Module 8: Plugin Development

OOP in WordPress

Write plugins using modern PHP standards (PSR-4).

Key Concepts

• Boilerplate: Starting with a solid foundation.
• Hooks: Actions and Filters deep dive.
• Settings API: Creating admin pages correctly.

1. PSR-4 Autoloading

Use Composer to autoload your plugin classes. No more `require_once`.

"autoload": {
    "psr-4": {
        "MyPlugin\\": "src/"
    }
}

2. The Singleton Pattern

Ensure your main plugin class is only instantiated once.

3. Activation & Deactivation Hooks

Create tables or schedule cron jobs when the plugin is activated. Clean up on deactivation.

4. Custom Post Types (CPT)

Register CPTs for structured content. Use a class-based approach.

5. Shortcodes vs Blocks

Shortcodes are legacy. Build Blocks for the editor, but know how to support shortcodes for backward compatibility.

6. The Settings API

Don't build custom forms. Use the Settings API to register fields and sections in the admin area.

7. Transients & Caching

Cache expensive operations within your plugin using the Transients API.

8. Internationalization (i18n)

Make your plugin translatable. Wrap strings in `__('Text', 'domain')`.

9. Unit Testing

Use PHPUnit and `wp-browser` to test your plugin logic.

10. Publishing to Packagist

Host your private plugins on a private Packagist or Git repo to install them via Composer.