variable won't change in PHP class

Question

The method -- initially called in index.php -- redirects to another page. The problem here is that variable $logged_in isn't getting assigned a new value... which means that when the variable is used in the other page, it is read as false.

NOTE: The assignment of session 'id' and session 'type' is correct.

class Session {    
    public $logged_in = false;
    public function login($data) {
        if ($data) {
            $_SESSION['id'] = $data['id'];
            $_SESSION['type'] = $data['type'];
            $this->logged_in = true;            
        }
    }
 }

Answer 1

This is a class and therefore is lost (its properties are lost) at the end of the first scripts execution and then recreated in the second in its initial state.

Classes do not live across executions of the same script or any other script.

If you wish to maintain the objects state, you will have to save the state to a file or maybe the real SESSION so you can re-hydrate the data when the second script starts

session_start();

class Session {    

    public function login($data) {
        if ($data) {
            $_SESSION['id'] = $data['id'];
            $_SESSION['type'] = $data['type'];
            $_SESSION['logged_in'] = true;            
        }
    }

    // getter function
    public function is_logged_in()
    {
        // just in case check
        if ( isset($_SESSION['logged_in']) ) {
            return $_SESSION['logged_in'] == true;
        } else {
            return false;
        }
    }
}

Called like this

$s = new Session();
if ( ! $s->is_logged_in() ) {
    header('Location: index.php');
    exit;
}

To keep it away from the SESSION completely you could

class Session {
    public $id;
    public $type;
    public $logged_in;


    public function __construct()
    {
        if ( file_exists('my_session.txt')) {
            $obj = json_decode(file_get_contents('my_session.txt'));
            foreach($obj as $prop => $val) {
                $this->{$prop} = $val;
            }
        }
    }

    public function __destruct()
    {
        file_put_contents('my_session.txt', json_encode($this));
    }

    public function login($data) {
        if ($data) {
            $this->id           = $data['id'];
            $this->type         = $data['type'];
            $this->logged_in    = true;
        }
    }
}


$obj = new Session();
$obj->login(array('id'=>99, 'type'=>'TEST'));

print_r($obj);

$obj = null;

echo 'object nulled' . PHP_EOL;
print_r($obj);
echo ' NOTHING should be printed' . PHP_EOL;

echo 'object rehydrated' . PHP_EOL;
$obj = new Session();
print_r($obj);

Answer 2

create another method check_login() to re-assign the values in the new page and call it within __construct()

function __construct(){
    $this->check_login();
}
public function check_login(){
    if(isset($_SESSION['id']) && isset($_SESSION['type']){
        $this->logged_in = true;
    } else {
        $this->logged_in = false;
    }
}