The Beginner’s Guide to WordPress Plugin Development

If you are a WordPress user, then you must be familiar with the usage of plugins. However, using plugins on your website and creating them are two separate things. If are interest in WordPress plugin development, you may be confused about where to start.

It is much easier to build your plugins than you might think. Having a solid understanding of how plugins work and how are they created is the first key step. Once you have gained thorough core knowledge about it, creating and installing your simple plugins becomes easy.

In this article, you will learn about the basics of WordPress plugin development, which includes the important elements and how they work together.

An Introduction to WordPress Plugin Development

WordPress plugins provide you with powerful methods to improve the working of your website. This also helps you to extend your site’s features apart from what’s available in the core WordPress platform, without editing any code.

There are thousands of plugins available in the WordPress Plugin Directory, therefore there is no need to develop them. Creating your plugins allows customizing the functionality of your website, which may not be available in any existing plugins.

Apart from this, plugin designing is relatively easy to learn and has greater flexibility and cost efficiency than hiring a developer to make custom additions to your site.

A plugin consists of one or more functions and files written in PHP, the primary scripting language of WordPress. It also consists of four essential elements.

How WordPress Plugins Work

If you want to develop your plugin, it’s important to first understand the working of key systems work. Plugins work by using hooks, which are defined as a method for one piece of code to interact with (‘hook into’) another.

WordPress has two types of hooks: actions and filters.

1) Actions

A WordPress action denotes a specific activity that will happen at a particular time. Using actions, allows you to add or change the functionality of your plugin. The functions that are connected to action will be executed once that action is triggered.

An example of a WordPress action is save_post. Actions are specified by the do_action function. They require the $tag parameter (the name of the action), and in some cases $args (additional arguments expanding what the action does).

WordPress core has dozens of predefined actions. You can also create your own.

2) Filters

WordPress filters are defined as hooks that are used to accept a single variable or a series of variables and then send them back after modification.

WordPress filters are created by the  apply_filters function and are defined within that function. They require the $tag (the filter name) and $value (the filtered value or variable) arguments, with the option of using $var for extra function values.

You can create your filter by using the apply_filters hook. To execute it, use the add_filter function. This will allow hooking a specific function to the filter, and allow you to manipulate the variable and return it.

Shortcodes

The shortcodes are user-facing bits of code that provide users a quick and easy method to create and show custom functionality to their sites’ visitors. Shortcodes can be inserted in posts and pages via the editor, in menus and widgets, and so on.

Most of the plugins make use of shortcodes. Create your shortcode by using the add_shortcode function. The name of your shortcode will be the first variable, and the second variable will be the output function. The output function has three values: attributes, content, and name.

Widgets

To allow plugin functionality through a simple interface is by using WordPress widgets. Create a widget by extending the WP_Widget class. WordPress makes use of an object-oriented design method for widgets, referring to the functions and values stored in the single entity of a class.

A 6-Step WordPress Plugin Development Tutorial

To add a new plugin to your website or edit any files, firstly set up a testing environment or staging site. This allows you to experiment safely, without the risk of breaking your live site.

Make sure to run test changes to your website – including new plugins – on a staging site first. #WordPressCLICK TO TWEET

Below are the six steps for developing a WordPress plugin that has been discussed in the further steps:

1) Choose a Plugin Name

2) Create Your Plugin Folder and PHP File

3) Add Your File Header

4) Program Your Plugin and Add Functions

5) Compress Your Plugin Folder

6) Activate the Plugin on Your WordPress Site

Step 1) Selecting a Plugin Name

The first step is to decide the official name for your plugin. Choose a name that is relevant to what the plugin does, but is also unique.

You can also check the WordPress Plugin Directory and indulge in a few Google searches, to make sure there are no other plugins has the same name. The official plugin name will be used for the plugin’s folder and PHP file as well.

Step 2) Create Your Plugin Folder and PHP File

After deciding on a name for your plugin, the next step is to create a folder for it.

To get started, move to the wp-content/plugins folder of your WordPress installation. Create a new folder and name it using the plugin’s name, using hyphens to separate words.

create plugin

Once the folder setup is done, the next step is to create a PHP file within it. Use the same naming convention (for example, “your-plugin-name.php”):

plugin name

Based on how complex your plugin will be, it may end up having a single PHP file or multiple files. For example, you may have separate files for language, CSS, etc.

Step 3) Add Your File Header

Once the main plugin file has been created, now, add the file header. This is a PHP block comment, which has metadata about your plugin.

Within the file, add the following code:

/**

* Plugin Name: Your Plugin Name

* Plugin URI: http://yourdomain.com

* Description: Insert a brief description of what your plugin does here.

* Version: 1.0.0

* Author: Your Name

* Author URI: http://yourdomain.com

* License: GPL2

*/

Replace the information above with the details that pertain to your plugin. Also, if your plugin directory consists of multiple PHP files, only add this header to one of them.

At a minimum, this header must have your plugin’s name. However, you can also utilize this space to add details about the author, license, etc.

After completion, save your changes. The plugin is now added to your WordPress site. Move to your WordPress admin dashboard and go to Plugins:

plugin in wordpress

Your new plugin is now listed on this screen.

Step 4) Program Your Plugin to Add Functions

Now, the basic framework for your plugin has been set up. To make it work, you’ll need to program your plugin using the elements.

There are various methods that you can use to create plugins.

It is a better option to create different files for your plugin. For example, you might set up individual files for CSS, JavaScript, images, and so on. While this isn’t necessary, it can be helpful for organization purposes, especially if your plugin does more than one thing. If you are using multiple files, add them to a compressed folder before uploading them to your site.

Step 5) Compress Your Plugin Folder

Once a PHP file is added to your WordPress plugins directory, the plugin automatically is added to your WordPress site. While writing your PHP file and plugin code, use a text or code editor.

Before uploading your plugin to your WordPress site, convert it to the .zip format. Therefore, once you’re done adding all the code you want to include, compress the plugin folder.

Step 6) Activate and Run the Plugin on Your WordPress Site

After creating the first draft of your plugin, you can use it on your WordPress site.

If the plugin is in a .zip folder, you can add it to your WordPress dashboard by going to Plugins > Add New > Upload Plugin > Choose File:

upload wordpress plugin

If the plugin was already in your WordPress directory, navigate to the Plugins screen and click on the Activate link.

WordPress Plugin Development Best Practices

There are certain tips before, during, and after WordPress plugin development, that can be helpful.

For example, while creating your plugin, be specific about the name you select. Make sure it’s unique to avoid confusion or conflict with other plugins.

Your–plugin-name. PHP file will be at the root of your plugin’s directory, with everything into sub-folders. Try to maintain your folder structure clean and simple, WordPress recommends using the following hierarchy:

plugin directory

Another helpful tip is prefixing. While prefixing your functions, prevent using the wp_ prefix. By default, WordPress code functions use this prefix, so if you are using this it can create a compatibility issue.

If you have never worked with plugins or created one from scratch, you might also consider using a WordPress plugin boilerplate to start from. This provides you with a foundation for your WordPress plugin development.

Always make plugin security a priority. It is best to protect your plugin from being susceptible to intruders.