writing your first wordpress plugin

Writing Your First Plugin

by Mark Jaquith

@markjaquithmarkjaquith.com

Saturday, August 21, 2010

Assumptions

•You know PHP syntax

•You’re targeting PHP 5


What I want you to learn

•Plugins change what WordPress does

•They rely on the concepts of actions and filters

•There are numerous internal WordPress APIs for you to use


What is a Plugin?

•PHP code that sits in separate files

•Integrates tightly with WordPress

•Can add, alter, or remove functionality


Where?• wp-content/plugins/name.php

• wp-content/plugins/folder/name.php

• WordPress only looks one level deep

• It looks for .php files with a plugin header


Plugin Header

“Plugin Name” is required.


Basic Structure

•Build some stuff

•Tell WordPress to use that stuff when WordPress does certain stuff


Actions•Triggered when various things

happen in WordPress core

•“Wakes up” code you’ve registered against that action


Actions


Filters•WordPress passes data to your

code

•Your code optionally changes the data, then returns it to WordPress


Filters


How to organize your plugin


Prefix

cws_spn_function_name()


Singleton


Singleton variation


Most ImportantAction in WordPress

initSaturday, August 21, 2010

Let’s build a plugin!

• Insert mailing address and phone number into a post or a page

• Use a shortcode... [address]

• Configurable address and phone number

• Option to show phone number by default (or not)

• Ability to override the phone number default


Settings form handle

Setting name


Section handle

TitleContent callback



HTML id

Title

Content callback


Section handle


http://txfx.net/s/3q




writing your first wordpress plugin

Technology

plugin header plugin

wordpress core

filters wordpress

php code

phone number default

organizeyour plugin

phone number option

code youve