Laravel Crinsane/LaravelShoppingcart associate() doesn't work - laravel

Question

In my Laravel I'm using this shoppingcart .
When I add one product to my shopping cart I want to have associate() with App\Product Model .
This is my code :
public function store(Request $request)
{
// store product information to Cart
Cart::add($request->id, $request->name, 1, $request->price)
->associate('App\Product');
return redirect(route('cart.index'))
->with('success_message', 'محصول با موفقیت به سبد اضافه شد');
}
But when I want to access model $item->model->id in view I get this error :
Trying to get property 'id' of non-object (View: C:\xampp\htdocs\digikala\resources\views\cart.blade.php)
Edit :
my cart view (cart.blade.php) codes :
<table border="1" class="table">
#foreach (Cart::content() as $item)
{{ $item->model->id }}
#endforeach
</table>

Answer 1

Finally i could solve this problem .
Everything was about $request data inside store() method .
Mistakes were in the form of adding product to cart .
I did not post the product ID correctly to the store() method .
If anyone had this problem in the future I hope to test $request first by this code :
public function store(Request $request)
{
return $request;
}

Answer 2

public function store(Request $request)
{
//verify the submitted product
$product = Product::where('slug', $request->input('slug'))->first();
//check if item is available
if($product === null){
return redirect()->route('cart.index')->with('error', 'Unable to add product to cart');
}
else{
Cart::add($product->id, $product->title, 1, $product->price)
->associate('App\Product');
return redirect()->route('cart.index')->with('success', 'Product added to cart');
}
return false;
}