gistfile1.rb

# create a worldpay response object that acts like a string but has the each_header method
# so that we can access the headers that worldpay returns

class WorldPayResponse < String
  
  def initialize(resp)
    @resp = resp
    super(resp.body)
  end
  
  def each_header(&block)
    @resp.each_header &block
  end
  
end

# overwrite the handle_response method so that it returns a WorldPayResponse object rather
# than the response.body string, this acts the same as a string but includes the each_header
# method for accessing the returned headers

module ActiveMerchant
  class Connection
    private
    def handle_response(response)
      case response.code.to_i
      when 200...300
        WorldPayResponse.new(response)
      else
        raise ResponseError.new(response)
      end
    end
  end
end