1. WordCamp NYC 2009 Writing Plugins for WordPress MU by Ron Rennick

2. Where to find me

http://wpmututorials.com

http://ronandandrea.com /contact/

http://freebpthemes.com

http://musupport.net

@wpmuguru

http://profiles.wordpress.org/wpmuguru

3. Overview

A little out of order -

Background

Traps

Tips

Tricks

Discussion

4. Background

Freelancing 16 years

Teaching

WordPress

5. Traps

Template tags

6. Traps

Template tags

$_SERVER['PHP_SELF']

7. Traps

Template tags

$_SERVER['PHP_SELF']

wp-content/uploads

8. Traps

Template tags

$_SERVER['PHP_SELF']

wp-content/uploads

plugin tables

9. Tips

Am I WordPress MU ?

• global $wpmu_version;

• if( isset( $wpmu_version ) ) {

• • // do MU specific code

• } else {

• • // do standard WP code

• }

10. Tips

Globals/Constants

$current_blog

$current_site

11. Tips

Globals/Constants

$current_blog

$current_site

VHOST

$bp

12. Tips

Functions

get_site_option($key, $default)

update_site_option($key, $value)

is_site_admin()

13. Tips

Functions

get_site_option($key, $default)

update_site_option($key, $value)

is_site_admin()

switch_to_blog($id)/restore_current_blog()

$wpdb->get_blog_prefix($id)

14. Tips

Constants

WPMU_PLUGIN_DIR

WPMU_PLUGIN_URL

BLOGUPLOADDIR

15. Tips

Global tables

$wpdb->site

$wpdb->blogs

$wpdb->sitemeta

$wpdb->sitecategories

16. Tricks

Filters

'pre_site_option_' . $key

'site_option_' . $key

'pre_update_site_option_' . $key

'pre_add_site_option_' . $key

17. Tricks

Hooks

muplugins_loaded

delete_blog

wpmu_new_user

wpmu_new_blog

18. Tricks

Functions

get_site_option($key, $default)

update_site_option($key, $value)

19. Tricks

Functions

get_site_option($key, $default)

update_site_option($key, $value)

Tables

make it global

add blog_id field to table

20. Remember Code is poetry