CONTENTS Foreword Introduction Chapter 1 : An Introduction to Plugins What is a Plugin? Available Plugins Advantages of Plugins Installing and Managing Plugins Summary Chapter 2 : Plugin Foundation Creating a Plugin File Sanity Practices Header Requirements Determining Paths Activate/Deactivate Functions Uninstall Methods Coding Standards 2 Plugin Development Checklist Summary Chapter 3 : Hooks Actions Filters Using Hooks from Within a Class Creating Custom Hooks How to Find Hooks Summary Chapter 4 : Integrating in WordPress Adding Menus and Submenus Creating Widgets Meta Boxes Keeping It Consistent Summary Chapter 5 : Internationalization Internationalization and Localization 3 Creating Translation Files Summary Chapter 6 : Plugin Security Securing Your Plugin User Permissions Nonces Data Validation and Sanitization Formatting SQL Statements Security Good Habits Summary Chapter 7 : Plugin Settings The Options API The Settings API The Transients API Saving Per-User Settings Storing Data in Custom Tables Summary 4 Chapter 8 : Users Working with Users Roles and Capabilities Limiting Access Customizing Roles Summary Chapter 9 : HTTP API HTTP Requests Crash Course WordPress’ HTTP Functions Practice: Reading JSON from a Remote API Practice: Sending Data to a Remote API Practice: Reading Arbitrary Content Make Your Own Plugin Repository Special Case: Fetching Remote Feeds Summary Chapter 10 : The Shortcode API Creating Shortcodes 5 Shortcode Tips Integrating Google Maps More Shortcode Quick Ideas Summary Chapter 11 : Extending Posts: Metadata, Custom Post Types, and Taxonomies Creating Custom Post Types Using Custom Post Types Post Metadata Creating Custom Taxonomies Using Custom Taxonomies A Post Type and Taxonomy Plugin Summary Chapter 12 : JavaScript and Ajax in WordPress jQuery–A Brief Introduction Ajax Adding JavaScript in WordPress Ajax in WordPress 6 Summary Chapter 13 : Cron What is Cron? Scheduling Cron Events True Cron Practical Use Summary Chapter 14 : The Rewrite API Why Rewrite URLs How WordPress Handles Queries Practical Uses Summary Chapter 15 : Multisite Differences Enabling Multisite in WordPress Multisite Functions Multisite Database Schema 7 Summary Chapter 16 : Debugging and Optimizing Supporting Old Versions (Not) Debugging Error Logging Caching Summary Chapter 17 : Marketing Your Plugin Choosing a License for Your Plugin Submitting to WordPress.org Getting Your Plugin Renowned Summary Chapter 18 : The Developer Toolbox Core as Reference Codex Tool Web Sites Community Resources 8 Tools Summary Index 9 10