Book Image

WordPress Plugin Development Cookbook - Third Edition

By : Yannick Lefebvre
Book Image

WordPress Plugin Development Cookbook - Third Edition

By: Yannick Lefebvre

Overview of this book

WordPress is one of the most widely used, powerful, and open content management systems (CMSs). Whether you're a site owner trying to find the right extension, a developer who wants to contribute to the community, or a website developer working to fulfill a client's needs, learning how to extend WordPress' capabilities will help you to unleash its full potential. This book will help you become familiar with API functions to create secure plugins with easy-to-use administration interfaces. This third edition contains new recipes and up-to-date code samples, including new chapters on creating custom blocks for the block editor and integrating data from external sources. From one chapter to the next, you’ll learn how to create plugins of varying complexity, ranging from a few lines of code to complex extensions that provide intricate new capabilities. You'll start by using the basic mechanisms provided in WordPress to create plugins, followed by recipes covering how to design administration panels, enhance the post editor with custom fields, store custom data, and even create custom blocks. You'll safely incorporate dynamic elements into web pages using scripting languages, learn how to integrate data from external sources, and build new widgets that users will be able to add to WordPress sidebars and widget areas. By the end of this book, you will be able to create WordPress plugins to perform any task you can imagine.
Table of Contents (15 chapters)

Adding filters for custom categories to the custom post list page

A second customization method for the custom post listings is to create a drop-down box that will allow administrators to only display items that belong to a single category at a time. This can help significantly reduce the number of entries that are shown to quickly find the desired content.

Getting ready

You should have already followed the Displaying additional columns in the custom post list page recipe to have a starting point for this recipe and the resulting plugin should still be active on your development site. Alternatively, you can get the resulting code (ch4/ch4-book-reviews/ch4-book-reviews-v9.php) from the book's GitHub page and rename the file ch4-book-reviews.php.

How to do it...

Follow these steps to add a filter mechanism based on the book review type to the listings page:

  1. Navigate to the ch4-book-reviews folder of the WordPress plugins directory of your development installation...