An introduction to writing your first WordPress plugin. These are simple slides that accompanied an in-depth presentation.

1. Writing Your Own Plugins
The basics and more
Pippin Williamson
pippinsplugins.com
@pippinsplugins

2. What makes up a plugin?
wp-content/plugins/my-plugin-name/
.php files
.js files
.css files
.mo/po files
image files

3. What defines a plugin?

4. The plugin header
wp-content/plugins/my-plugin/my-plugin.php
<?php
/**
* Plugin Name: My Plugin Name
* Description: A simple plugin
* Version: 1.0
* Author: Pippin Williamson
* Author URI: http://pippinsplugins.com
*/

5. The plugin header
plugins/simple-post-expiration/simple-post-expiration.php
<?php
/**
* Plugin Name: Simple Post Expiration
* Description: A simple post expiration plugin
* Version: 1.0
* Author: Pippin Williamson
* Author URI: http://pippinsplugins.com
*/

6. /wp-admin/plugins.php

7. Quick demo time

8. The plugin API
Action hooks:
do_action()
add_action()
remove_action()
remove_all_actions()
has_action()
did_action()
doing_action

9. Quick demo time
wp_footer action
https://github.com/WordPress/WordPress/blob/master/w
p-includes/general-template.php#L2051

10. The plugin API
Filter hooks:
apply_filters()
add_filter()
remove_filter()
remove_all_filters()
has_filter()
current_filter()
doing_filter()

11. Quick demo time
the_title filter
https://github.com/WordPress/WordPress/blob/master/w
p-includes/post-template.php#L99

12. Plugins for Inspiration
There are so many possibilities

13. Inspiring Dashboard
Not sure what to write about for your next blog post?
Maybe this Dashboard Widget can inspire you.
Adds a dashboard widget
Provides quick inspiration on something to write
http://wordpress.org/plugins/inspiring-dashboards/

14. Multi Site Plugins Add New
Enables the “Add New” menu under Plugins for multisite
The Add New Plugin screen is hard to get to
This plugin adds a shortcut
http://wordpress.org/plugins/multi-site-plugins-add-new/

15. CodePen oEmbed
Adds oEmbed support for CodePen.io
The Add New Plugin screen is hard to get to
This plugin adds a shortcut
http://wordpress.org/plugins/codepen-oembed/

16. Remove Comment Notes
Removes the notes section below the comment form
The notes section can create clutter
It isn’t needed in the majority of cases
http://wordpress.org/plugins/remove-comment-notes/

17. Write First
Blogging is about writing
Sends users directly to the edit screen upon login
http://wordpress.org/plugins/write-first/

18. Simple Post Expiration
A simple plugin to add an expiration date to posts
adds an “Expires on” field to post editor
prepends “Expired” to post titles once expired
is really simple
https://github.com/pippinsplugins/simple-post-expiration

19. Items to keep in mind

20. Overall structure of the plugin

21. How the data is stored

22. Features for launch

23. Features for tomorrow

24. Updates

25. Backwards compatibility

26. How the plugin will be distributed

27. When will you get started?