get_shortcode_regex( array $tagnames = null ): string

Retrieves the shortcode regular expression for searching.

Description

The regular expression combines the shortcode tags in the regular expression in a regex class.

The regular expression contains 6 different sub matches to help with parsing.

1 – An extra [ to allow for escaping shortcodes with double [[]] 2 – The shortcode name 3 – The shortcode argument list 4 – The self closing / 5 – The content of a shortcode when it wraps some content.
6 – An extra ] to allow for escaping shortcodes with double [[]]

Parameters

$tagnamesarrayoptional
List of shortcodes to find. Defaults to all registered shortcodes.

Default:null

Return

string The shortcode search regular expression

Source

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
}

Changelog

VersionDescription
4.4.0Added the $tagnames parameter.
2.5.0Introduced.

User Contributed Notes

  1. Skip to note 3 content

    Example

    /**
     * Detect shortcodes in the global $post.
     */
    function wpdocs_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] )
    	) {
    		// shortcode is being used
    	}
    }
    add_action( 'wp', 'wpdocs_detect_shortcode' );

    This can only be used when $post is available. ‘wp’ is the earliest action you can hook into to get access to it.

    The following code is an adjustment of the first example, but able to also search all posts on the index page.

    /**
     * Detect shortcodes in the global $post.
     */
    function wpdocs_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] )
    		) {
    			// enque my css and js
    			break;	
    		}    
    	}
    }
    add_action( 'wp', 'wpdocs_detect_shortcode' );
  2. Skip to note 4 content

    Each element of the $matches array given to you by preg_match_all() is itself an array. If your post content contains multiple shortcodes, each of those arrays contains one element for each shortcode. This sort of code gets them.

    function wpdocs_detect_shortcode() {
    	global $post;
    
    	$pattern = get_shortcode_regex();
    
    	if ( preg_match_all( '/' . $pattern . '/s', $post->post_content, $matches ) && array_key_exists( 2, $matches ) ) {
    		$shortcode_count  = count( $matches[2] );
    		$shortcodes_array = $matches[2];
    		$atts_array       = $matches[3];
    
    		for ( $i = 0; $i < $shortcode_count; $i++ ) {
    			$shortcode = $shortcodes_array[ $i ];
    			$atts      = shortcode_parse_atts( $atts_array[ $i ] );
    		}
    	}
    }

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