PHP$\u会话和$\u COOKIE奇怪的行为

我正在尝试将Cookie安装到我的网站中。
我在GitHub上找到了一个脚本：

我已经实现了脚本，并且可以登录。
我可以只使用会话登录，也可以同时使用两个会话登录，并设置“记住我-COOKIE”。

为了测试COOKIE，我将会话设置为1分钟后过期<代码>$expireAfter=1

塞纳里奥：
我登录到网站并选中“记住我”。会话启动并设置cookie。一切都好

##最后一个操作：1秒前
跳过cookie检查：会话已设置

我等待60秒，然后重新加载页面。会话销毁和Cookie读取：

##最后一个动作：108秒前
不活动的会话销毁
曲奇饼阅读
cookie有效格式
cookie右选择器
cookie权利令牌
在DB和cookie中设置新令牌
会话集

我想我找到了问题。

取消设置并销毁会话后。我必须开始新的课程。
奇怪的是，这种事只会每秒钟发生一次。但是添加

session_start（）解决了问题

if(isset($_SESSION['last_action'])){
  $secondsInactive = time() - $_SESSION['last_action'];

  $expireAfterSeconds = $expireAfter * 60;

  $debug.="last action: $secondsInactive seconds ago<br>";
  if($secondsInactive >= $expireAfterSeconds){
    //User has been inactive for too long.
    //Kill their session.
    session_unset();
    session_destroy();
    $debug.="session destroy for inactivity<br>";
  }  
}

...
session_start();
$_SESSION['user'] = $session_data;
...

if（isset（$\u会话['last\u action']））{
$secondsInactive=time（）-$\会话['last\ u action']；
$expireAfterSeconds=$expireAfter*60；
$debug.=“上次操作：$secondsInactive秒前
”；
如果（$secondsInactive>=$expireAfterSeconds）{
//用户处于非活动状态的时间太长。
//终止他们的会话。
session_unset（）；
会话_destroy（）；
$debug.=“会话因不活动而销毁
”；
}  
}
...
会话_start（）；
$\u会话['user']=$SESSION\u数据；
...

<?php
define ("PEPPER",''); //random string for extra salt, use if you want.
define ("WEBSITE",'mydomain.com');  //your web site without http:// without final /
define ("SCRIPTFOLDER",'/login'); //direcory of the script start with a / if you installed the script in the root write just a / never finish with a /

$hosting="localhost"; //your host or localhost
$database="db"; //your database name
$database_user="user"; //your username for database
$database_password="pwd"; //your database password

require_once('pdo_db.php');
//generate random sequence or numbers and letter avoid problems with special chars

function aZ ($n=12) {
    $chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
    $bytes = random_ver($n);
    $result="";
    foreach (str_split($bytes) as $byte) $result .= $chars[ord($byte) % strlen($chars)];
    return $result;
}

//generate random and avoid compatibility problem with php version
function random_ver ($n=10) {
    $v=(int)phpversion()+0;
    if ($v<7) {
        //if php version < 7 use the old function for generate random bytes
        return openssl_random_pseudo_bytes($n);
    }else{
        //random_bytes is better but works only with php version > 7
        return random_bytes($n);
    }
}


// ********************************
// * SESSION TIME UPDATE          *
// ********************************

//Expire the session if user is inactive for 15 minutes or more.
//if u want to check how cookie works let the session id expire (wait X minutes without action, maybe set expireAfter to low value),
//close the browser then open again
$expireAfter = 1;

//Check to see if our "last action" session
//variable has been set.
if(isset($_SESSION['last_action'])){ echo 'IN';
    //Figure out how many seconds have passed
    //since the user was last active.
    $secondsInactive = time() - $_SESSION['last_action'];
    //Convert our minutes into seconds.
    $expireAfterSeconds = $expireAfter * 60;
    //Check to see if they have been inactive for too long.
    $debug.="last action: $secondsInactive seconds ago<br>";

    if($secondsInactive >= $expireAfterSeconds){
        //User has been inactive for too long.
        //Kill their session.
        session_unset();
        session_destroy();
        $debug.="session destroy for inactivity<br>";
    }  
}
//Assign the current timestamp as the user's
//latest activity
$_SESSION['last_action'] = time();

