Preface

Developing plugins for WordPress is the next big thing for you if you are an administrator looking to enhance a personal site with custom functionality for which no plugin exists, a developer looking to enhance the WordPress platform with new ideas for the community, or a website designer building a specific project for a client. Learning how to create WordPress plugins will allow you to unleash the full potential of the most popular web content management system.

As an early WordPress adopter, before version 1.0 was out, I started building plugins to add functionality to my personal site. Once I got these new elements in place, I quickly realized that other users could benefit from these extensions, and started distributing them online. To this day, I always love hearing back from users of my creations and finding out how they have put them to use and what new functionality they think would make them even better.

While developing plugins might initially sound a little bit like black magic, this book shows you how easy creating plugins actually is through a series of step-by-step recipes. If you have previously added code to a theme's functions file, you may even be familiar with some of the mechanics explained in this book. With all of the information contained in this book, you will quickly be able to create your own plugins or dissect existing ones to add that extra bit of missing functionality that you require. Before you know, you'll be publishing your own creations to the official WordPress plugin repository!

Let's start learning how to cook up great WordPress plugins!

What this book covers

Chapter 1, Preparing a Local Development Environment, shows plugin developers how to install and configure an efficient development environment.

Chapter 2, Plugin Framework Basics, explains the basic mechanics of registering user functions with WordPress to be executed at key points when web pages are displayed, forming the basis of plugin creation.

Chapter 3, User Settings and Administration Pages, covers the creation of administration pages that will allow users to configure the plugins you create.

Chapter 4, The Power of Custom Post Types, empowers developers to add whole new content management sections to the WordPress environment.

Chapter 5, Customizing Post and Page Editors, demonstrates how to alter the default administration post and page editing environment to add new capabilities.

Chapter 6, Accepting User Content Submissions, allows users to submit their own content to new content sections that will be managed by your plugins.

Chapter 7, Customizing User Data, explains how to store additional information for users and how to modify site output based on this data.

Chapter 8, Creating Custom MySQL Database Tables, leverages the power of MySQL to create custom database tables in a site database to store and retrieve custom data.

Chapter 9, Leveraging JavaScript, jQuery, and AJAX Scripts, makes plugin output very dynamic by using a number of popular script libraries.

Chapter 10, Adding New Widgets to the WordPress Library, indicates how to add new widgets that users will be able to easily drag and drop to add content to their web pages.

Chapter 11, Enabling Plugin Internationalization, prepares your plugin to be translated into any language to make it easier to be used by non-English speakers.

Chapter 12, Distributing Your Plugin on wordpress.org, shows you how to prepare your plugin for sharing with the global WordPress community.

What you need for this book

Chapter 1, Preparing a Local Development Environment, walks you through all of the tools that are useful to have when developing plugins for WordPress, including a local web server, a Subversion client, and a dedicated code editor. While this book will always describe all of the steps necessary to perform its recipes, having a good understanding of WordPress will allow you to fully appreciate the information contained in these pages.

Who this book is for

This book is for WordPress users, developers, or site integrators with basic knowledge of WordPress and PHP and an interest in creating new plugins to address their personal needs, client needs, or share new ideas with the WordPress community.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "create a text file called uninstall.php in the ch8-bug-tracker directory and open it in a code editor."

A block of code is set as follows:

add_filter( 'the_generator', 'ch2gf_generator_filter', 10, 2 );

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

 echo '<tr style="background: #FFF">'; 
 echo '<td><input type="checkbox" name="bugs[]" value="'; 
 echo intval( $bug_item['bug_id'] ) . '" /></td>';
 echo '<td>' . $bug_item['bug_id'] . '</td>';

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Here, we added an inner grid with two full-size columns; one for the Price of an item and the other will wrap up the Quantity component."

Note

Warnings or important notes appear in a box like this.

Note

Tips and tricks appear like this.

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Questions

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