This document discusses mu-plugins in WordPress. Mu-plugins require manual installation, activate automatically, are persistent, and do not work in subdirectories like regular plugins. The document provides an example of using a mu-plugin to add CSS to a theme in a future-proof way. It notes that mu-plugins grant abilities beyond regular plugins, themes, and dropins due to their persistence, and are useful for library code and APIs.

1. Unlock the power of
WordPress
Using mu-plugins
By Mikel King

2. Mu-plugins
● Require manual installation
● Activate automatically
● Are persistent
● Do not work in subdirectories like regular plugins*
● Should not alter the DB schema**

3. Mu-plugins
● Require manual installation
● Activate automatically
● Are persistent
● Do not work in subdirectories like regular plugins*
● Generally should not alter the DB schema**
* There are methods and mu-plugin managers to help use regular plugins as mu’s

4. Mu-plugins
● Require manual installation
● Activate automatically
● Are persistent
● Do not work in subdirectories like regular plugins*
● Generally should not alter the DB schema**
* There are methods and mu-plugin managers to help use regular plugins as mu’s
** This is a use at your own risk kind of situation

5. Goals...
● Familiarize you with mu-plugins
● Expose you to a new tool
● Expand your horizons

6. Why use mu-plugins?

7. Why use mu-plugins?
● They grant you abilities that other systems of
modification do not (dropins, themes, plugins)

8. ● They grant you abilities that other do not
(dropins, themes, plugins)
● The persistence model can be used to your
advantage (library code, api’s etc...)
Why use mu-plugins?

9. Let’s look at an example

10. Theme augmentation
News Magazine Theme

11. Theme augmentation
News Magazine Theme

12. Side by side comparison

13. Let’s look at some code!!!
https://github.com/mikelking/singleton_base
000-singleton-base.php
010-base-plugin.php

14. tabular-css/plugin.php
Tabular-css tree

15. tabular-data.css

16. Let’s take a deeper look at some code!!!
https://github.com/mikelking/singleton_base
000-singleton-base.php
010-base-plugin.php

17. So what’s the point?
● Can’t I just add the css to the main style sheet?

18. So what’s the point?
● Can’t I just add the css to the main style sheet?
● Or put it in it’s own file and @import it?

19. So what’s the point?
● Can’t I just add the css to the main style sheet?
● Or put it in it’s own file and @import it?
● Or enqueue it through function.php?

20. So what’s the point?
● Can’t I just add the css to the main style sheet?
● Or put it in it’s own file and @import it?
● Or enqueue it through function.php?
● Really I’m having trouble connecting the dots, man.

21. Well the point is that:
None of those methods are future proof.
You are responsible for reimplemention after EVERY
update.
None of those methods are easy to troubleshoot.
A plugin built like this can be turned off
Hey man this is just a high level example.
Actually this is a real world example.

22. Unlock the power of
WordPress
Using mu-plugins
By Mikel King
This has been:

23. Contact info:
https://twitter.com/mikelking
https://www.linkedin.com/in/mikelking
https://github.com/mikelking