This document provides an overview of WordPress development, including: - The file structure and database schema of a WordPress site - How to add debugging tools and configure wp-config.php - The anatomy of WordPress themes like index.php, functions.php, and style.css - How to create plugins and customize WordPress through plugins, custom post types, taxonomies and more - Resources for WordPress core development like versioning, mailing lists and the Trac system

1. Intro To WordPress DevelopmentKenny Younger (@kenny)&Andy Brudtkuhl (@abrudtkuhl)

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

3. Database

4. Database SchemaSource: SchemaBank.com

5. File Structure

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

7. wp-config.phpdefine('WP_ALLOW_MULTISITE', true);

8. Debugging made easyDebugging 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/

9. WordPress ThemesWhat are themes? A way to skin WordPress

10. What’s In A WordPress Theme?WordPress themes are a combination of PHP, CSS, and image filesRequirements:HTMLCSSSome PHP

11. Anatomy Of A WordPress Theme

12. Theme StructureIndex.phpincludes header.phpIncludes sidebar.phpIncludes footer.php

13. Standard Theme ArchitectureHomepageindex.phphome.phpSingle Postsingle.phpPagepage.phpCategorycategory.phparchive.phpTags

14. tag.php

15. Search Results

16. search.php

17. 404

18. 404.php

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

20. Functions.phpContains theme related functions and commonly is used to generate dynamic sidebars

21. The LoopIf (havePosts) show post stuffElse nothing here!End if

22. Template Tagsthe_title()

23. the_permalink()

24. the_content()

25. the_excerpt()

26. And more!Theme Frameworks

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

28. The Plugin Directoryhttp://wordpress.org/extend/plugins/

29. The Plugin APIThe API provides “Hooks” into WordPressNo more hacking the coreMade up of Actions and FiltersActions = functions triggered by eventsie: Call function on user log inFilters = functions that modify informationie: Add facebook share button before post

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

31. Admin MenusCustom option panels for users to update settings for your pluginAdds options in WordPress Admin Dashboard

32. Users & Roles & CapabilitiesWordPress is designed to handle multiple users – from admin and editors to subscribers5 Pre-Defined RolesAdministratorEditorAuthorContributorSubscriberhttp://codex.wordpress.org/Roles_and_Capabilities

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

34. Custom Post TypesUsed for:Real Estate ListingEvent CalendarMovie DatabaseIssue Management / Ticket SystemEtc.