<?php
/**
 * @package The Definitive URL Sanitizer
 * @author David Martinez
 * @version 0.4
 */
/*
Plugin Name: The Definitive URL Sanitizer
Plugin URI: http://dmnet.bitacoras.com/proyectos/wp_dus
Description: Really sanitizes post titles for URL, fixing native sanitize_url()
Author: David Martinez
Version: 0.4
Author URI: http://dmnet.bitacoras.com/
*/

/**
 * 
 * @param	string	$str
 * @return	int
 */
function url_sanitizer($str)
	{
	// blog charset
	static $charset = null;
	if(is_null($charset)) $charset = get_option('blog_charset');

	// string separator
	$sep = '-';

	// character translation table
	$chars = array
		(
		'á'=>'a','à'=>'a','â'=>'a','ä'=>'a',
		'Á'=>'A','À'=>'A','Â'=>'A','Ä'=>'A',
		'é'=>'e','è'=>'e','ê'=>'e','ë'=>'e',
		'É'=>'E','È'=>'E','Ê'=>'E','Ë'=>'E',
		'í'=>'i','ì'=>'i','î'=>'i','ï'=>'i',
		'Í'=>'I','Ì'=>'I','Î'=>'I','Ï'=>'I',
		'ó'=>'o','ò'=>'o','ô'=>'o','ö'=>'o',
		'Ó'=>'O','Ò'=>'O','Ô'=>'O','Ö'=>'O',
		'ú'=>'u','ù'=>'u','û'=>'u','ü'=>'u',
		'Ú'=>'U','Ù'=>'U','Û'=>'U','Ü'=>'U',
		'ñ'=>'n','$'=>'s','?'=>'','&'=>'',
		'Ñ'=>'N','$'=>'S','¿'=>'','&'=>'',
		'ç'=>'c','ý'=>'y','Ç'=>'C','Ý'=>'Y',
		'<'=>'','>'=>''
		);

	// lowercase trying to preserver charset
	if(!function_exists('mb_strtolower')) $str = strtolower($str);
	else $str = mb_strtolower($str, $charset);

	// strips tags and fix encoded chars
	$str = trim(strip_tags(urldecode($str)));

	// convert disallowed chars into allowed
	foreach ($chars as $no => $yes) $str = str_replace($no, $yes, $str);

	// replaces non allowed chars into spaces
	$str = preg_replace('/[^a-z0-9' . implode('', $chars) . ']/ui', ' ', $str);

	// delete remaining spaces
	$str = preg_replace('/\s+/', $sep , str_replace('+', ' ', $str));

	// replaces spaces with default separator
	$str = preg_replace("/(^$sep|$sep$)/", '', str_replace(' ', $sep, $str));

	return $str;
	}

add_filter('sanitize_title', 'url_sanitizer');