Rails 购物车添加商品功能实现代码

def add\n user = current_user\n sku_id = params[:sku_id]\n amount = params[:amount].to_i\n\n # 从数据库中查询该商品是否已经在购物车中\n if cart = user.cart_items.find_by(product_sku_id: sku_id)\n\n # 如果存在则直接叠加商品数量\n cart.update(amount: cart.amount + amount)\n else\n\n # 否则创建一个新的购物车记录\n cart = CartItem.new(amount: amount)\n cart.user = user\n cart.product_sku_id = sku_id\n cart.save\n end\n\n render json: {}\nend