public function callbackFunction($route = null, $parameters = [])
    {
        if ($route === null || ! is_string($route)) {
            // Gets URI from current request
            $uri = $this->request->getUri();
        } else {
            // Generates URI from '_route'
            $uri = $this->router->generate(
                $route,
                $parameters,
                Router::ABSOLUTE_URL
            );
        }

        $result = parse_url($uri);

        // When uri contains query string
        if (isset($result['query'])) {

            parse_str($result['query'], $query);

            // Remove callback from query
            $query = array_diff_key($query, ['callback' => null]);
        } else {
            // Return unchanged uri
            return $uri;
        }

        return $result['scheme'].'://'.
               (isset($result['user']) ? $result['user'] : '').
               (isset($result['pass']) ? ':'.$result['pass'].'@' : '').
               $result['host'].
               (isset($result['port']) ? ':'.$result['port'] : '').
               (isset($result['path']) ? $result['path'] : '').
               ($query != [] ? '?'.http_build_query($query) : '').
               (isset($result['fragment']) ? '#'.$result['fragment'] : '');
    }