How To Write a WordPress Plugin

How To Write a WordPress Plugin

• 1.
  How to Writea WordPress Plugin Baltimore WordPress Meetup • September 19, 2011
• 2.
  What is aplugin? Written in PHP Adds functionality without affecting core code Plugin API
• 3.
  Hooks: Actions & Filters
• 4.
  Actions Hey, WP! I’dlike to do this when you do that... Calls a function that performs an action, possibly with some data given by WP
• 5.
  Actions add_action( $hook_name, $function); add_action(‘wp_head’, ‘my_custom_js’); add_action(‘wp_head’, array( $some_object, ‘my_custom_js_method’) ));
• 6.
  Actions init wp_head save_post
• 7.
  Filters Hey, WP! I’dlike to change a value that you’re returning/ using... Calls a function that returns a final
• 8.
  Filters add_filter( $hook_name, $function); add_filter(‘the_content’, ‘my_content_filter’); add_filter(‘the_content’, array( $some_object, ‘my_content_method) ));
• 9.
  Filters the_title the_content wp_email_from
• 10.
  Getting Started PHP fileor folder containing PHP file Javascript, CSS, etc. /wp-content/
• 11.
  Plugin Information <?php /* Plugin Name:My Simple Plugin Plugin URI: http://theandystratton.com/my-plugin Description: Does something awesome. Version: 1.0 Author: theandystratton Author URI: http://theandystratton.com License: GPL2 */
• 12.
  Info Shows inAdmin UI
• 13.
  Don’t Just Drop Code WordPress includes plugins while initializing Coding without hooking into actions/filters = explosion
• 14.
  Starting to Code Whatdo you want to do? I want to add my personal signature to all posts.
• 15.
  Starting to Code Whatdoes my plugin do? Filter the content of all posts and append my signature.
• 16.
  Some Code Hey WP! When you’re processing standard content, call this function!
• 17.
  Take the valueWP provides us, add my signature, give it back.
• 18.
  It’s as easyas that.
• 19.
  But we can complicatethings...
• 20.
  Archives, Listings, etc. Oops. I mean, I only want it to add my signature to the single post, not listings/ archives.
• 21.
  Archives, Listings, etc. What do you want to do now? Filter the content of all posts and append my signature
• 22.
  IF we’re ona single post page, THEN add my signature.
• 23.
  But we can complicatethings...
• 24.
  Post Type Content Oops.I have a custom post type called “Products,” and it’s adding my signature to those, too.
• 25.
  IF we’re ona single blog post page, THEN add my signature.
• 27.
  Getting More Advanced
• 28.
  Using Objects Avoid tons of prefixed functions Use a prefixed class to hold all your actions/filters
• 29.
  Using Objects
• 30.
  Do All Kindsof Fun Stuff
• 31.
  Plugins Do Way More Custom Post Types Shortcodes Metaboxes and metadata management
• 32.
  Plugins Do Way More Settings Pages Settings Fields Incorporate Internationalization
• 33.
  Plugins Do Way More Redirect requests Modify Rewrite Rules Emulate CRON jobs (wp- cron.php)
• 34.
  Going Public
• 35.
  Get in the Repository Submit your plugin code http://wordpress.org/extend/plugins/ about/ http://wordpress.org/extend/plugins/ about/faq/
• 36.
  Get in the Repository Readme.txt http://wordpress.org/extend/plugins/ about/readme.txt
• 37.
  Get in the Repository Subversion access & management Support URL? Update within 2 years or hide
• 38.
  More Resources “Writinga Plugin” http://codex.wordpress.org/ Writing_a_Plugin “WordPress Coding Standards” http://codex.wordpress.org/ WordPress_Coding_Standards
• 39.
  Google Works Great
• 40.
  Keep It SimpleStupid.
• 41.
  Code is poetry.
• 42.
  Thanks.