Laravel会话无法正常工作

I need to increase the value of the variable when i click on a button but the the value is always one. i had clicked the button to more than five times but still the result is always 1.please see the attached image.

my cart class

class Cart
{
    public $totalQuantity = 0;


    public function __construct($oldCart)
    {
        if ($oldCart) {

            $this->totalQuantity = $oldCart->totalQuantity;
        }

    }

    public function add()
    {
        $this->totalQuantity++;

    }
}

controller method

public function getAddToCart(Request $request,$id){
    $oldCart=null;
    //code that i added now to check which returns null
     dd($request->session()->get('cart'));

    if($request->session()->pull('cart')) {
        $oldCart=$request->session()->pull('cart') ;
    }

    $cart=new Cart($oldCart);
    $cart->add();

    $request->session()->push('cart',$cart);
    dd($request->session()->pull('cart'));

    return redirect()->back();
}

following is the image

Laravel doc:

The pull method will retrieve and delete an item from the session in a single statement

So if you pull it in the if statetment than the second pull has nothing to offer you as you already deleted it :). You should use get instead, or pull it directly in the $oldCart variable.

Oh and also if you use push method it is stored as an array so your code should look like this:

$oldCart = $request->session()->pull('cart');

if ($oldCart) {
    $cart = new Cart($oldCart[0]);
} else {
    $cart = new Cart(null);
}
$cart->add();

$request->session()->push('cart',$cart);

or even better like this:

$oldCart = null;

if ($request->session()->has('cart')) {
    $oldCart = $request->session()->get('cart');
}

$cart = new Cart($oldCart);
$cart->add();

$request->session()->put('cart',$cart);