gistfile1.rb

module AVCacheTTL
  def self.included(base)
    base.alias_method_chain :cache, :ttl
  end

  def cache_with_ttl(name = {}, options = nil, &block)
    options = (options || {}).dup
    return block.call if options.delete(:ignore_cache)
    time = options.delete(:ttl)
    time = time.from_now if time.respond_to?(:from_now)
    cache_store = controller.cache_store
    key         = controller.fragment_cache_key(name)
    expiry_key  = "expiry/#{key}"
    cached_time = cache_store.read(expiry_key, options)
    if !cached_time || Time.at(cached_time.to_i).utc <= Time.now.utc
      cache_store.delete(key, options)
      cache_store.write(expiry_key, time.to_i.to_s, options)
    end
    cache_without_ttl(name, options, &block)
  end
end

ActionView::Helpers::CacheHelper.send(:include, AVCacheTTL)