Shortcode Regex Finder

shortcode-regex-finder.php

<?php
/**
 * Plugin Name: Shortcode Regex Finder
 * Plugin URI:
 * Description: This plugin creates the regex WordPress would use to find a specific shortcode in content.
 * Author: keesiemijer
 * License: GPL v2
 * Version: 1.0
 * Text Domain: shortcode-regex-finder
 */

// Load the textdomain
add_action( 'init', 'pluginception_load_textdomain' );
function pluginception_load_textdomain() {
	load_plugin_textdomain( 'shortcode-regex-finder', false, dirname( plugin_basename( __FILE__ ) ) );
}

add_action( 'admin_menu', 'shortcode_regex_finder_admin_menu' );
function shortcode_regex_finder_admin_menu() {
	add_options_page(
		__( 'Shortcode Regex Finder', 'shortcode-regex-finder' ),
		__( 'Shortcode Regex Finder', 'shortcode-regex-finder' ),
		'manage_options',
		'shortcode-regex-finder.php',
		'shortcode_regex_finder_admin_page' );
}

function shortcode_regex_finder_admin_page() {
	$results = shortcode_regex_finder_get_regex();
	$value   = isset( $results['shortcode'] ) ? $results['shortcode'] : '';

	echo '<div class="wrap">';
	echo '<h2>' . __( 'Shortcode Regex Finder', 'pluginception' ) . '</h2>';
	echo '<p>' . __( 'This plugin creates the same regular expression WordPress would use to find a specific shortcode.', 'pluginception' ) . '</p>';
	settings_errors();
	echo '<form method="post" action="">';
	wp_nonce_field( 'shortcode_regex_finder_nonce' );
	echo "<table class='form-table'><tr valign='top'><th scope='row'>Shortcode Name</th>";
	echo "<td><input class='regular-text' type='text' name='shortcode_search' value='{$value}'>";
	echo "<p class='description'>Shortcode name <strong>without</strong> the brackets.</p></td></tr></table>\n";
	submit_button( __( 'Create the shortcode regex!', 'shortcode-regex-finder' ) );
	echo '</form>';
	if ( $results && is_array( $results ) ) {
		echo '<p>' . sprintf( 'Regex for the shortcode: %s', '<strong>' . $results['shortcode'] . '</strong>' ) . '</p>';
		echo '<pre style="border:1px solid #ddd;padding:1em;background-color:#fff;">';
		print_r( $results['regex'] );
		echo '</pre>';
	}
	echo '</div>';
}

function shortcode_regex_finder_get_regex() {

	if ( 'POST' != $_SERVER['REQUEST_METHOD'] ) {
		return false;
	}

	check_admin_referer( 'shortcode_regex_finder_nonce' );

	$_POST = stripslashes_deep( $_POST );

	if ( isset( $_POST['shortcode_search'] ) ) {
		$shortcode = sanitize_text_field ( trim( $_POST['shortcode_search'] ) );

		if ( empty( $shortcode ) ) {
			add_settings_error( 'shortcode_regex_finder', 'shortcode_search', __( 'Please submit a shortcode name', 'shortcode-regex-finder' ), 'error' );
			return false;
		}

		global $shortcode_tags;
		$temp_shortcode_tags = $shortcode_tags;
		$shortcode_tags      = array( $shortcode => '' );
		$regex               = '/' . get_shortcode_regex() . '/s';
		$shortcode_tags      = $temp_shortcode_tags;
		add_settings_error( 'shortcode_regex_finder', 'shortcode_search', sprintf( 'Regex created for the shortcode: %s', '<strong>' . $shortcode . '</strong>' ), 'update' );
		return array( 'regex' => $regex, 'shortcode' => $shortcode );
	}

	return false;
}

This plugin finds the regex used by WordPress to find a single shortcode in post content. See https://keesiemeijer.wordpress.com/2015/05/25/how-to-remove-specific-shortcodes-from-post-content/