Slide 1
Slide 1 text
How to write extensible
WordPress code
Mark Wilkinson
Co-founder and developer at Highrise Digital
https://highrise.digital
@wpmark
Slide 2
Slide 2 text
What is extensible
WordPress code?
Slide 3
Slide 3 text
“
capable of being extended
- dictionary.com
Slide 4
Slide 4 text
“
Code which can be modified or
extended, without changing the
code itself.
- Mark Wilkinson
Slide 5
Slide 5 text
Why write extensibly?
Slide 6
Slide 6 text
So, how do I write
extensible WordPress
code?
Slide 7
Slide 7 text
Use the force core
Slide 8
Slide 8 text
Use the force core
How does WordPress core do
extensibility?
Slide 9
Slide 9 text
Hooks
Slide 10
Slide 10 text
Hooks
Actions & Filters
Slide 11
Slide 11 text
https://highrise.digital/blog/wordpress-hooks-action-filters
/
Slide 12
Slide 12 text
Actions
do_action()
Slide 13
Slide 13 text
do_action(
‘my_action_name’
);
Slide 14
Slide 14 text
Filters
apply_filters()
Slide 15
Slide 15 text
apply_filters(
‘my_filter_name’,
$filterable_thing
);
Slide 16
Slide 16 text
No content
Slide 17
Slide 17 text
apply_filters(
'enter_title_here',
__( 'Enter title here' ),
$post
);
Slide 18
Slide 18 text
function hd_title_here( $title, $post ) {
if ( 'post' === get_post_type( $post ) ) {
$title = 'Article Title';
}
return $title;
}
add_filter( 'enter_title_here', 'hd_title_here', 10, 2 );
Slide 19
Slide 19 text
Implementing this in your
own code
Slide 20
Slide 20 text
Arrays of data
HTML Output
Function returns
Slide 21
Slide 21 text
Arrays of data
HTML Output
Function returns
Slide 22
Slide 22 text
$job_posts = new WP_Query(
array(
‘posts_per_page => 6,
‘post_type => ‘hd_job’,
)
);
Slide 23
Slide 23 text
$job_posts = new WP_Query(
apply_filters(
‘hd_job_post_query_args’,
array(
‘posts_per_page => 6,
‘post_type => ‘hd_job’,
)
)
);
Slide 24
Slide 24 text
Arrays of data
HTML Output
Function returns
Slide 25
Slide 25 text
while ( $job_posts->have_posts() ) :
$job_posts->the_post();
?>
Slide 26
Slide 26 text
while ( $job_posts->have_posts() ) :
$job_posts->the_post();
do_action( ‘hd_before_job_post’ );
?>
Slide 27
Slide 27 text
while ( $job_posts->have_posts() ) :
$job_posts->the_post();
do_action( ‘hd_job_post’, $post );
endwhile;
Slide 28
Slide 28 text
function hd_job_post_content( $post ) {
?>
Slide 29
Slide 29 text
remove_action(
‘hd_job_post’,
‘hd_job_post_content’,
10,
1
);
Slide 30
Slide 30 text
Arrays of data
HTML Output
Function returns
Slide 31
Slide 31 text
function hd_sub_title( $post_id = 0 ) {
return get_post_meta(
$post_id,
‘subtitle’,
true
);
}
Slide 32
Slide 32 text
function hd_sub_title( $post_id = 0 ) {
return apply_filters(
‘hd_sub_title’,
get_post_meta(
$post_id,
‘subtitle’,
true
),
$post_id
);
}
Slide 33
Slide 33 text
Template overrides
Slide 34
Slide 34 text
Template overrides
https://github.com/GaryJones/Gamajo-Template-Loader
Slide 35
Slide 35 text
Pluggable Functions
Slide 36
Slide 36 text
if ( ! function_exists( ‘hd_function’ ) ) {
function hd_function() {
// awesome functions stuff here!
}
}
Slide 37
Slide 37 text
Mark Wilkinson
Co-founder & developer at Highrise
Digital
T: @wpmark & @highrisedigital
W: markwilkinson.me & highrise.digital