//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')";
$data = mysqli_query($dbc,$query);
//用用户名和密码进行查询,若查到的记录正好为一条,则设置SESSION和COOKIE,同时进行页面重定向
if(mysqli_num_rows($data)==1){
$row = mysqli_fetch_array($data);
$_SESSION['user_id']=$row['user_id'];
$_SESSION['username']=$row['username'];
setcookie('user_id',$row['user_id'],time()+(60*60*24*30));
setcookie('username',$row['username'],time()+(60*60*24*30));
$home_url = 'loged.php';
header('Location: '.$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);
}
?>
Mismatch - Log In
Msimatch - Log In
if(!isset($_SESSION['user_id'])){
echo '
'.$error_msg.'
';
?>
}
?>
//使用会话内存储的变量值之前必须先开启会话
session_start();
//如果会话没有被设置,查看是否设置了cookie
if(!isset($_SESSION['user_id'])){
if(isset($_COOKIE['user_id'])&&isset($_COOKIE['username'])){
//用cookie给session赋值
$_SESSION['user_id']=$_COOKIE['user_id'];
$_SESSION['username']=$_COOKIE['username'];
}
}
//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'].'
';
echo '
Log Out('.$_SESSION['username'].') ';
}
/**在已登录页面中,可以利用用户的session如$_SESSION['username']、
* $_SESSION['user_id']对数据库进行查询,可以做好多好多事情*/
?>