Shortcode.php

<?php
/**
 * PHP5
 */

/**
 * Shortcode class
 * 
 * This is an implementation of the WordPress shortcodes
 * to be used as a standalone functionality, outside of
 * WordPress.
 * 
 * @author Leonid Mamchenkov <leonidm@easy-forex.com>
 */
class Shortcode {

	/**
	 * Associative array of shortcodes and their
	 * respective callbacks
	 */
	protected $callbacks;

	/**
	 * Constructor
	 */
	public function __construct() {
		$this->callbacks = $this->loadCallbacks();
	}

	/**
	 * Load callbacks for all known shortcodes
	 * 
	 * Find all shortcode classes, check that they all implement
	 * the iShortcode interface, and load their callbacks for 
	 * supported shortcodes.
	 * 
	 * @return array Associative array of shortcodes and their respective callbacks
	 */
	public function loadCallbacks() {
		$result = array();
		
		$path = dirname(__FILE__) . DIRECTORY_SEPARATOR . 'Shortcodes';
		foreach (new DirectoryIterator($path) as $fileInfo) {
			
			if ($fileInfo->isDot()) {
				continue;
			}
			if (!$fileInfo->isDir()) {
				continue;
			}
			
			$shortcode = $fileInfo->getBasename();
			$shortcode_class_path = $fileInfo->getPathname() . DIRECTORY_SEPARATOR . $shortcode . '.php';
			
			if (!file_exists($shortcode_class_path) || !is_readable($shortcode_class_path)) {
				continue;
			}
			
			require_once $shortcode_class_path;
			if (!in_array('iShortcode', class_implements($shortcode))) {
				continue;
			}
			
			$shortcode_callbacks = $shortcode::getCallbacks();
			$result = array_merge($result, $shortcode_callbacks);
		}

		return $result;
	}

	/**
	 * Parse shortcodes in given content
	 * 
	 * @param string $content Content to parse for shortcodes
	 * @return string
	 */
	public function parse($content) {
		$result = $content;

		$shortcodes = $this->getShortcodeList($content);
		foreach ($shortcodes as $shortcode) {
			// Only process known/supported shortcodes
			if (in_array($shortcode, array_keys($this->callbacks))) {
				$regexp = $this->getShortcodeRegexp($shortcode);
				$result = preg_replace_callback("/$regexp/s", array($this, 'parseSingle'), $result);
			}
		}

		return $result;
	}

	/**
	 * Parse single shortcode
	 * 
	 * Borrowed from WordPress wp/wp-includes/shortcode.php
	 * 
	 * @param array $m Shortcode matches
	 * @return string
	 */
	protected function parseSingle($m) {

		// allow [[foo]] syntax for escaping a tag
		if ( $m[1] == '[' && $m[6] == ']' ) {
			return substr($m[0], 1, -1);
		}

		$tag = $m[2];
		$attr = $this->shortcodeParseAtts( $m[3] );

		if ( isset( $m[5] ) ) {
			// enclosing tag - extra parameter
			return $m[1] . call_user_func( $this->callbacks[$tag], $attr, $m[5], $tag ) . $m[6];
		} else {
			// self-closing tag
			return $m[1] . call_user_func( $this->callbacks[$tag], $attr, null,  $tag ) . $m[6];
		}

	}

	/**
	 * Get the list of all shortcodes found in given content
	 * 
	 * @param string $content Content to process
	 * @return array
	 */
	protected function getShortcodeList($content){
		$result = array();
		
		preg_match_all("/\[([A-Za-z_]+[^\ \]]+)/", $content, $matches);
		if (!empty($matches[1])) {
			foreach ($matches[1] as $match) {
				$result[$match] = $match;
			}
		}
		return $result;
	}

	/**
	 * Parses attributes from a shortcode
	 * 
	 * Borrowed from WordPress wp/wp-includes/shortcode.php
	 * 
	 * @param string $text
	 * @return array
	 */
	protected function shortcodeParseAtts($text) {
		$atts = array();
		$pattern = '/(\w+)\s*=\s*"([^"]*)"(?:\s|$)|(\w+)\s*=\s*\'([^\']*)\'(?:\s|$)|(\w+)\s*=\s*([^\s\'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|(\S+)(?:\s|$)/';
		$text = preg_replace("/[\x{00a0}\x{200b}]+/u", " ", $text);
		if ( preg_match_all($pattern, $text, $match, PREG_SET_ORDER) ) {
			foreach ($match as $m) {
				if (!empty($m[1]))
					$atts[strtolower($m[1])] = stripcslashes($m[2]);
				elseif (!empty($m[3]))
					$atts[strtolower($m[3])] = stripcslashes($m[4]);
				elseif (!empty($m[5]))
					$atts[strtolower($m[5])] = stripcslashes($m[6]);
				elseif (isset($m[7]) and strlen($m[7]))
					$atts[] = stripcslashes($m[7]);
				elseif (isset($m[8]))
					$atts[] = stripcslashes($m[8]);
			}
		} else {
			$atts = ltrim($text);
		}
		return $atts;
	}
	
	/**
	 * Returns a regular expression for matching a shortcode tag
	 * 
	 * Borrowed from WordPress wp/wp-includes/shortcode.php
	 * 
	 * @return string
	 */
	protected function getShortcodeRegexp($tagregexp) {

		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 brocket for escaping shortcodes: [[tag]]
	}

}