php实现登录退出代码
PHP 登录功能实现
创建登录表单页面 login.php，包含用户名和密码输入框：
<form action="auth.php" method="post">
<input type="text" name="username" placeholder="用户名">
<input type="password" name="password" placeholder="密码">
<button type="submit">登录</button>
</form>创建认证处理文件 auth.php，验证用户凭证：
session_start();
$valid_username = 'admin'; // 示例用户名
$valid_password = '123456'; // 示例密码
if ($_POST['username'] === $valid_username && $_POST['password'] === $valid_password) {
$_SESSION['logged_in'] = true;
$_SESSION['username'] = $_POST['username'];
header('Location: dashboard.php');
} else {
header('Location: login.php?error=1');
}PHP 会话验证
在受保护页面 dashboard.php 中验证会话：
session_start();
if (!isset($_SESSION['logged_in']) || $_SESSION['logged_in'] !== true) {
header('Location: login.php');
exit;
}
echo "欢迎, ".$_SESSION['username'];PHP 退出功能实现
创建退出处理文件 logout.php：
session_start();
session_unset();
session_destroy();
header('Location: login.php');
exit;数据库版本登录验证
使用MySQL数据库验证的示例代码：
session_start();
$conn = new mysqli('localhost', 'username', 'password', 'database');
$username = $conn->real_escape_string($_POST['username']);
$password = $_POST['password'];
$result = $conn->query("SELECT * FROM users WHERE username='$username'");
if ($result->num_rows === 1) {
$user = $result->fetch_assoc();
if (password_verify($password, $user['password'])) {
$_SESSION['user_id'] = $user['id'];
$_SESSION['username'] = $user['username'];
header('Location: dashboard.php');
}
}
header('Location: login.php?error=1');安全注意事项
密码应使用PHP的password_hash()函数进行哈希存储：
$hashed_password = password_hash($_POST['password'], PASSWORD_DEFAULT);添加CSRF保护，在登录表单中：
$_SESSION['token'] = bin2hex(random_bytes(32));<input type="hidden" name="token" value="<?php echo $_SESSION['token']; ?>">在认证处理中验证CSRF令牌：
if (!hash_equals($_SESSION['token'], $_POST['token'])) {
die('CSRF验证失败');
}
