1.rb

class Game < ActiveRecord::Base
  belongs_to :category
  validates_presence_of :title, :category_id, :description,
                        :price, :platform, :year

  def get_official_price
    open("http://thegamedatabase.com/api/game/#{name}/price?api_key=ek2o1je")
  end

  def print
    <<-EOF
      #{name}, #{platform}, #{year}

      current value is #{get_official_price}
    EOF
  end
end

2.rb

class Game < ActiveRecord::Base
  belongs_to :category
  validates_presence_of :title, :category_id, :description,
                        :price, :platform, :year
end

class GamePriceService
  attr_accessor :game

  BASE_URL = "http://thegamedatabase.com/api/game"
  API_KEY = "ek2o1je"

  def initialize(game)
    self.game = game
  end

  def get_price
    data = open("#{BASE_URL}/#{game.name}/price?api_key=#{API_KEY}")
    JsonParserLib.parse(data)
  end
end

class GamePresenter
  attr_accessor :game

  def initialize(game)
    self.game = game
  end

  def print
    price_service = GamePriceService.new(game)
    <<-EOF
      #{game.name}, #{game.platform}, #{game.year}

      current value is #{price_service.get_price[:value]}
    EOF
  end
end

3.rb

class Game < ActiveRecord::Base
  belongs_to :category
  validates_presence_of :title, :category_id, :description,
                        :price, :platform, :year

  def price
    price = read_attribute(:price)
    unless price.present?
      update_attribute(:price, GamePriceService.new(self).get_price)
      read_attribute(:price)
    end
  end
end