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![Custom WP Requests function wcpdx_parse_request($wp) { // only process requests with "wcpdx=ajax-handler" if (array_key_exists('wcpdx', $wp->query_vars) && $wp->query_vars['wcpdx'] == 'ajax-handler') { // process the request. } } add_action('parse_request', 'wcpdx_parse_request'); function wcpdx_query_vars($vars) { $vars[] = 'wcpdx'; return $vars; } add_filter('query_vars', 'wcpdx_query_vars');](https://image.slidesharecdn.com/wordcamppdx-090920163905-phpapp01/75/How-Not-to-Build-a-WordPress-Plugin-32-2048.jpg)
Uploaded byWill Norris
How Not to Build a WordPress Plugin
The document provides best practices for building WordPress plugins, including using unique function names prefixed with the plugin name, always using plugins_url() to reference plugin files, enqueueing styles and scripts properly, adding custom hooks for other plugins/themes to interact with, and handling AJAX requests through WordPress instead of direct file calls. It emphasizes designing plugins for flexibility and extensibility.
How Not to Build a WordPress Plugin
- 1. How Not toBuild a WordPress Plugin Will Norris < http://willnorris.com />
- 2. Upgradability Performance SecurityExtensibility
- 3.
- 4. Function Name Prefixwcpdx_activate() wcpdx_deactivate() wcpdx_uninstall()
- 5. Class class WordCampPDX{ function activate() function deactivate() function uninstall() }
- 6. Never Assume FileLocation
- 7. Traditional Directory Layoutexample.com/ wordpress/ wp-config.php wp-content/ plugins/ themes/
- 8. Non-Traditional Layout (sinceWP 2.6) example.com/ wordpress/ wp-config.php wordpress-content/ plugins/ themes/
- 9. Plugin URL urdoin it wrong: <img src=”<?php bloginfo(‘wpurl’) ?>/wp-content/plugins/wcpdx/logo.png” ?> dats bedder: <img src=”<?php echo WP_PLUGIN_URL ?>/wcpdx/logo.png ?>”/> you haz it: <img src=”<?php echo plugins_url(‘logo.png’, __FILE__) ?>” />
- 10. Plugin URL plugins_url()supports WPMU plugin directory auto detects SSL supports renamed plugin directory calls ‘plugins_url’ filter
- 11. Friends of plugins_url()site_url() admin_url() includes_url() content_url() no home_url() (why not?)
- 12. Including Files urdoin it wrong: include ‘../../wp-content/...’ dats bedder: include ABSPATH . ‘wp-content/...’ you haz it: include WP_CONTENT_DIR . ‘/...’
- 13. Find the RightHook Load as late as possible, but no later
- 14. Admin Hooks urdoin it wrong: add_action(‘admin_init’, ‘wcpdx_admin_init’) add_action(‘admin_head’, ‘wcpdx_admin_head’) you haz it: $hookname = add_options_page( ... ) add_action(“admin_load-$hookname”, ‘wcpdx_admin_init’) add_action(“admin_head-$hookname”, ‘wcpdx_admin_head’)
- 15. Styles and Scriptsur doin it wrong: <script rel=”<?php echo plugins_url(‘wcpdx.js’, __FILE__) ?>”></script> you haz it: wp_enqueue_script(‘wcpdx’, plugins_url(‘wcpdx.js’, __FILE__)) wp_enqueue_style(‘wcpdx’, plugins_url(‘wcpdx.css’, __FILE__))
- 16. Styles and Scriptswp_register_* and wp_enqueue_* support dependencies push scripts to footer caching support based on version (one day) server side concatenation
- 17. Add your ownhooks A strategically placed hook covers a multitude of sins.
- 18. Custom Hooks Cando everything core WP hooks do: event notification (actions) massage data (the_content) replace values (stylesheet) extend functionality (http_api_curl) replace functionality
- 19. Custom Hooks do_action(‘my-action’)do_action(‘my-action’, $a, $b) do_action_ref_array(‘my-action’, array($wcpdx)) apply_filters(‘my-filter’, $wcpdx) apply_filters(‘my-filter’, $wcpdx, $a, $b)
- 20.
- 21. Designed for FlexibilityWordPress database supports custom options arbitrary metadata for posts, users, and comments (2.9) custom taxonomies custom post types
- 22. Custom Post TypesUsed by WordPress core for posts pages revisions attachments
- 23. If it walkslike a duck... author date and time title content comments categories and tags permalink order hierarchy (additional arbitrary metadata)
- 24.
- 25. Admin Settings PagesDon’t waste time processing manually register_setting( ‘wcpdx’, ‘my-option’ ) http://codex.wordpress.org/Settings_API http://codex.wordpress.org/Creating_Options_Pages# Register_Settings
- 26. Admin Settings PagesDo you really need a dedicated page? Add options to any built-in settings page add_settings_field( ... )
- 27.
- 28. Direct Plugin FileCalls Direct HTTP request to plugin file ajax.php: echo ‘<script type=”text/javascript”> jQuery.get(“‘ . plugins_url(‘ajax.php’, __FILE__) . ‘”); // do something with AJAX data </script>’;
- 29. Direct Plugin FileCalls If ajax.php includes anything similar to: require_once(‘../../../wp-load.php’); ur doin it wrong
- 30. WordPress Requests PermalinkURL: http://example.com/2009/01/hello-world becomes: http://example.com/index.php? year=2009& monthnum=01& name=hello-world
- 31. Custom WP RequestInstead of making an AJAX call to: http://example.com/wp-content/plugins/wcpdx/ajax.php we want a URL like: http://example.com/index.php?wcpdx=ajax-handler
- 32. Custom WP Requestsfunction wcpdx_parse_request($wp) { // only process requests with "wcpdx=ajax-handler" if (array_key_exists('wcpdx', $wp->query_vars) && $wp->query_vars['wcpdx'] == 'ajax-handler') { // process the request. } } add_action('parse_request', 'wcpdx_parse_request'); function wcpdx_query_vars($vars) { $vars[] = 'wcpdx'; return $vars; } add_filter('query_vars', 'wcpdx_query_vars');