public function createUrl(\Twig_Environment $env, $value = null, $options = null)
    {
        $base = '';
        $baseurl = $env->getGlobals()['site']['baseurl'];
        $hash = md5($env->getGlobals()['site']['time']);
        $canonical = null;
        $addhash = true;

        if (isset($options['canonical'])) {
            $canonical = $options['canonical'];
        }
        if (is_bool($options)) { // backward compatibility
            $canonical = $options;
        }
        if (isset($options['addhash'])) {
            $addhash = $options['addhash'];
        }

        if ($env->getGlobals()['site']['canonicalurl'] === true || $canonical === true) {
            $base = rtrim($baseurl, '/');
        }
        if ($canonical === false) {
            $base = '';
        }

        if ($value instanceof Page) {
            $value = $value->getPermalink();
            if (false !== strpos($value, '.')) { // file URL (with a dot for extension)
                $url = $base.'/'.ltrim($value, '/');
            } else {
                $url = $base.'/'.ltrim(rtrim($value, '/').'/', '/');
            }
        } else {
            if (preg_match('~^(?:f|ht)tps?://~i', $value)) { // external URL
                $url = $value;
            } elseif (false !== strpos($value, '.')) { // file URL (with a dot for extension)
                $url = $base.'/'.ltrim($value, '/');
                if ($addhash) {
                    $url .= '?'.$hash;
                }
            } else {
                $value = $this->slugifyFilter($value);
                $url = $base.'/'.ltrim(rtrim($value, '/').'/', '/');
            }
        }

        return $url;
    }