6 Apr 2021

WordPress Introduction

WordPress Introduction to WordPress Plugin Development. You’ll learn all the critical points of WordPress plugin development in this course, everything from creating your first plugin project to registering widgets and shortcodes. After following this course, you’ll be all set to develop your custom plugins for WordPress.

All WordPress site demands a theme to pull content from the database and display that in a design. And apparently, you could run a site with just a piece and nothing different. But that site would be the smallest without the addition of plugins.

Plugins add extra functionality to your WordPress site above and above what comes with the WordPress core. Everything from a booking calendar or animated slider to a full-featured learning administration system or online marketplace—you can add them all to your site with plugins.

In this guide, I’ll show you how to create your WordPress plugin. I’ll show you how to use best practices in plugin development, get the code in your plugin to run, and structure your plugin’s code and files

What is a Plugin?

Plugins are groupings of code that extend the core functionality of WordPress.

By creating your plugin, you are extending WordPress, i.e., building added functionality on top of everything WordPress already offers. For case, you could write a plugin that displays links to your site’s ten various recent posts.

Or, using WordPress’s custom post types, you could write a plugin that generates a full-featured support ticketing system with email notifications, custom ticket statuses, and a client-facing portal. The opportunities are endless!

Most WordPress plugins are made of many files, but a plugin only requires one main file with a specifically formatted DocBlock in the header.

Hello Dolly, one of the first plugins is only 82 lines long. Hello, Dolly shows lyrics from the famous song in the WordPress admin.

As a WordPress.org plugin author, you have a fantastic opportunity to create a plugin that will be installed, tinkered with, and loved by millions of WordPress users. All you need to do is turn your great design into code. The Plugin Handbook is here to advise you with that.

Plugin Basics

To its simplest, a WordPress plugin is a PHP file with a  plugin header commentary.

To start creating a new plugin, follow the steps below.

  1. Navigate to the WordPress installation’s wp-content directory.
  2. Open the plugins directory.
  3. Please create a new guide and name it after the plugin (e.g., plugin-name).
  4. Open the new plugin’s directory.
  5. Please create a new PHP file (it’s also good to name this file after your plugin, e.g., plugin-name.php).

WORDPRESS Plugin Security

Hear, your code works! But is it safe? How will the plugin protect your users if their site gets hacked? The best plugins in the  directory keep their users’ information safe.

Please keep in mind that your code may be running across hundreds, perhaps even millions, of websites, so security is of the utmost importance.

This chapter will cover how to check user capabilities, validate and sanitize input, sanitize output, and create and validate nonces.

Hooks WordPress

Hooks are processes for one piece of code to interact/modify another part of code at specific, pre-defined spots. They make up the foundation for how plugins and themes interact with  Core, but they also use extensively by Core itself.

There are two kinds of hooks: Actions and Filters. To use both, you need to write a method function known as a Callback and then register it with a  hook for a specific action or filter.

Actions vs. Filters #Actions vs. Filters

The main difference between an action and a filter can be summed up like this:

  • The action takes the info it receives, does something with it, and returns nothing. In other words: it acts on something and then exits, yielding nothing to the calling hook.
  • A filter takes the info it collects, modifies it somehow, and returns it. In other words: it cleans something and passes it back to the hook for further use.

Said another way:

  • an action prevents the code flow to do something and later returns to the normal flow without modifying anything;
  • a filter is used to change something in a specific way so that the change is then used by code later on.

WORDPRESS Administration Menus

Administration Menus obtain the interfaces displayed in  Administration. All allow you to add options pages for your plugin.

Top-Level Menus and Sub-Menus

The Top-level menus exist rendered along the left side of the  Administration. All menus may include a set of Sub-menus.

When choosing between Top-level menus and Sub-menus, think carefully about the needs of your plugin as well as the needs of your end-users.

WORDPRESS Shortcodes

As security regard, running PHP inside WordPress content is forbidden; to provide dynamic interactions with the content, Shortcodes were presented in  version 2.5.

Shortcodes mean macros that can be used to perform dynamic communications with the content—i.e., creating a gallery from images attached to the post or rendering a video.

Settings in

WordPress provides two core APIs to make the administrative interfaces easy to build, secure, and consistent with Administration’s design.

The Settings API focuses on giving way for developers to build forms and manage form data.

The Options API focuses on managing data using a simple key/value system.