checkout_controller.rb

require 'httparty'

Spree::CheckoutController.class_eval do
  include Spree::Adyen::CheckoutRescue

  Spree::Payment.send :attr_accessor, :request_env
  Spree::PermittedAttributes.payment_attributes.push request_env: ['HTTP_USER_AGENT', 'HTTP_ACCEPT']
  Spree::PermittedAttributes.source_attributes.push :customer_enabled

  before_filter :set_payment_request_env, only: :update

  before_filter :allow_adyen_origin

  private
    def set_payment_request_env
      if params[:order] && params[:order][:payments_attributes]
        params[:order][:payments_attributes].first[:request_env] = request.headers.env
      end
    end

    def allow_adyen_origin
      if @order.payment? && params[:state] == "payment"
        payment_method = @order.available_payment_methods.last

        redirect_params = {
              :currency_code => Spree::Config.currency,
              :ship_before_date => Date.tomorrow,
              :session_validity => 10.minutes.from_now,
              :recurring => false,
              :merchant_reference => "#{@order.number}",
              :merchant_account => payment_method.preferred_merchant_account,
              :skin_code => payment_method.preferred_skin_code,
              :shared_secret => payment_method.preferred_shared_secret,
              :payment_amount => (@order.total.to_f * 100).to_int
        }

        methods = HTTParty.get ::Adyen::Form.payment_methods_url(redirect_params.merge(countryCode: "US"))
        @hpp_payment_methods = methods.is_a?(Hash) ? methods["paymentMethods"] || {} : {}
      end
    end
end