstall 23

Uninstall Methods 24

Why Uninstall is Necessary 24

Uninstall.php 24

Uninstall Hook 25

Coding Standards 25

Document Your Code 26

Naming Variables and Functions 27

Naming Classes and Methods 27

Naming Files 28

Single and Double Quotes 28

Indentation 28

Brace Style 29

Space Usage 29

Shorthand PHP 30

SQL Statements 30

Summary 30

Chapter 3: Dashboard And Settings 31

Adding Menus and Submenus 31

Creating a Top-Level Menu 32

Adding a Submenu 33

Adding a Menu Item to an Existing Menu 34

Plugin Settings 36

The Options API 36

Saving Options 36

Saving an Array of Options 37

Updating Options 37

Retrieving Options 38

Loading an Array of Options 39

Deleting Options 40

The Autoload Parameter 40

Segregating Plugin Options 41

Toggling the Autoload Parameter 42

The Settings API 42

Benefits of the Settings API 42

Settings API Functions 43

Creating the Plugin Administration Page 43

Registering New Settings 44

Defining Sections and Settings 44

Validating User Input 46

Rendering the Form 47

All Done! 48

Wrapping It Up: A Complete Plugin Management Page 48

Improving Feedback on Validation Errors 51

Expanding with Additional Field Types 52

Adding Fields to an Existing Page 59

How It Works 59

Adding a Section to an Existing Page 59

Adding Only Fields 60

WordPress' Sections and Setting Fields 61

User Interface Concerns 62

Removing Settings 62

Keeping It Consistent 63

Using the WordPress UI 64

Headings 64

Dashicons 64

Messages 65

Buttons 66

Form Fields 67

Tables 68

Pagination 69

Summary 70

Chapter 4: Security And Performance 71

Security Overview 72

What Securing Your Plugin is 72

What Securing Your Plugin is Not 72

User Permissions 72

How to Check current_user_can() 73

Do Not Check Too Early 73

Nonces 74

Authority vs. Intention 74

What is a Nonce? 75 <...