This document summarizes Barry Kooij's presentation on plugin development. It discusses Barry's setup for plugin development using a MacBook Air, PhpStorm IDE, and Git version control. It also covers debugging, code templates, leveraging WordPress core APIs and hooks, database usage, unit testing, documentation, object-oriented patterns, internationalization, and taking questions.

1. PLUGIN DEVELOPMENT
#wpmeetup010

2. BARRY KOOIJ
Twitter : @cageNL
Lead Developer WordPress @ INDICIA
Freelance @ Cageworks
Plugin developer
What The File
Sub Posts
Contributor EDD & extensies
Core contributor
Moderator WPNL forum

3. PLUGIN DEVELOPMENT

4. MIJN SETUP
Device
IDE
Versiebeheer
MacBook Air
PhpStorm
GIT, GitHub / private server
Commandline

5. ALTERNATIEVEN
IDE
GIT
SVN
NuSphere PhpED
Bitbucket, GitLab
Tower
Versions / Tortoise

6. DEBUGGIN
G
define( 'WP_DEBUG', true );
if ( WP_DEBUG ) {
define( 'SCRIPT_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', true );
@ini_set( 'display_errors', 0 );
}
display_errors = On;
error_reporting = E_ALL | E_STRICT;

7. CODE TEMPLATES
https://gist.github.com/barrykooij/7632945

8. WORDPRESS CORE
Open source, maak hier gebruik van!
API’s, API’S, API’s
Filters & Hooks

9. API’S
Dashboard Widgets API
Database API
HTTP API
File Header API
Filesystem API
Metadata API
Options API
Plugin API
Quicktags API
Rewrite API
Settings API
Shortcode API
Theme Modification API
Theme Customization API
Transients API
Widgets API
XML-RPC WordPress API

10. FILTERS & HOOKS
add_action( ‘hook_name’, ‘my_function’ );
do_action( ‘hook_name’ );

11. JS “HOOKS” (EVENTS)
$('body').bind(’event’, function(event,
the_value) {
});
$('body').trigger(’event', [ value ]);

12. BACKWARDS COMPATABILITY
Deprecate code
Pas later geen unit tests aan, maar voeg unit
tests toe

13. CODE STANDARDS
http://codex.wordpress.org/WordPress_Coding_Standards

14. NAMING CONVENTIONS
function some_name( $some_variable ) { [...] }
class Walker_Category extends Walker { [...] }
class WP_HTTP { [...] }
my-plugin-name.php
class-my-class.php

15. DATABASES
Gebruik altijd de API!
$wpdb->prepare
$wpdb->prepare( "SELECT * FROM {$wpdb>posts}" WHERE `ID` = %d", $special_id );

16. YODA CONDITIONS
if ( true == $the_force ) {
$victorious = you_will( $be );
}
A little bizarre, it is, to read. Get used to it, you will.

17. UNIT TESTING
PHPUnit
/**
* @ticket 22212
*/
function test_get_multiple_roles_by_user_query() {
$this->factory->user->create_many( 2, array( 'role' => 'subscriber’ ) );
$this->factory->user->create_many( 3, array( 'role' => 'editor’ ) );
$wp_user_search = new WP_User_Query( array( 'role' => array( 'subscriber’,
'editor' ) ) );
$users = $wp_user_search->get_results();
$this->assertEquals( 5, count( $users ) );
}

18. CHANGELOG
Hou bij wat je wanneer veranderd hebt

19. SUPPORT
Als je iets bouwt, support het dan
Geef op je website je support tijden aan
Support systemen

20. WORDPRESS.ORG REPO
Header afbeelding
Duidelijk omschrijving
Downloads i.c.m. rating
Vraag om ratings!

22. CONDITIONAL LOADING OF CODE
Laad code enkel waar nodig
is_admin()

23. DOCUMENTATION
Schrijf je code doc direct
Betere IDE suggesties

24. CODE

25. OBJECTGEORIËNTEERD
OOP
Singleton pattern

26. class My_Plugin {
private static $instance = null;
public static function get() {
if( null == self::$instance ) {
self::$instance = new self();
}
return self::$instance;
}
private function __construct() {
}
}

27. function My_Plugin() {
return My_Plugin::get();
}
add_action( 'plugins_loaded', function() {My_Plugin::get(); });

28. PLUGIN DIR & FILE
if ( ! defined( ’X_PLUGIN_DIR' ) ) {
define( 'X_PLUGIN_DIR’, plugin_dir_path( __FILE__ ) );
}
if ( ! defined( ’X_PLUGIN_FILE' ) ) {
define( ’X_PLUGIN_FILE', __FILE__ );
}

29. PREFIXES
WordPress : PHP version 5.2.4 or greater
Namespaces : 5.3.0 or greater
Tot die tijd, prefixen.
class SP_Post_Link_Manager { [...] }

30. SANITIZE & ESCAPE
sanitize_title
is_email
http://codex.wordpress.org/Data_Validation#In
put_Validation
esc_url
esc_html

31. CAPABILITIES
if ( ! current_user_can( SP_Cap_Manager::get_capability(
$_GET['sp_post_link'] ) ) ) {
return;
}

32. NONCES
Number used ONCE
wp_nonce_field( plugin_basename( __FILE__ ),
'sp_sortable_nonce' );
if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce(
$_POST['nonce'], plugin_basename( __FILE__ ) ) ) {
return;
}

33. DIRECT ACCESS
if ( ! defined( 'ABSPATH' ) ) exit; // Exit if
accessed directly

34. I18N
load_plugin_textdomain( 'sub-posts', false,
dirname( plugin_basename( __FILE__ ) ) .
'/languages/' );
_e( ‘my-string’, ‘sub-posts’ );

35. Q&
A
Twitter @cageNL
WordPress & Github: barrykooij
7 januari meetup in Tilburg