This document discusses how to build your own WordPress plugin. It explains that plugins allow you to enhance WordPress functionality by adding extra features. It provides an overview of the necessary skills and files needed to build a plugin, including PHP knowledge, understanding WordPress structure, and having good ideas. It also covers best practices like giving the plugin a home directory and prefixing variables/functions. The document demonstrates how to register plugins with actions and filters to hook into WordPress and modify content.

1. Build your own Plugin

2. Build your own WordPress Plugin
Speaker
Alexandre Marreiros
Tech Trainner and Speaker and Consultnat as Independent
CTO Innovagency
Contacts
@alexmarreiros | amarreiros@gmail.com
digitalmindignition.com

3. Build your own WordPress Plugin
Plugin
“Plug-ins are a great way to enhance the
functionality of your blog or WebSite by adding
in extra features. These can be placed
anywhere inside your template by function
hooks. Over time the extensibility of WordPress’
plug-in system has allow tremendous growth
and hundreds of developer-submitted pieces of
software.”

4. Build your own WordPress Plugin
What i need to build plugin’s
Knowledge of PHP (Rudimentar)
Basic understanding of the WordPress file
structure
Good Ideias or problems

5. Build your own WordPress Plugin
Why Build Plugin’s
When you need to solve a recorrent
WordPress development need
When you need to extende the plataform
To a better understaning of the WordPress
Backend

6. Build your own WordPress Plugin
Where Plugin’s Live?

7. Build your own WordPress Plugin
Best Pratice 1
Give a “Home” to your Plugin this way you
simplify Plugin file system struture
Create a readme.txt file to explain who are
the person who knows how the Plugin is
built

8. Build your own WordPress Plugin
To Start
Create the base PHP file for your Plugin
You must start with the plugin declaration

9. Build your own WordPress Plugin
2 Build Aproaches
Create an entire class system to avoid
collisions with functions and variable names
that already exist.
just write your code in sample functions.

10. Build your own WordPress Plugin
Best Pratice 2
Don’t do Suicide if your plugin is simple
don’t start building a entire new class
ecosystem for him.

11. Build your own WordPress Plugin
Best Pratice 3
To avoid duplication use prefixing labels to
all your variables and function names.

12. Build your own WordPress Plugin
Actions and Filters
“Actions and Filters allow for plug-in
developers to update bits of code throughout
the WordPress admin panel pertaining to
your new plug-in. This means you could add
a new tab in the sidebar or additional
settings links for your Plug-in options.”

13. Build your own WordPress Plugin
Filter
A filter is used on data being passed into
WordPress. With filters you are quite literally
able to filter content through your own custom
written functions to change data in any way.
Used in cases like writing a sidebar widgets or
smaller functions to change how a post should
be displayed.

14. Build your own WordPress Plugin
Actions
Target pre-defined areas in your templates
and admin panel. Is important if your Plugin
intend to be triggered when something
happens in your WordPress event Pipeline.
publish_post – called when a post is published or when status is
changed into “published”
save_post – called when a post/page is created from start or updated
wp_head – called when the template is loaded and runs
the wp_head() function
loop_end – called immediately after the final post has been processed
through the WordPress loop
trackback_post – called whenever a new trackback is added into a post

15. Build your own WordPress Plugin
Plugin Registering
Plugin Creates Register
Plugin is
his Hooks in functions as a
installed
WP Action Listener
Plugin is Register
“hooked” to functions as a
WordPress Filter Listen

16. Build your own WordPress Plugin
When Plugin is Called
Wordpress Wordpress
executes an Validates all the
action or render s register functions
Call Plugins
functions
(considering
registering order)

17. Build your own WordPress Plugin
Best Pratice 4
Be carefull not to destruct what plugin’s that
came before you had made.

18. Build your own WordPress Plugin
Demo

19. Build your own WordPress Plugin
Questions
 Your turn to Talk
Resources
 http://codex.wordpress.org/Writing_a_Plugin
 Professional WordPress Plugin
Development by Brad Williams, Ozh Richard and
Justin Tadlock
 WordPress 3 Plugin Development Essentials by
B Bondari and E Griffiths (24 Mar 2011)