Wordcamp Toronto 2013 #WCTO2013

1. Writing Extensible
Plugins in
WordPress
#WCTO2013

2. Imran Nathani
 What I do?:
Team lead at Shaw Media for GlobalNews.ca
About Me
 Past Experience:
For 6 yrs I have been developing print and
broadcast news websites.
Of which 4 years, I have spent exclusively
developing on WordPress VIP.

3. Usability
Extensibility
is not
Usability
Extensibility
 Target audience :
All WordPress users
 Target audience:
Developers
 Expectations:
Options Page,
Shortcodes,
Widgets etc.
 Expectations:
?????

4. What is an
extensible
plugin?
A plugin that can be
modified and extended
beyond its original purpose
by another plugin or
theme without modifying
original plugin.

5. Why write
an
extensible
plugin?
 Saves time
 Increases code portability
 Makes extra money $-)
 Reduces documentation

6. Helper
functions
 “Helps” re-use code
 “Helps” make code easier to read

7. Hooks

8. Traditional function call
What are
hooks ?

9. Wordpress Hook call
What are
hooks ?

10. Wordpress hook call ( Multiple )
What are
hooks ?

11. What are
hooks ?
Hooks are placeholders
for code.

12. Action hook
Filter hook
 Extending methods
 Extend values
 Returns nothing
 Returns a value
do_action( … )
apply_filters( … )
Types of
hooks

13. Action
hook
Wherever an action hook
is placed, it will execute
any code that has been
“hooked” to it.

14. Usage A :
do_action( ‘hook-name’ );
Action
hook
usage
Usage B:
do_action( ‘hook-name’ , $arg1, $arg2, … );
Usage C:
do_action_ref_array( ‘hook-name’ , $array );

15. Utility functions
 add_action(..)
Actions
 remove_action(..)
 remove_all_actions(..)
 has_action(..)
 did_action(..)

16. Action placements
Actions
 Before a task
 After a task
 Append mark up

17. Core actions
 publish_post
Actions
 save_post
 wp_head
 wp_foot

18. Actions
DEMO

19. Filter
hooks
Wherever a filter hook is
placed, it will manipulate
any value that has been
passed into with the
function “hooked” to it

20. Usage A :
Filter
hook
usage
$value = apply_filters( ‘hook-name’ , $value )
Usage B :
$value = apply_filters( ‘hook-name’ , $value, $args, .. )

21. Utility functions
 add_filter(…)
Filters
 remove_filter(…)
 remove_all_filters(...)
 has_filter(…)
 current_filter( … )

22. Filter placements
Filters
 Before using values
 Before value set up
 Before returning values

23. Core filters
Filters
 the_title
 the_excerpt
 post_link
 the_date

24. Filters
DEMO

25. Improve efficiency
Tips
&
Tricks

26. Improve efficiency
Tips
&
Tricks

27. Prefix hook names
Tips
&
Tricks

28. Do not over extend!
Tips
&
Tricks

29. Validate returns
Tips
&
Tricks

30. Combine Filters
Tips
&
Tricks

31. Combine Filters
Tips
&
Tricks

32. Localize scripts with Filters
Tips
&
Tricks

33. Localize scripts with Filters
Tips
&
Tricks

34. Good
reads
Wordpress Codex ( How to? )
Wordpress Core ( Why to? )

35. Questions?