base.rb

class Calculator::FedEx::Base < Calculator::ActiveShipping
  def carrier
    ActiveMerchant::Shipping::FedEx.new(:key =>Spree::ActiveShipping::Config[:fedex_api_key],
                                        :password =>Spree::ActiveShipping::Config[:fedex_api_password],
                                        :account => Spree::ActiveShipping::Config[:fedex_account_number],
                                        :login => Spree::ActiveShipping::Config[:fedex_meter_number])
  end

  def to_s
    super.gsub("Fed Ex", "FedEx")
  end

  private

  def retrieve_rates(origin, destination, packages)
    begin
      response = carrier.find_rates(origin, destination, packages, :test => Spree::ActiveShipping::Config[:fedex_test])
      # turn this beastly array into a nice little hash
      Hash[*response.rates.collect { |rate| [rate.service_name, rate.price] }.flatten]
    rescue ActiveMerchant::Shipping::ResponseError => re     
      msg = "#{I18n.t('shipping_error')}: #{re.message}"
      raise Spree::ShippingError.new(msg)
    end
  end

end