Cahce

Cache.rb

class Cache2
    def initialize(opts={})
      options = {:expiration => 24*60*60}.merge!(opts)
      @exp = options[:expiration]
    end
    def [](index)
      if @cache[index].expired? then @cache[index].refresh end
      @cache[index].contents
    end
    def add(index, expires=nil, &block)
      @cache = {}
      @cache[index] = Item.new expires || @exp, index, &block
    end
    class Item
      attr_accessor :contents 
      def initialize(expiration, index, &block)
        @index = index
        @exp = expiration
        @refreshBlock = block
      end
      def refresh 
        @contents = @refreshBlock.call @index
        @modified = Time.now
      end
      def expired?
        if (Time.now <=> (@modified + @exp)) == -1 then  false  else true end
      end
    end
  end

Usage.rb

cache = Cache2.new({:expiration=>2*60})
cache.add(:tweet) do
  Twitter.user_timeline("gdotdesign").first
end
cache.add(:timeline, 2*60*60) do
  Twitter.user_timeline("gdotdesign")
end
# now you can use it whereever you like
# and it fetches every two minutes
puts cache[:tweet].text