如何在login.php中插入超时功能？

这是我的LOGIN.php文件：

require_once 'include/DB_Functions.php';
$db = new DB_Functions();
// json响应数组
$response = array("error" => FALSE);
if (isset($_POST['email']) && isset($_POST['password'])) {
    // 获取POST参数
    $email = $_POST['email'];
    $password = $_POST['password'];
    // 通过邮箱和密码获取用户
    $user = $db->getUserByEmailAndPassword($email, $password);
    if ($user != false) {
        // 用户存在
        $response["error"] = FALSE;
        $response["uid"] = $user["unique_id"];
        $response["user"]["name"] = $user["name"];
        $response["user"]["cognome"] = $user["cognome"];
        $response["user"]["email"] = $user["email"];
        $response["user"]["email2"] = $user["email2"];
        $response["user"]["numero_appartamento"] = $user["numero_appartamento"];
        $response["user"]["nome_edificio"] = $user["nome_edificio"];
        $response["user"]["zona_metropolitana"] = $user["zona_metropolitana"];
        $response["user"]["created_at"] = $user["created_at"];
        $response["user"]["updated_at"] = $user["updated_at"];
        header('Content-type: application/json');
        echo json_encode($response);
    } else {
        // 用指定的凭证找不到用户
        $response["error"] = TRUE;
        $response["error_msg"] = "登录凭证错误，请重试！";
        echo json_encode($response);
    }
} else {
    // 缺少必需的POST参数
    $response["error"] = TRUE;
    $response["error_msg"] = "缺少必需的参数邮箱或密码！";
    echo json_encode($response);
}

如何插入一个30分钟的timeout？

提前感谢大家！