Backend DevelopmentPHP TutorialHow to use session in PHP to save user login information and session user login_PHP tutorial
How to use session in PHP to save user login information, session user login
Session is a very important thing in PHP. For example, our user login generally uses session. Things, compared to cookies, sessions are much safer. At the same time, our shopping carts often use sessions for temporary record storage.
Use session to save page login information
1. Database connection configuration page: connectvars.php
<?php
//数据库的位置
define('DB_HOST', 'localhost');
//用户名
define('DB_USER', 'root');
//口令
define('DB_PASSWORD', '19900101');
//数据库名
define('DB_NAME','test') ;
?>
2. Login page: logIn.php
<?php
//插入连接数据库的相关信息
require_once 'connectvars.php';
//开启一个会话
session_start();
$error_msg = "";
//如果用户未登录，即未设置$_SESSION['user_id']时，执行以下代码
if(!isset($_SESSION['user_id'])){
if(isset($_POST['submit'])){//用户提交登录表单时执行如下代码
$dbc = mysqli_connect(DB_HOST,DB_USER,DB_PASSWORD,DB_NAME);
$user_username = mysqli_real_escape_string($dbc,trim($_POST['username']));
$user_password = mysqli_real_escape_string($dbc,trim($_POST['password']));
if(!empty($user_username)&&!empty($user_password)){
//MySql中的SHA()函数用于对字符串进行单向加密
$query = "SELECT user_id, username FROM mismatch_user WHERE username = '$user_username' AND "."password = SHA('$user_password')";
//用用户名和密码进行查询
$data = mysqli_query($dbc,$query);
//若查到的记录正好为一条，则设置SESSION，同时进行页面重定向
if(mysqli_num_rows($data)==1){
$row = mysqli_fetch_array($data);
$_SESSION['user_id']=$row['user_id'];
$_SESSION['username']=$row['username'];
$home_url = 'loged.php';
header('Location: '.$home_url);
}else{//若查到的记录不对，则设置错误信息
$error_msg = 'Sorry, you must enter a valid username and password to log in.';
}
}else{
$error_msg = 'Sorry, you must enter a valid username and password to log in.';
}
}
}else{//如果用户已经登录，则直接跳转到已经登录页面
$home_url = 'loged.php';
header('Location: '.$home_url);
}
?>
<html>
<head>
<title>Mismatch - Log In</title>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<h3 id="Msimatch-Log-In">Msimatch - Log In</h3>
<!--通过$_SESSION['user_id']进行判断，如果用户未登录，则显示登录表单，让用户输入用户名和密码-->
<?php
if(!isset($_SESSION['user_id'])){
echo '<p class="error">'.$error_msg.'</p>';
?>
<!-- $_SERVER['PHP_SELF']代表用户提交表单时，调用自身php文件 -->
<form method = "post" action="<?php echo $_SERVER['PHP_SELF'];?>">
<fieldset>
<legend>Log In</legend>
<label for="username">Username:</label>
<!-- 如果用户已输过用户名，则回显用户名 -->
<input type="text" id="username" name="username"
value="<?php if(!empty($user_username)) echo $user_username; ?>" />
<br/>
<label for="password">Password:</label>
<input type="password" id="password" name="password"/>
</fieldset>
<input type="submit" value="Log In" name="submit"/>
</form>
<?php
}
?>
</body>
</html>
3. Login page: logged.php
<?php
//使用会话内存储的变量值之前必须先开启会话
session_start();
//使用一个会话变量检查登录状态
if(isset($_SESSION['username'])){
echo 'You are Logged as '.$_SESSION['username'].'<br/>';
//点击“Log Out”,则转到logOut页面进行注销
echo '<a href="logOut.php"> Log Out('.$_SESSION['username'].')</a>';
}
/**在已登录页面中，可以利用用户的session如$_SESSION['username']、
* $_SESSION['user_id']对数据库进行查询，可以做好多好多事情*/
?>
4. Logout session page: logOut.php (redirect to lonIn.php after logout)
<?php
//即使是注销时，也必须首先开始会话才能访问会话变量
session_start();
//使用一个会话变量检查登录状态
if(isset($_SESSION['user_id'])){
//要清除会话变量，将$_SESSION超级全局变量设置为一个空数组
$_SESSION = array();
//如果存在一个会话cookie，通过将到期时间设置为之前1个小时从而将其删除
if(isset($_COOKIE[session_name()])){
setcookie(session_name(),'',time()-3600);
}
//使用内置session_destroy()函数调用撤销会话
session_destroy();
}
//location首部使浏览器重定向到另一个页面
$home_url = 'logIn.php';
header('Location:'.$home_url);
?>
Okay, the above code is the entire content of this article. The code is very simple, and there are annotations in many places. If there is anything you don’t understand, please leave me a message and I will reply to you as soon as possible. Thanks!
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