PHP会话被自动删除

Question

我有一个带有会话的登录脚本，但我的问题是，当用户登录了几分钟后，他们会因某种原因自动注销。

这是我正在使用的完整登录脚本：

class session {

    // Start the session
    function sec_session_start() {
            $session_name = 'nopedotjava'; // Set a custom session name
            $secure = false; // Set to true if using https.
            $httponly = true; // This stops javascript being able to access the session id. 
            ini_set('session.use_only_cookies', 1); // Forces sessions to only use cookies. 
            ini_set('session.cookie_lifetime', 60 * 60 * 24 * 7);
            ini_set('session.gc_maxlifetime', 60 * 60 * 24 * 7);
            ini_set('session.save_path', '/customers/7/7/e/****.com/httpd.www/jobb/sessions');
            $cookieParams = session_get_cookie_params(); // Gets current cookies params.
            session_set_cookie_params($cookieParams["lifetime"], $cookieParams["path"], $cookieParams["domain"], $secure, $httponly); 
            session_name($session_name); // Sets the session name to the one set above.
            session_start(); // Start the php session
            session_regenerate_id(true); // regenerated the session, delete the old one.     
            echo $cookieParams['lifetime'];
    }

    // Login Function
    function login($username, $password, $mysqli) {
        // Using prepared Statements means that SQL injection is not possible.
        $stmt = $mysqli->stmt_init();
        if ($stmt->prepare("SELECT id, password FROM workers WHERE username = ? LIMIT 1")) { 
            $stmt->bind_param('s', $username); // Bind "$username" to parameter.
            $stmt->execute(); // Execute the prepared query.
            $stmt->store_result();
            $stmt->bind_result($uid, $db_password); // get variables from result.
            $stmt->fetch();
            $key = "*************************************";
            $newPassword = pass_decrypt($db_password, $key); // encode password

            if($stmt->num_rows == 1) { // If the user exists
                if($newPassword == $password) { // Check if the password in the database matches the password the user submitted. 
                    // Password is correct!
                    $user_browser = $_SERVER['HTTP_USER_AGENT']; // Get the user-agent string of the user.
                    $uid = preg_replace("/[^0-9]+/", "", $uid); // XSS protection as we might print this value
                    $_SESSION['uid'] = $uid; 
                    $username = preg_replace("/[^a-zA-Z0-9_\-]+/", "", $username); // XSS protection as we might print this value
                    $_SESSION['username'] = $username;
                    $_SESSION['login_string'] = hash('sha512', $db_password.$user_browser);
                    // Login successful.
                    return true;    
                }
                else{
                    // Password is not correct
                    // We record this attempt in the database
                    return false;
                }
            }
        }
        else {
            // User do not exist
            return false;
        }
    }

    // Check if a user is logged in or not.
    function login_check($mysqli) {
        // Check if all session variables are set
        if(isset($_SESSION['uid'], $_SESSION['username'], $_SESSION['login_string'])) {
            $uid = $_SESSION['uid'];
            $login_string = $_SESSION['login_string'];
            $username = $_SESSION['username'];
            $user_browser = $_SERVER['HTTP_USER_AGENT']; // Get the user-agent string of the user.
            $stmt = $mysqli->stmt_init();
            if ($stmt->prepare("SELECT password FROM workers WHERE id = ? LIMIT 1")) { 
                $stmt->bind_param('i', $uid); // Bind "$uid" to parameter.
                $stmt->execute(); // Execute the prepared query.
                $stmt->store_result();
                if($stmt->num_rows == 1) { // If the user exists
                    $stmt->bind_result($password); // get variables from result.
                    $stmt->fetch();
                    $login_check = hash('sha512', $password.$user_browser);
                    if($login_check == $login_string) {
                        // Logged In!!!!
                        return true;
                    } 
                    else{
                        // Not logged in
                        return false;
                    }
                }
                else{
                    // Not logged in
                    return false;
                }
            } 
            else{
                // Not logged in
                return false;
            }
        }
        else{
            // Not logged in
            return false;
        }
    }
}

正如您所看到的，我已经更改了ini设置，因此cookie和会话生命周期很长。 session.gc_probability / session.gc_divisor是1/1000。 任何线索为什么会发生这种情况？提前谢谢！