When developing plugins or themes there are certain considerations one needs to make if you want to make sure your plugin or theme supports multsite. In this session, we'll cover those considerations, look at some specific multisite APIs, and convert an existing plugin to support multsite.

1. Jonathan Bossenger
Learn.WordPress.org
Developing for multisite

2. 2
👋🏽
Welcome!
As you join, please make sure you have your local
development environment ready:
• A local WordPress multisite installation
• A code editor like VSCode or Sublime
• https://github.com/jonathanbossenger/wp-
learn-plugin-
security/releases/download/1.0.3/wp-learn-
plugin-security.1.0.3.zip
• https://github.com/jonathanbossenger/twentyt
wentythreechild/releases/download/1.0.0/twen
tytwentythreechild.zip
Then, let everyone know in the chat where you’re
Hello!
○ My name is Jonathan Bossenger
○ From Cape Town, South Africa
○ Developer educator at Automattic
○ Sponsored to work with the Training Team
○ jonathanbossenger.com

3. Learn.WordPress.org
Developing for multisite
Jonathan Bossenger

4. Announcements
○ Welcome, and thank you to Thelma for co-hosting.
○ Please let me know if you can’t see this slide!
○ We are presenting in focus mode, but please feel free to enable your video.
○ You are welcome to ask questions.
○ You are welcome to post questions in the chat, or unmute to ask questions.

5. Announcements
○ Make sure your local multisite install is ready
• https://github.com/jonathanbossenger/twentytwentythreechild/releases/downl
oad/1.0.0/twentytwentythreechild.zip
• https://github.com/jonathanbossenger/wp-learn-plugin-
security/releases/download/1.0.3/wp-learn-plugin-security.1.0.3.zip
○ If I am going too fast, please let me know!
○ We will be posting this session to https://wordpress.tv/ afterwards
○ For more WordPress focused content please visit https://learn.wordpress.org/

6. Learning Outcomes
1. Developing for multisite: useful resources
2. Developing themes or child themes for a multisite network
3. Developing plugins for a multisite network

7. On developing for multisite support
○ Much of multisite development theory is largely undocumented
○ There is no “multisite specific” section in the plugin or theme developer handbooks
○ It is useful to work through the wp-admin/network directory for all multisite admin specific
functionality
○ Test, test, test on a multisite network

8. Useful multisite related functions
○ is_multisite
○ Is_main_site
○ is_super_admin
○ is_network_admin
○ network_admin_url
○ get_blogs_of_user
○ is_network_only_plugin

9. Useful multisite related functions
○ get_sites
○ switch_to_blog
○ restore_current_blog
○ update_blog_option
○ get_current_blog_id

10. Useful multisite related hooks
○ network_admin_menu
○ network_admin_notices
○ signup_blogform
○ wp_initialize_site
○ wpmu_blogs_columns
○ manage_sites_custom_column

11. 11
Let’s code.