WordPress is used to drive over 40 percent of all websites online which makes the development of a plugin one of the most practically useful programming skills you can acquire. A plugin adds or alters the functionality of WordPress without altering the core code – that is, your changes continue to live on and can be reused on numerous sites. This tutorial will teach you how to write WordPress plugins starting with the basics despite having little knowledge of PHP.
What a WordPress Plugin really is.
It is best to know what a plugin is in a basic level before writing any code. A WordPress plugin is nothing more than a single or a set of PHP files which WordPress automatically finds and loads when the option is turned on. These files can integrate into the existing functionality of WordPress by using a system of actions and filters to either introduce new functionality or modify the working mechanisms.
This hook system is the way WordPress core is intended to be extended. Instead of direct editing of core files (which would be overwritten on an update), plugins install hooks to add their own code at particular points in the WordPress execution process.
This is the reason why WordPress is so adaptable. Almost anything on a WordPress site can be changed or further extended using plugins without having to do anything to the files which WordPress itself handles.
Installation of your Development Environment.
You need a local development environment to build and test plugins safely without affecting a live website. Both Local by Flywheel and XAMPP are popular versions of free products that install a complete WordPress setup on your computer.
Install a PHP code editor. The PHP Intelephense extension (Code completion syntax highlighting and error detection) on Visual Studio Code will save you lots of time.
Install a local WordPress and locate the wp-content/plugins directory. It is here that you will make your plugin folder. WordPress finds the plugins by searching this directory using php files having the necessary comment on the header of the plugin.
Writing Your Plugin File.
All WordPress plugins begin with a PHP file with a particular comment block at the top that informs WordPress of the name and information about the plugin. Open a new folder within the wp-content/plugins folder -say my-first-plugin – and within this folder, a file named my-first-plugin.php.
Include the following header at the beginning of the file:
<?php
/**
* Plugin Name: My First Plugin
* Description: This is my first WordPress plugin.
* Version: 1.0
* Author: Your Name
*/Now that you have simply this file saved WordPress will now acknowledge and display your plugin in the administration panel under Plugins. You can switch it on even though it does not do anything at all.
Learning Actions and Filters.
The two types of hooks that WordPress offers are actions and filters. Actions allow you to add code which executes at certain points in WordPress execution. Filters allow you to intercept and reverse or alter data prior to use or presentation.
In order to use add_action you can use it with the name of the hook and the name of your function. To add something to the footer of all the pages:
add_action('wp_footer', 'my_custom_footer_message');
function my_custom_footer_message() {
echo '<p>Thank you for visiting!</p>';
}Filters work similarly but your function must accept and return the modified value:
add_filter('the_content', 'add_note_to_content');
function add_note_to_content($content) {
return $content . '<p><em>This post was brought to you by My Plugin.</em></p>';
}Both these patterns will bring you surprisingly far in the development of a plugin.
The addition of Admin Pages and Settings.
A lot of the plugins require a settings page within the WordPress administration. WordPress has the capability to add pages to the admin menu and SAVO API to save and retrieve options.
Create your settings page with add_ menu page or add_ options page within an action hook of an admin menu. Now, to create data-saving forms to the WordPress database, use the Settings API functions register setting add settings section and add settings field.
Always clean up data prior to saving it and escape data prior to showing it. These are security measures necessary in the development of WordPress and are implemented in the review of the plugins during the submission to the official directory in case you submit to it.
Plugging in and testing your plug-in.
To allow debugging in WordPress in the development process, simply include define(WP_DEBUG, true) in your wp-config.php file. This shows PHP errors and warnings which would otherwise be concealed.
Another good free tool for this is the Query Monitor plugin, which displays database queries hook loaded and performance information – which will be invaluable in knowing what your plugin is doing when loading a page.
Before submitting your plugin, test it using the official WordPress Plugin Check tool to identify a typical problem with coding standards security and compatibility.
Final Thought
Understanding the process of creating WordPress plugins unlocks a tremendous potential – not only can you create custom tools to suit your personal sites, but also you can create products that you can market to millions of WordPress users around the globe. Begin with a small solution like a plugin that will address a particular issue that you face. WordPress community is large with a rich documentation and community forums to assist you through all stages.
FAQs
Q: Do I need to know PHP to develop WordPress plugins? A: Yes. PHP is the core language of WordPress plugin development. Basic PHP knowledge is sufficient to start.
Q: Can I sell WordPress plugins I develop? A: Absolutely. You can sell plugins through your own website or marketplaces like CodeCanyon. Free plugins can also be submitted to the official WordPress.org directory.
Q: How do I make my plugin compatible with the latest WordPress version? A: Test regularly against new WordPress releases use WordPress coding standards and avoid relying on deprecated functions.
Q: What is the difference between a plugin and a theme in WordPress? A: Themes control visual presentation. Plugins add functionality. The two are kept separate so functionality persists even when you change themes.
Q: How long does it take to develop a simple WordPress plugin? A: A simple plugin can be built in a few hours to a day. More complex plugins with admin interfaces and database interactions take longer.
