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
   

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3. Folder Structure
   Headers
   Events
   Plugin Development
   

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4. wp-content/plugins/plugin-slug
   > plugin-slug.php
   > readme.txt
   Folder Structure
   

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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
   */
   

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6. PHP
   call_user_func()
   WordPress
   do_action()
   apply_filters()
   Events
   

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7. do_action( ‘hook’ );
   add_action( ‘hook’, ‘my_function’ );
   Events: Hooks
   

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8. 
   do_action( ‘div_content’ );
   ?>
   
   Events: Hooks - Example
   

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9. add_action( ‘div_content’, ‘my_content’ );
   function my_content() {
   echo “Hello world!”;
   }
   Events: Hooks - Example
   

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10. 
    Hello world!
    
    Events: Hooks - Example
    

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11. add_action( ‘hook’, ‘my_function’, 10 );
    Lower number == higher priority
    Events: Priorities
    

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12. add_action( ‘hook’, ‘my_function’, 10, 2 );
    function my_function ( $foo, $bar ) {
    ...
    }
    Events: Parameters
    

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13. apply_filters( ‘filter’, $foo );
    add_filter( ‘filter’, ‘my_function’ );
    Filters must always return a value
    Events: Filters
    

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14. $v = apply_filters( 'body_class', $classes );
    Events: Filters - Example
    

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15. add_filter( ‘body_class’, ‘add_my_class’ );
    function add_my_class( $classes ) {
    $classes[] = ‘my-class’;
    return $classes;
    }
    Events: Filters - Example
    

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16. remove_action( ‘hook’, ‘function’ );
    remove_filter( ‘filter’, ‘function’ );
    Priorities must match original hook/filter
    Removing Hooks & Filters
    

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17. /*
    * 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
    

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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
    

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19. hugh.blog
    @hlashbrooke
    automattic.com
    make.wordpress.org
    

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