如何在php中注销用户 - How to logout a user in php?

我正在制作一个登录系统，我刚刚开始工作，现在我很难为我的网站制作注销功能。它还没有真正托管，所以稍后会提供安全性。我尝试过session_demory和unset的各种用途，但我无法使其发挥作用。如有任何帮助，我们将不胜感激。

我的PHP

<?php
session_start();
/*This is the equivalent of login.php*/
$database = "forum";  // the name of the database.
$server = "localhost";  // server to connect to.
$db_user = "root";  // mysql username to access the database with.
$db_pass = "";  // mysql password to access the database with.
$table = "members";    // the table that this script will set up and use.
$link = mysql_connect($server, $db_user, $db_pass);
mysql_select_db($database,$link);
if (isset($_POST['fsubmitted'])) {
// Get the data passed from the form
$username = $_POST['username'];
$pass = $_POST['pass'];
// Do some basic sanitizing
$username = stripslashes($username);
$pass = stripslashes($pass);
$encryptedpass = md5($pass);
$sql = "SELECT * from members where username = '$username' and password = '$encryptedpass'";
$result = mysql_query($sql);

$count = 0;
$count = mysql_num_rows($result);
if ($count == 1) {
     $_SESSION['loggedIn'] = "true";
    header("Location: index.php"); // This is wherever you want to redirect the user to
    exit();
} else {
     $_SESSION['loggedIn'] = "false";
     echo '<div class="errormsgbox">Your username and password combo was incorrect!</div>';
     var_dump($result);
    echo $sql;
}
}
if ($_SESSION['loggedIn'] = "true") {
    echo '<div class="success">You are now logged in!</div>';
}
if (isset($_SESSION['loggedin']) && (time() - $_SESSION['loggedin'] > 1800)) {
    // last request was more than 30 minutes ago
    session_unset();     // unset $_SESSION variable for the run-time 
    session_destroy();   // destroy session data in storage
}
$_SESSION['loggedin'] = time(); // update last activity time stamp
?>

使用：

session_start();

具有以下任一项：

session_destroy();
session_unset();
unset($_SESSION["loggedin"]);
$_SESSION = array();

我可以在您的代码中看到两个错误：

您尚未开始会话
您没有告诉代码要取消设置/销毁哪个会话

正在启动会话：

将其作为PHP代码的第一行：session_start();

注销

让我们仔细看看这个代码块：

if (isset($_SESSION['loggedin']) && (time() - $_SESSION['loggedin'] > 1800)) {
    // last request was more than 30 minutes ago
    session_unset();     // unset $_SESSION variable for the run-time 
    session_destroy();   // destroy session data in storage
}

您没有告诉代码哪个会话是unset还是destroy！

要做到这一点，必须在括号内包含一个会话变量。

试试这个代码：

if (isset($_SESSION['loggedin']) && (time() - $_SESSION['loggedin'] > 1800)) {
// last request was more than 30 minutes ago
session_unset($_SESSION['loggedin']);     // unset $_SESSION variable for the run-time 
session_destroy($_SESSION['loggedin']);   // destroy session data in storage
}

我所做的只是，告诉代码哪个会话到unset和destroy

更新
如果这对你不太管用，那就试试这个吧。

if (isset($_SESSION['loggedin']) && (time() - $_SESSION['loggedin'] > 1800)) {
// last request was more than 30 minutes ago
unset($_SESSION['loggedin']);     // unset $_SESSION variable for the run-time 
$_SESSION['loggedin'] = "false";
}

另一个值得注意的好东西是有一个注销按钮。这在这里解释：注销按钮php

我希望这能帮助你，如果我能提供进一步的帮助，请告诉我！

在您的脚本中注销某人，只需：

session_start();
unset($_SESSION);
session_destroy();

您还应该在上面显示的login.php中的某个时刻调用session_start()。

我会尝试使用这个函数：

function logout(){
    if(session_id() == '') { // start session if none found
        session_start();
    }
    session_unset();         
    session_destroy();
    unset($_SESSION['loggedIn']);
}

使用这个函数所需要做的就是调用logout（）；您希望将该人员注销的位置。