get_shortcode_regex() │ WP 2.5.0

Returns a regular expression that is used to find shortcodes in the text.

This function combines all registered shortcode tags into a single regular expression.

Used By: apply_shortcodes(), get_post_galleries(), do_shortcode()
1 time — 0.000015 sec (very fast) | 50000 times — 0.07 sec (speed of light) | PHP 7.0.8, WP 4.6.1

No Hooks.

Returns

String. Regular expression.

Usage

$pattern = get_shortcode_regex( $tagnames );
$tagnames(array) (WP 4.4)
List of shortcodes to find.
Default: null (all registered shortcodes)

Examples

0

#1 What the function returns 

echo get_shortcode_regex();

// outputs about this line, depending on the registered shortcodes
// \[(\[?)(embed|wp_caption|caption|gallery|playlist|audio|video)(?![\w-])([^\]\/]*(?:\/(?!\])[^\]\/]*)*?)(?:(\/)\]|\](?:([^\[]*+(?:\[(?!\/\])[^\[]*+)*+)\[\/\])?)(\]?)

If use the $tagnames parameter:

echo get_shortcode_regex( array('mytag') );

//> \[(\[?)(mytag)(?![\w-])([^\]\/]*(?:\/(?!\])[^\]\/]*)*?)(?:(\/)\]|\](?:([^\[]*+(?:\[(?!\/\])[^\[]*+)*+)\[\/\])?)(\]?)
0

#2 Check if the specific shortcode is used in the post

Let's check if the your-shortcode is present in the text and do something if it is (for example enqueue css styles or js file):

add_action( 'wp', 'your_prefix_detect_shortcode' );

function your_prefix_detect_shortcode(){
	global $post;

	$pattern = get_shortcode_regex();

	if ( preg_match_all( '/'. $pattern .'/s', $post->post_content, $matches )
		&& array_key_exists( 2, $matches )
		&& in_array( 'your-shortcode', $matches[2] )
	) {
		// enqueue css and js
	}
}

This example will work if the global $post variable is defined. wp is the earliest action when we can use it.

See also a special function has_shortcode().

0

#3 Checking for shortcodes in multiple posts

This example is very similar to the previous one, the only difference being that it allows you to check all posts of current request (for example on category page) for the presence of the videoannotation shortcode we need in their content:

add_action( 'wp', 'your_prefix_detect_shortcode' );

function your_prefix_detect_shortcode(){
	global $wp_query;

	$posts = $wp_query->posts;

	$pattern = get_shortcode_regex();

	foreach ( $posts as $post ){

		if ( preg_match_all( '/'. $pattern .'/s', $post->post_content, $matches )
			&& array_key_exists( 2, $matches )
			&& in_array( 'videoannotation', $matches[2] )
		) {
			// enqueue css and js

			break; // we have determined that it is necessary to connect the styles and well...
		}
	}
}

Notes

  • Global. Array. $shortcode_tags

Changelog

Since 2.5.0 Introduced.
Since 4.4.0 Added the $tagnames parameter.

get_shortcode_regex() code WP 6.9.1

wp-includes/shortcodes.php 
function get_shortcode_regex( $tagnames = null ) {
	global $shortcode_tags;

	if ( empty( $tagnames ) ) {
		$tagnames = array_keys( $shortcode_tags );
	}
	$tagregexp = implode( '|', array_map( 'preg_quote', $tagnames ) );

	/*
	 * WARNING! Do not change this regex without changing do_shortcode_tag() and strip_shortcode_tag().
	 * Also, see shortcode_unautop() and shortcode.js.
	 */

	// phpcs:disable Squiz.Strings.ConcatenationSpacing.PaddingFound -- don't remove regex indentation
	return '\\['                             // Opening bracket.
		. '(\\[?)'                           // 1: Optional second opening bracket for escaping shortcodes: [[tag]].
		. "($tagregexp)"                     // 2: Shortcode name.
		. '(?![\\w-])'                       // Not followed by word character or hyphen.
		. '('                                // 3: Unroll the loop: Inside the opening shortcode tag.
		.     '[^\\]\\/]*'                   // Not a closing bracket or forward slash.
		.     '(?:'
		.         '\\/(?!\\])'               // A forward slash not followed by a closing bracket.
		.         '[^\\]\\/]*'               // Not a closing bracket or forward slash.
		.     ')*?'
		. ')'
		. '(?:'
		.     '(\\/)'                        // 4: Self closing tag...
		.     '\\]'                          // ...and closing bracket.
		. '|'
		.     '\\]'                          // Closing bracket.
		.     '(?:'
		.         '('                        // 5: Unroll the loop: Optionally, anything between the opening and closing shortcode tags.
		.             '[^\\[]*+'             // Not an opening bracket.
		.             '(?:'
		.                 '\\[(?!\\/\\2\\])' // An opening bracket not followed by the closing shortcode tag.
		.                 '[^\\[]*+'         // Not an opening bracket.
		.             ')*+'
		.         ')'
		.         '\\[\\/\\2\\]'             // Closing shortcode tag.
		.     ')?'
		. ')'
		. '(\\]?)';                          // 6: Optional second closing bracket for escaping shortcodes: [[tag]].
	// phpcs:enable
}

Shortcodes