public function setPrefix($prefix)
    {
        if ($prefix != '') {
            $urlParts = parse_url($prefix);

            // Since PHP 5.4.7 parse_url will return host when url scheme is ommited.
            // This allows urls like //static.example.com to be used
            if (isset($urlParts['scheme']) || isset($urlParts['host'])) {
                $prefix = rtrim($prefix, '/') . '/';
            } else {
                $prefix = '/' . trim($prefix, '/') . '/';
            }
        }

        $this->prefix = $prefix;
    }