好吧，我明白上面的答案是正确的，但他们是在应用程序级别，为什么我们不简单地使用.htaccess文件设置过期时间?

<IfModule mod_php5.c>
    #Session timeout
    php_value session.cookie_lifetime 1800
    php_value session.gc_maxlifetime 1800
</IfModule>

这篇文章展示了控制会话超时的几种方法:http://bytes.com/topic/php/insights/889606-setting-timeout-php-sessions

恕我直言，第二个选择是一个很好的解决方案:

<?php
/***
 * Starts a session with a specific timeout and a specific GC probability.
 * @param int $timeout The number of seconds until it should time out.
 * @param int $probability The probablity, in int percentage, that the garbage 
 *        collection routine will be triggered right now.
 * @param strint $cookie_domain The domain path for the cookie.
 */
function session_start_timeout($timeout=5, $probability=100, $cookie_domain='/') {
    // Set the max lifetime
    ini_set("session.gc_maxlifetime", $timeout);

    // Set the session cookie to timout
    ini_set("session.cookie_lifetime", $timeout);

    // Change the save path. Sessions stored in teh same path
    // all share the same lifetime; the lowest lifetime will be
    // used for all. Therefore, for this to work, the session
    // must be stored in a directory where only sessions sharing
    // it's lifetime are. Best to just dynamically create on.
    $seperator = strstr(strtoupper(substr(PHP_OS, 0, 3)), "WIN") ? "\\" : "/";
    $path = ini_get("session.save_path") . $seperator . "session_" . $timeout . "sec";
    if(!file_exists($path)) {
        if(!mkdir($path, 600)) {
            trigger_error("Failed to create session save path directory '$path'. Check permissions.", E_USER_ERROR);
        }
    }
    ini_set("session.save_path", $path);

    // Set the chance to trigger the garbage collection.
    ini_set("session.gc_probability", $probability);
    ini_set("session.gc_divisor", 100); // Should always be 100

    // Start the session!
    session_start();

    // Renew the time left until this session times out.
    // If you skip this, the session will time out based
    // on the time when it was created, rather than when
    // it was last used.
    if(isset($_COOKIE[session_name()])) {
        setcookie(session_name(), $_COOKIE[session_name()], time() + $timeout, $cookie_domain);
    }
}

使用下面这样的函数其实很简单。它使用数据库表名'sessions'与字段'id'和'time'。

每次当用户再次访问您的站点或服务时，您都应该调用这个函数来检查它的返回值是否为TRUE。如果是FALSE，用户已经过期，会话将被销毁(注意:这个函数使用一个数据库类来连接和查询数据库，当然你也可以在你的函数中这样做或类似的事情):

function session_timeout_ok() {
    global $db;
    $timeout = SESSION_TIMEOUT; //const, e.g. 6 * 60 for 6 minutes
    $ok = false;
    $session_id = session_id();
    $sql = "SELECT time FROM sessions WHERE session_id = '".$session_id."'";
    $rows = $db->query($sql);
    if ($rows === false) {
        //Timestamp could not be read
        $ok = FALSE;
    }
    else {
        //Timestamp was read succesfully
        if (count($rows) > 0) {
            $zeile = $rows[0];
            $time_past = $zeile['time'];
            if ( $timeout + $time_past < time() ) {
                //Time has expired
                session_destroy();
                $sql = "DELETE FROM sessions WHERE session_id = '" . $session_id . "'";
                $affected = $db -> query($sql);
                $ok = FALSE;
            }
            else {
                //Time is okay
                $ok = TRUE;
                $sql = "UPDATE sessions SET time='" . time() . "' WHERE session_id = '" . $session_id . "'";
                $erg = $db -> query($sql);
                if ($erg == false) {
                    //DB error
                }
            }
        }
        else {
            //Session is new, write it to database table sessions
            $sql = "INSERT INTO sessions(session_id,time) VALUES ('".$session_id."','".time()."')";
            $res = $db->query($sql);
            if ($res === FALSE) {
                //Database error
                $ok = false;
            }
            $ok = true;
        }
        return $ok;
    }
    return $ok;
}

使用时间戳……

<?php
if (!isset($_SESSION)) {
    $session = session_start();
} 
if ($session && !isset($_SESSION['login_time'])) {
    if ($session == 1) {
        $_SESSION['login_time']=time();
        echo "Login :".$_SESSION['login_time'];
        echo "<br>";
        $_SESSION['idle_time']=$_SESSION['login_time']+20;
        echo "Session Idle :".$_SESSION['idle_time'];
        echo "<br>";
    } else{
        $_SESSION['login_time']="";
    }
} else {
    if (time()>$_SESSION['idle_time']){
        echo "Session Idle :".$_SESSION['idle_time'];
        echo "<br>";
        echo "Current :".time();
        echo "<br>";
        echo "Session Time Out";
        session_destroy();
        session_unset();
    } else {
        echo "Logged In<br>";
    }
}
?>

我用了20秒的时间戳使会话过期。

如果你需要30分钟，加1800(30分钟单位秒)…

这让我大开眼界，克里斯托弗·克莱默在2014年写的 https://www.php.net/manual/en/session.configuration.php#115842

在debian(基于)系统上，更改会话。Gc_maxlifetime在运行时没有实际影响。Debian通过设置session.gc_probability=0禁用PHP自己的垃圾收集器。相反，它有一个每30分钟运行一次的cronjob(参见/etc/cron.d/php5)来清理旧的会话。这个cronjob基本上会查看你的php.ini并使用session的值。Gc_maxlifetime来决定清理哪些会话(参见/usr/lib/php5/maxlifetime)。[…]

您可以直接使用DB作为替代。我使用一个DB函数来做这件事，我称之为chk_lgn。

检查登录检查，看看他们是否登录，在这样做的时候，它将检查的日期时间戳设置为用户db行/列中的最后一个活动。

我也会核对时间。这对我来说是有效的，因为我对每个页面都使用这个函数。

附注:我所见过的人中，没有人建议使用纯DB解决方案。