NoMethodError in OrdersController#create

Question

I'm building a simple shopping application and trying to use Ryan Bates's "#145 Integrating Active Merchant" for guidance to build the checkout process.

Order model:

class Order < ActiveRecord::Base

has_many :order_products
has_many :products, through: :order_products

attr_accessor :card_number, :security_code, :card_expires_on


def credit_card

    @credit_card ||= ActiveMerchant::Billing::CreditCard.new(
        :first_name             => first_name,
        :last_name              => last_name,
        :card_number            => card_number,
        :verification_value     => security_code,
        :month                  => card_expires_on{month},
        :year                   => card_expires_on{year}
        )
end


def self.purchase(basket)

    response = GATEWAY.purchase(Product.total_basket_price(basket), credit_card)

end




end

Orders_controller:

    def create
    
    @order = Order.new

    basket.each do |item_id|
        @order.order_products.build(product: Product.find(item_id))
    end

    if @order.save!
        if @order.purchase
            render "show"
        else
            render "new"
        end
    else
        render "new"
    end

end

Product model:

  def self.total_basket_price(basket)
    where(id: basket.to_a).sum(:price)*100
  end

When i click submit, i receive the following error message:

NoMethodError in OrdersController#create

undefined method `purchase'

Answer 1

purchase is a class record, but you try to call it on the instance of Order. Also, this method requires an argument, but you try to call it without them.