Remove items from cart and add this quantity back to the stock_quantity (rubyonrails)

i am trying to build a shop, but i have an error after removing my items from cart, while try to add the cart.items.quantity back to the product.stock_quantity. This are the error messages:

NoMethodError in CartsController#remove
undefined method `quantity' for {"product_id"=>"1", "quantity"=>21}:Hash

.

Routing Error
No route matches [GET] "/cart/destroy/1"

Here is the important part of my carts_controller:

    def remove
    cart = session['cart']
    item = cart['items'].find { |item| item['product_id'] == params[:id] }

    product = Product.find(item['product_id'])

    product.update_columns(stock_quantity: product.stock_quantity + item.quantity)

    if item
        cart['items'].delete item
    end
  redirect_to cart_path
end

If i change the item.quantity to just +1 , everything works fine. But i actually want to add the hole cart.item.quantity back to the stock_quantity. Here is the routes file:

Rails.application.routes.draw do
resources :stockists
post 'emaillist/subscribe' => 'emaillist#subscribe'
get 'products/search' => 'products#search', as: 'search_products'
get 'pages/index'
get 'pages/about'
get 'pages/help'
devise_for :users
resources :categories
resources :categories
resources :designers
resources :category_names
resources :products
resource :cart, only: [:show] do
post "add", path: "add/:id", on: :member
delete 'remove', path: 'destroy/:id'
get :checkout
end
resources :orders, only: [ :index, :show, :create, :update ] do
member do
get :new_payment
post :pay
end
end

Does anyone have an idea?

As the error indicates, item is a hash. So, you can't call item.quantity. Try item[:quantity] instead.

If the routing error persists and you are getting the error:

TypeError in CartsController#remove nil can't be coerced into Fixnum

Then try: item['quantity']