会话变量没有进入另一个内部文件PHP

Question

I have one login form when user give username and password it leads to login.php file

session_start();
if ( isset( $_POST['username'], $_POST['password'] ) ) {  
    $user   = $_POST['username'] ;
    $pass   = $_POST['password'] ;
    $query  = " MY QUERY "; 
    $result = mysql_query($query) or die('SQL ERROR:'.mysql_error()); 
    $row    = mysql_fetch_assoc($result);   
    if ($row) {         
        echo "query successfull wrote to DB";       
        unset($_SESSION);
        $userName = $row['firstname'].' '.$row['lastname'];
        $_SESSION['userNameSession'] = $userName;
        $_SESSION['loginStatus']     = '1';
        header('location:admin/admin.php');
    }else{
        echo "unscccessful login";
        header('location:index.php');
    }
}

When I Try to print the session by print_r($_SESSION) from this file.. it shows the session and its variable with values

Array ( [userNameSession] => full name [loginStatus] => 1 )

In my admin/admin.php (opens when successful login) wrote

    session_start();
    print_r($_SESSION);exit;

if try to print the session by print_r($_SESSION) it shows empty array as Array()

Please help.

Answer 1

Why do you make an unset($_SESSION)? This may cause the session variable is deleted but the session still exists.

If you want to clean $_SESSION['LoginStatus'] and $_SESSION['userNameSession'], better clean one by one (although this is not necessary because you'll rewrite its value later):

unset($_SESSION['LoginStatus']);
unset($_SESSION['userNameSession']);

The code must be like this:

session_start();
if ( !empty($_POST['username']) && !empty($_POST['password']) ) {  
    $user   = $_POST['username'] ;
    $pass   = $_POST['password'] ;
    $query  = " YOUR QUERY "; 
    $result = mysql_query($query) or die('SQL ERROR:'.mysql_error());   
    if (mysql_num_rows($result) > 0) {        
        //DELETE prints BEFORE header()!! -> echo "query successfull wrote to DB"; 
        $row = mysql_fetch_assoc($result);

        unset($_SESSION['userNameSession']);
        unset($_SESSION['loginStatus']);

        $userName = $row['firstname'].' '.$row['lastname'];

        $_SESSION['userNameSession'] = $userName;
        $_SESSION['loginStatus']     = '1';

        header('location:admin/admin.php');
    }else{
        //DELETE prints BEFORE header()!! -> echo "unscccessful login";
        header('location:index.php');
    }
}