shipping.rb

require 'yaml'

file_data = YAML.load_file('shipping.yaml')

class ShippingData

  def initialize(attr={})
    @sd_data = attr
  end

  def sd_data
    @sd_data
  end

  def method_missing(method_name, arg= nil)

    method_name = arg unless arg.nil?

    if @sd_data.respond_to?(method_name)
      new_sd = ShippingData.new(@sd_data.send(method_name))
    else
      new_sd = ShippingData.new(@sd_data[method_name.to_s])
    end

    puts new_sd.sd_data if new_sd.sd_data.class == String
    return new_sd
  end
end

data = ShippingData.new(file_data)

data.product.first.sku

data["product"].first["sku"]