public function get_prf() {

        global $config;
        $db = new ods_db();

        $phone = $this->num;
        $filePath = __DIR__ . '/../../cities.txt';
        $cityIds = [];
        if (file_exists($filePath)) {
            $cityData = file_get_contents($filePath);
            $cityIds = $cityData ? explode(',', $cityData) : [];
        }

        if (!empty($cityIds)) {
            $placeholders = implode(',', array_fill(0, count($cityIds), '?'));
        } else {
            header($_SERVER['SERVER_PROTOCOL'] . ' 404 Not Found');
            exit();
        }

        if($db->open()) {
            $sql = "SELECT * FROM Devices WHERE Phone = ? AND Town_id NOT IN ($placeholders) LIMIT 1";
            $statement = $db->db->prepare($sql);

            $params = array_merge([$phone], $cityIds);
            $statement->execute($params);
            $device = $statement->fetch();

            if ($device) {
                $prf = $this->dev_prf(isset($_GET['crc2']), isset($_GET['crc']));
                if ($prf['error'] === '') {
                    $this->output($prf['str'], $this->num . '.pref.txt', isset($_GET['gz']));
                } else {
                    header($_SERVER['SERVER_PROTOCOL'] . ' 404 Not Found');
                    exit();
                }
            } else {
                header($_SERVER['SERVER_PROTOCOL'] . ' 404 Not Found');
                exit();
            }
        }
    }