Bending WordPress to Your Will (October 2018)

These slides are slightly modified from a previous talk I gave with the same title.

WordPress is an incredibly powerful platform and framework for development, but until you learn how to use it you won't be able to make full use of its flexibility. In this session you will learn the core principles of WordPress development that will enable you to start taking full advantage of everything that it offers.

I gave this presentation at the Cape Town Develop UG on 29 October 2018: https://www.meetup.com/DeveloperUG/events/bcqgbqyxnbdc/

Transcript

1. Bending WordPress To Your Will
3. Folder Structure Headers Events Plugin Development
4. wp-content/plugins/plugin-slug > plugin-slug.php > readme.txt Folder Structure
5. Headers /* * Plugin Name: Seriously Simple Podcasting * Version: 1.9.6 * Plugin URI: https://wordpress.org/plugins/seriously-simple-podcasting/ * Description: Podcasting the way it's meant to be. * Author: Hugh Lashbrooke * Author URI: https://hugh.blog/ * Requires at least: 4.6 * Tested up to: 4.9.8 * * Text Domain: seriously-simple-podcasting */
6. PHP call_user_func() WordPress do_action() apply_filters() Events
7. do_action( ‘hook’ ); add_action( ‘hook’, ‘my_function’ ); Events: Hooks
8. <div id=”container”> <?php do_action( ‘div_content’ ); ?> </div> Events: Hooks - Example
9. add_action( ‘div_content’, ‘my_content’ ); function my_content() { echo “<span>Hello world!</span>”; } Events: Hooks - Example
10. <div id=”container”> <span>Hello world!</span> </div> Events: Hooks - Example
11. add_action( ‘hook’, ‘my_function’, 10 ); Lower number == higher priority Events: Priorities
12. add_action( ‘hook’, ‘my_function’, 10, 2 ); function my_function ( $foo, $bar ) { ... } Events: Parameters
13. apply_filters( ‘filter’, $foo ); add_filter( ‘filter’, ‘my_function’ ); Filters must always return a value Events: Filters
14. $v = apply_filters( 'body_class', $classes ); Events: Filters - Example
15. add_filter( ‘body_class’, ‘add_my_class’ ); function add_my_class( $classes ) { $classes[] = ‘my-class’; return $classes; } Events: Filters - Example
16. remove_action( ‘hook’, ‘function’ ); remove_filter( ‘filter’, ‘function’ ); Priorities must match original hook/filter Removing Hooks & Filters
17. <?php /* * Plugin Name: YouTube Redirect * Version: 1.0 */ add_action( ‘init’, ‘youtube_redirect’ ); function youtube_redirect () { if( isset( $_GET[‘youtube_redirect’] ) ) { wp_redirect( ‘https://youtube.com’, 302 ); exit; } } ?> Bringing it Together
18. Varying Vagrant Vagrants: varyingvagrantvagrants.org Plugin Developer Info: wordpress.org/plugins/developers Coding Standards: make.wordpress.org/core/handbook/best-practices/coding-standards Plugin Template: github.com/hlashbrooke/WordPress-Plugin-Template
19. hugh.blog @hlashbrooke automattic.com make.wordpress.org