// *********************************
// * CHECK AUTO LOG-IN WITH COOKIE *
// *********************************


//if session is not set, but cookie exists
if (empty($_SESSION['user']) && !empty($_COOKIE['remember']) && $_GET["logout"]!=1) {

    $debug.="cookie read<br>";
    list($selector, $authenticator) = explode(':', urldecode($_COOKIE['remember']));

    //get from database the row with id and token related to selector code in the cookie
    $sql = $db->prepare("SELECT * FROM user_tokens
                         WHERE selector = ? limit 1");
    $sql->bindParam(1, $selector);
    $sql->execute();
    $row = $sql->fetch(PDO::FETCH_ASSOC);

    if (empty($authenticator) or empty($selector)) 
        $debug.="cookie invalid format<br>";

    //continue to check the authenticator only if the selector in the cookie is present in the database
    if (($sql->rowCount() > 0) && !empty($authenticator) && !empty($selector)) { 

        $debug.="cookie valid format<br>";

        // the token provided is like the token in the database
        // the functions password_verify and password_hash add secure salt and avoid timing attacks
        if (password_verify(base64_decode($authenticator), $row['hashedvalidator'])){

            //SET SESSION DATA
            $sql = $db->prepare("SELECT * FROM users WHERE id = ?");
            $sql->bindParam(1, $row['userid']);
            $sql->execute();
            $session_data = $sql->fetch(PDO::FETCH_ASSOC);

            //UNSET VARS
            unset($session_data['password']);

            $_SESSION['user'] = $session_data;

            //update database with a new token for the same selector and set the cookie again
            $authenticator = bin2hex(random_ver(33));
            $res=$db->prepare("UPDATE user_tokens SET hashedvalidator = ? , expires = FROM_UNIXTIME(".(time() + 864000*7).") , ip = ? WHERE selector = ?");
            $res->execute(array(password_hash($authenticator, PASSWORD_DEFAULT, ['cost' => 12]),$_SERVER['REMOTE_ADDR'],$selector));

            //set the cookie
            $setc = setcookie(
                'remember',
                $selector.':'.base64_encode($authenticator),
                time() + 864000*7, //the cookie will be valid for 7 days, or till log-out (if u want change it, modify the login.php file too)
                '/',
                WEBSITE,
                false, // TLS-only set to true if u have a website on https://
                false  // http-only
            );

            $debug.="cookie right selector<br>cookie right token<br>set a new token in DB and in cookie<br>session set ".$_SESSION['user']['usr_fname']."<br>";
        } else { 
            //selector exists but token doesnt match. that could be a secure problem, all selector/authenticator in database for that user will be deleted

            $res=$db->prepare("DELETE FROM user_tokens WHERE userid = ".$row["userid"]);
            $res->execute();
            $debug.="cookie right selector<br>cookie wrong token (all DB entry for that user are deleted)<br>";
        }
    } else {
        $debug.="selector not found in DB<br>";
    }
} else {
    $debug.="skip the cookie check: ";
    if (!empty($_SESSION['user'])) $debug.="session already set<br>";
    if (empty($_COOKIE['remember'])) $debug.="no cookie set<br>";
}
?>

if(isset($_SESSION['last_action'])){
  $secondsInactive = time() - $_SESSION['last_action'];

  $expireAfterSeconds = $expireAfter * 60;

  $debug.="last action: $secondsInactive seconds ago<br>";
  if($secondsInactive >= $expireAfterSeconds){
    //User has been inactive for too long.
    //Kill their session.
    session_unset();
    session_destroy();
    $debug.="session destroy for inactivity<br>";
  }  
}

...
session_start();
$_SESSION['user'] = $session_data;
...