滑轨。 在保存孩子之前先保存父母

Question

When I try create line_item, I get this error: ActiveRecord::RecordNotSaved (You cannot call create unless the parent is saved).

When I wrong? How fix it?

line_items controller

def create
  @product = Product.find_by_id(params[:line_item][:product_id])
  @cart = current_cart
  @line_item = @cart.add_product(line_item_params)
end

cart model

has_many   :line_items, dependent: :destroy

def add_product(line_item_args)
    current_line_item.quantity += line_item_args[:quantity].to_i
    current_line_item.save

  if current_item
    current_item.quantity += line_item.quantity.to_i
  else
    current_item = line_items.create!(line_item_args)
  end
  current_item
end

UPD

working helper method current_cart from application controller. problem was in it.

def current_cart
    Cart.find(session[:cart_id])
rescue ActiveRecord::RecordNotFound
    cart = Cart.create
    session[:cart_id] = cart.id
    cart
end

Answer 1

我不知道您如何使用购物车，但是我确定当前的购物车未在数据库中保存，请检查其是否正确。