/**
* Gets all callbacks for a hook.
*
* @see https://wpcodebook.com/wordpress-get-hook-callbacks/
* @see https://developer.wordpress.org/reference/classes/wp_hook/
* @see https://stackoverflow.com/questions/5224209/wordpress-how-do-i-get-all-the-registered-functions-for-the-content-filter
*/
function wpcodebook_hook_callbacks( $hook ) {
global $wp_filter;
return $wp_filter[ $hook ]->callbacks ?? array();
}Example
Print all callbacks for the the_content filter:
$callbacks = wpcodebook_hook_callbacks( 'the_content' );
echo '<pre>';
foreach ( $callbacks as $priority => $_callbacks ) {
foreach ( $_callbacks as $callback_id => $callback_data ) {
$callback = $callback_id;
if ( isset( $callback_data['function'] ) ) {
if ( is_array( $callback_data['function'] ) ) {
$callback = sprintf( '%s::%s',
get_class( $callback_data['function'][0] ),
$callback_data['function'][1]
);
} else {
$callback = print_r( $callback_data['function'], true );
}
}
echo "{$callback}() [{$priority}]" . PHP_EOL;
}
}
echo '</pre>';Output (in the function [priority] format):
WP_Embed::run_shortcode() [8] WP_Embed::autoembed() [8] do_blocks() [9] wptexturize() [10] wpautop() [10] shortcode_unautop() [10] prepend_attachment() [10] wp_replace_insecure_home_url() [10] capital_P_dangit() [11] do_shortcode() [11] wp_filter_content_tags() [12] convert_smilies() [20]