stream from http source to client with Goliath

dropbox.rb

require 'goliath'
require 'json'
require "em-synchrony"
require "em-synchrony/em-http"

class GetImage < Goliath::API
  def response(env)
    @uri = ('http://dl.dropbox.com/u/3528102/10.iso') #10mb file
    
    EM.next_tick do
      http = EventMachine::HttpRequest.new(@uri).aget  
      finish = proc { env.chunked_stream_close }
      
      http.stream { |chunk| env.chunked_stream_send chunk }
      http.callback &finish
      http.errback &finish
    end
    

    headers = {'Content-Type' => 'application/octet-stream',
               'X-Stream'     => 'Goliath'}

    chunked_streaming_response(200, headers)
  end
  
  def on_close(env)
    env.logger.info "Connection closed"
  end
end

class Server < Goliath::API
  # use Goliath::Rack::Params
  get '/image', GetImage
end