@wpmark https://highrise.digital Easy Extensible Plugins Mark Wilkinson (@wpmark) WordPress Leeds July 2017 

@wpmark https://highrise.digital Mark Wilkinson Using & building WordPress sites for over 10 years as a WordPress developer Owner of Highrise Digital Follow me: @wpmark 

@wpmark https://highrise.digital What? Why? Tools / Functions 

@wpmark https://highrise.digital Plugin and or Theme 

@wpmark https://highrise.digital An Extensible Plugin 

@wpmark https://highrise.digital An Extensible Plugin is a plugin that can be modified or extended without changing the plugin code itself 

@wpmark https://highrise.digital Why? 

@wpmark https://highrise.digital Safe Functionality Modification 

@wpmark https://highrise.digital Safe Front-end Output Modification 

@wpmark https://highrise.digital https://www.flickr.com/photos/damndirty/10166197684 

@wpmark https://highrise.digital 

@wpmark https://highrise.digital How does core do extensibility? 

@wpmark https://highrise.digital Hooks Actions & Filters 

@wpmark https://highrise.digital Hooks Actions & Filters do_action() 

@wpmark https://highrise.digital Hooks Actions & Filters apply_filters() 

@wpmark https://highrise.digital 

@wpmark https://highrise.digital /wp-admin/edit-form-advanced.php apply_filters( 'enter_title_here', __( 'Enter title here' ), $post ); 

@wpmark https://highrise.digital function wpmark_title_here( $title, $post ) { if ( 'post' === get_post_type( $post ) ) { $title = 'Article Title'; } return $title; } add_action( 'enter_title_here', 'wpmark_title_here', 10, 2 ); apply_filters( 'enter_title_here', __( 'Enter title here' ), $post ); /wp-admin/edit-form-advanced.php 

@wpmark https://highrise.digital apply_filters( 'enter_title_here', __( 'Enter title here' ), $post ); /wp-admin/edit-form-advanced.php function wpmark_title_here( $title, $post ) { if ( 'post' === get_post_type( $post ) ) { $title = 'Article Title'; } return $title; } add_action( 'enter_title_here', 'wpmark_title_here', 10, 2 ); 

@wpmark https://highrise.digital Implementing this in our plugins 

@wpmark https://highrise.digital Implementing this in our plugins Setting up arrays Before / after HTML Output Function returns 

@wpmark https://highrise.digital Setting up arrays $job_posts = new WP_Query( array( ‘post_type’ => ‘wpmark_job’, ‘posts_per_page => 12 ) ); 

@wpmark https://highrise.digital Setting up arrays $job_posts = new WP_Query( apply_filters( ‘wpmark_job_post_query_args’, array( ‘post_type’ => ‘wpmark_job’, ‘posts_per_page => 12 ) ) ); 

@wpmark https://highrise.digital Before / after while ( $job_posts->have_posts() ) : $job_posts->the_post(); // do stuff with each post. endwhile; 

@wpmark https://highrise.digital Before / after while ( $job_posts->have_posts() ) : $job_posts->the_post(); do_action( ‘wpmark_before_job_post’, $post ); // do stuff with each post. do_action( ‘wpmark_after_job_post’, $post ); endwhile; 

@wpmark https://highrise.digital Even better? while ( $job_posts->have_posts() ) : $job_posts->the_post(); do_action( ‘wpmark_job_post’, $post ); endwhile; 

@wpmark https://highrise.digital Function returns function wpmark_sub_title( $post_id = 0 ) { return get_post_meta( $post_id, ‘subtitle’, true ); } 

@wpmark https://highrise.digital Function returns function wpmark_sub_title( $post_id = 0 ) { return apply_filters( ‘wpmark_sub_title’, get_post_meta( $post_id, ‘subtitle, true ), $post_id ); } 

@wpmark https://highrise.digital Other examples of extensibility Template overides Filterable views - outputting messages etc. Widget & shortcode templates Plugin adds functionality using hooks 

@wpmark https://highrise.digital Thank you for listening Any questions?