WP-Mix

Massive round-up of PHP and WordPress techniques for getting various directory and file path information. This is a mega-reference aimed at PHP/WordPress developers.

Note: these snippets are designed for straight-up copy/pasting into any PHP or plugin script. The results should be well-formatted and easy to read.

PHP: Get file paths

Working with or without WordPress, and assuming we are including the following snippets in a plugin directory named /simple-ajax-chat/ (this is just an example; you can include these snippets in any PHP script located in any directory):

echo 'basename(dirname(__FILE__)) = ' . basename(dirname(__FILE__)) . "\n"; // = simple-ajax-chat
echo '$_SERVER["PHP_SELF"] = '        . $_SERVER["PHP_SELF"]        . "\n"; // = /wp-admin/plugins.php
echo '$_SERVER["DOCUMENT_ROOT"] = '   . $_SERVER["DOCUMENT_ROOT"]   . "\n"; // = /var/www/path/example.com/httpdocs
echo 'dirname(__FILE__) = '           . dirname(__FILE__)           . "\n"; // = /var/www/path/example.com/httpdocs/wp-content/plugins/simple-ajax-chat
echo 'getcwd() = '                    . getcwd()                    . "\n"; // = /var/www/path/example.com/httpdocs/wp-admin
echo '__FILE__ = '                    . __FILE__                    . "\n"; // = /var/www/path/example.com/httpdocs/wp-content/plugins/simple-ajax-chat/simple-ajax-chat.php

These snippets are entirely PHP, so they work in any directory, with or without WordPress. Note however that basename(dirname(__FILE__)) returns the current directory name, so if your script is in a subdirectory, you can get the parent directory name by adding another dirname(), like so: basename(dirname(dirname(__FILE__))).

WP: Get plugin paths

Working with WordPress, and assuming we are including the following snippets in a plugin directory named /simple-ajax-chat/ (this is just an example, you can include these snippets in any WordPress plugin):

echo 'dirname(plugin_basename(__FILE__)) = ' . dirname(plugin_basename(__FILE__)) . "\n"; // = simple-ajax-chat
echo 'plugin_basename(dirname(__FILE__)) = ' . plugin_basename(dirname(__FILE__)) . "\n"; // = simple-ajax-chat
echo 'plugin_basename(__FILE__) = '          . plugin_basename(__FILE__)          . "\n"; // = simple-ajax-chat/simple-ajax-chat.php
echo 'WP_PLUGIN_DIR = '                      . WP_PLUGIN_DIR                      . "\n"; // = /var/www/path/example.com/httpdocs/wp-content/plugins
echo 'plugin_dir_path(__FILE__) = '          . plugin_dir_path(__FILE__)          . "\n"; // = /var/www/path/example.com/httpdocs/wp-content/plugins/simple-ajax-chat/

Note: to get the path for the plugin in which the script is included, use plugin_dir_path(). But if you need to get the path of a some other plugin, you can use WP_PLUGIN_DIR.

WP: Get plugin URLs

Working with WordPress, and assuming we are including the following snippets in a plugin directory named /simple-ajax-chat/ (this is just an example, you can include these snippets in any WordPress plugin):

echo 'plugins_url()'                                   . plugins_url()                                   . "\n"; // = http://example.com/wp-content/plugins
echo 'plugin_dir_url(__FILE__) = '                     . plugin_dir_url(__FILE__)                        . "\n"; // = http://example.com/wp-content/plugins/simple-ajax-chat/
echo 'plugins_url('images/wp.png', __FILE__)'          . plugins_url('images/wp.png', __FILE__)          . "\n"; // = http://example.com/wp-content/plugins/simple-ajax-chat/images/wp.png
echo 'plugins_url('images/wp.png', dirname(__FILE__))' . plugins_url('images/wp.png', dirname(__FILE__)) . "\n"; // = http://example.com/wp-content/plugins/images/wp.png

Example: Combining these different techniques, here is a way to get the current plugin URL from a script that is included in a subdirectory, say, /simple-ajax-chat/inc/myscript.php

echo plugins_url(basename(dirname(dirname(__FILE__)))) .'/css/sac.css';

..which outputs:

http://example.com/wp-content/plugins/simple-ajax-chat/css/sac.css

Again, the best way to see how these snippets work is to copy/paste them into your WordPress plugin or PHP script (depending on the snippet), and then check the results.

Also check out this useful post at the WP Codex.

WP-Mix File-Path Trilogy

• Getting Path Info with PHP and WordPress
• PHP Get Absolute Path, Document Root, Base URL
• Include files from subdirectory, parent directory