Getting Started With WordPress Development

Intro To WordPress Development
Kenny Younger (@kenny)
&
Andy Brudtkuhl (@abrudtkuhl)

What does WordPress look like to the users?
Let’s take a look!

Database

Database Schema
Source: SchemaBank.com

File Structure

/
wp-admin/
wp-content/
plugins/
Each plugin usually has its own directory
themes/
Each theme has its own directory
uploads/
Created on first upload (default location)
wp-includes/
wp-config.php

wp-config.php
define('WP_ALLOW_MULTISITE', true);

Debugging made easy
Debugging flags added to wp-config.php:
define( 'WP_DEBUG', true );
define( 'SCRIPT_DEBUG', true );
define( 'SAVEQUERIES', true );
$wpdb->queries
“All” hook:
add_action( 'all', create_function( '', 'var_dump( current_filter() );' ) );
Core Control Plugin:
http://wordpress.org/extend/plugins/core-control/
Dump Environment Plugin:
http://wordpress.org/extend/plugins/dump_env/
Source: http://www.andrewnacin.com/2010/04/23/5-ways-to-debug-wordpress/

WordPress Themes
What are themes? A way to skin WordPress

What’s In A WordPress Theme?
WordPress themes are a combination of PHP, CSS, and image files
Requirements:
HTML
CSS
Some PHP

Anatomy Of A WordPress Theme

Theme Structure
Index.php
includes header.php
Includes sidebar.php
Includes footer.php

Standard Theme Architecture
Homepage
index.php
home.php
Single Post
single.php
Page
page.php
Category
category.php
archive.php
Tags
tag.php
Search Results
search.php
404
404.php

The Stylesheet – style.css
The comment headers in the style.css provide meta info to WP are are REQUIRED
Thisstylesheet also controls the layout and design elements of your theme…

Functions.php
Contains theme related functions and commonly is used to generate dynamic sidebars

The Loop
If (havePosts)
show post stuff
Else
nothing here!
End if

Template Tags
the_title()
the_permalink()
the_content()
the_excerpt()
And more!

Theme Frameworks

What Is A WordPress Plugin?
Plugins are used to add or enhance functionalities of your WordPress site

The Plugin Directory
http://wordpress.org/extend/plugins/

The Plugin API
The API provides “Hooks” into WordPress
No more hacking the core
Made up of Actions and Filters
Actions = functions triggered by events
ie: Call function on user log in
Filters = functions that modify information
ie: Add facebook share button before post

Plugin Data
Sometimes it’s necessary to store data…
For large amounts, create a new database table
For small amounts, use WordPress “Options” – a table with key/value pairs

Admin Menus
Custom option panels for users to update settings for your plugin
Adds options in WordPress Admin Dashboard

Users & Roles & Capabilities
WordPress is designed to handle multiple users – from admin and editors to subscribers
5 Pre-Defined Roles
Administrator
Editor
Author
Contributor
Subscriber
http://codex.wordpress.org/Roles_and_Capabilities

Custom Fields
Allow attaching meta-data to posts.
http://www.smashingmagazine.com/2010/04/29/extend-wordpress-with-custom-fields/

Custom Post Types
Used for:
Real Estate Listing
Event Calendar
Movie Database
Issue Management / Ticket System
Etc.

Custom Post Type Options
label
singular_label
description
public – query-able from public?
menu_position
menu_icon
hierarchical
query_var
capability_type – permissions
supports
rewrite
taxonomies
register_meta_box_cb
permalink_epmask

Custom Post Types – Integration with the loop
<?php $loop = new WP_Query( array( 'post_type' => my_custom_post_type', 'posts_per_page' => 10 ) ); ?>
<?php while ( $loop->have_posts() ) : $loop->the_post(); ?>
<?phpthe_title( '<h2 class="entry-title"><a href="' . get_permalink() . '" title="' . the_title_attribute( 'echo=0' ) . '" rel="bookmark">', '</a></h2>' );
?>
<div class="entry-content">
<?phpthe_content(); ?>
</div>
<?phpendwhile; ?>

Taxonomies
What are taxonomies?
register_taxonomy()
Shows up in menu system
Demo
register_taxonomy(
'actor',
'post',
array(
'hierarchical' => false,
'label' => __('Actors', 'series'),
'query_var' => 'actor',
'rewrite' => array( 'slug' => 'actors' )
)
);

Core Development
Versioning
0.1 increments
Based on time, not features
Generally every 5-6 months
0.0.1 – usually security fixes, other small bug fixes
Always update!!
Mailing lists:
http://codex.wordpress.org/Mailing_Lists
Trac:
http://core.trac.wordpress.org

Resources
Planet - planet.wordpress.org
WordPress Codex – codex.wordpress.org
WordPress Forums – wordpress.org/support
All Things WordPress- wordpress.alltop.com
Core Development Blog – devel.wordpress.org

August 7th, Downtown Des Moines Public Library

Thanks!!!
Kenny Younger (@kenny)
&
Andy Brudtkuhl (@abrudtkuhl)

http://48web.com	24
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Getting Started With WordPress Development

by Andy Brudtkuhl

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