response caching in camping (See related posts)

Camping.goes :MyCampingApp

module MyCampingApp
  module Controller
    class View < R '/'
      def get
        cache('root') do
          'Expensive operation!'
        end
      end
    end
  end
  
  def flush(id)
    f = File.dirname(__FILE__) + "/cache/#{id}"
    File.delete(f) if File.exists?(f)
  end
  
  def cache(id, timeout = 1.hour)
    f = File.dirname(__FILE__) + "/cache/#{id}"
    
    if File.exists?(f) && (Time.now - File.stat(f).mtime) < timeout
      File.read(f)
    else
      r = yield
      open(f, 'w'){|wr| wr.write(r)}
      r
    end
  end

  def self.create
    cache_dir = File.dirname(__FILE__) + "/cache"
    Dir.mkdir(cache_dir) unless File.directory?(cache_dir)
  end
end