Can't logout in PHP

Question

I'm trying to make a signup / sign-in form in PHP, but I have trouble logging out. I keep getting the following error.

Fatal error: Uncaught ArgumentCountError: Too few arguments to function USER::__construct(), 0 passed in C:\xampp\htdocs\recepten\logout.php on line 4 and exactly 1 expected in C:\xampp\htdocs\recepten\class.user.php:6 Stack trace: #0 C:\xampp\htdocs\recepten\logout.php(4): USER->__construct() #1 {main} thrown in C:\xampp\htdocs\recepten\class.user.php on line 6

Can somebody advise me on what I'm doing what and how to fix the problem?

This is my line of code for the logout script:

<?php
session_start();
require_once 'class.user.php';
$user = new USER();

if(!$user->is_logged_in())
{
    $user->redirect('indexlogin.php');
}

if($user->is_logged_in()!="")
{
    $user->logout(); 
    $user->redirect('indexlogin.php');
}
?>

This is my code for the call-user script:

<?php
class USER
{
    private $db;

    function __construct($DB_con)
    {
        $this->db = $DB_con;
    }

    public function register($fname,$lname,$uname,$umail,$upass)
    {
       try
       {
           $new_password = password_hash($upass, PASSWORD_DEFAULT);

           $stmt = $this->db->prepare("INSERT INTO users(user_name,user_email,user_pass) 
                                                       VALUES(:uname, :umail, :upass)");

           $stmt->bindparam(":uname", $uname);
           $stmt->bindparam(":umail", $umail);
           $stmt->bindparam(":upass", $new_password);            
           $stmt->execute(); 

           return $stmt; 
       }
       catch(PDOException $e)
       {
           echo $e->getMessage();
       }    
    }

    public function login($uname,$umail,$upass)
    {
       try
       {
          $stmt = $this->db->prepare("SELECT * FROM users WHERE user_name=:uname OR user_email=:umail LIMIT 1");
          $stmt->execute(array(':uname'=>$uname, ':umail'=>$umail));
          $userRow=$stmt->fetch(PDO::FETCH_ASSOC);
          if($stmt->rowCount() > 0)
          {
             if(password_verify($upass, $userRow['user_pass']))
             {
                $_SESSION['user_session'] = $userRow['user_id'];
                return true;
             }
             else
             {
                return false;
             }
          }
       }
       catch(PDOException $e)
       {
           echo $e->getMessage();
       }
   }

   public function is_loggedin()
   {
      if(isset($_SESSION['user_session']))
      {
         return true;
      }
   }

   public function redirect($url)
   {
       header("Location: $url");
   }

  public function logout()
  {
      session_destroy();
      $_SESSION['user_session'] = true;
  }
}
?>

It would be nice if someone could help!

Answer 1

In class.user.php you have a:

function __construct($DB_con)
{
  $this->db = $DB_con;
}

and when you use it in logout.php:

$user = new USER();

You have to pass the $DB_con to __constructor, or create a __constructor that has no arguments, and add another function to initialize the DB:

function __construct()
{
} 
public function initDB($DB_con)
{
  $this->db = $DB_con;
}

and then you can use it like that:

$YourDB = whatever_get_DB();
$user = new USER();
// And when you need:
$user.initDB($YourDB);

or without this only:

$YourDB = whatever_get_DB();
$user = new USER($YourDB);

Answer 2

Your have to pass DB connection to USER constructor.

Answer 3

The thrown error is pretty clear. You are missing an argument in your constructor, expected 1 got 0 arguments.

So, basically when you instantiate a class new ClassName(), the constructor arguments are placed in the brackets.

//               v Arguments of the constructor goes here 
$user = new USER( );

In your case, you are missing the arguments which the class constructor needs, ($DB).