public function getRequestIp()
    {
        $headers = [
            'HTTP_CLIENT_IP',
            'HTTP_X_FORWARDED_FOR',
            'HTTP_X_FORWARDED',
            'HTTP_FORWARDED_FOR',
            'HTTP_FORWARDED',
            'REMOTE_ADDR',
        ];
        foreach ($headers as $header) {
            if ($this->server($header) !== false) {
                return $this->server($header);
            }
        }

        return 'UNKNOWN';
    }