ruby実装の非同期ファイルダウンロードHttpServerインスタンス

1.ruby eventmachineとem-http-server gemを使用して、ファイルダウンロード機能を簡単に提供するHttpServerを完成する
2.EMのFileStreamerを使用して非同期でファイルを送信し、ファイルを送信するときにヘッダを組み立ててからFileStreamerを呼び出す

require 'rubygems'
require 'eventmachine'
require 'em-http-server'

class HTTPHandler < EM::HttpServer::Server
 attr_accessor :filename, :filesize, :path

 def process_http_request
 #send file async
 if @http_request_method.to_s =~ /GET/ && @http_request_uri.to_s.end_with?(filename)
  send_data "HTTP/1.1 200 OK
"
  send_data "Server: XiaoMi
"
  send_data "Connection: Keep-Alive
"
  send_data "Keep-Alive: timeout=15
"
  send_data "Content-Type: application/octet-stream
"
  send_data "Content-Disposition: filename='#{filename}'
"
  send_data "Content-Length: #{filesize}
"
  send_data "
"

  streamer = EventMachine::FileStreamer.new(self, path)
  streamer.callback {
  # file was sent successfully
  close_connection_after_writing
  }
 else
  response = EM::DelegatedHttpResponse.new(self)
  response.status = 200
  response.content_type 'text/html'
  response.content = "Package HttpServer
usage: wget http://host:port/#{filename}"
  response.send_response
 end
 end

end

EM::run do
 path = '/tmp/aaa.tar.gz'
 EM::start_server("0.0.0.0", 8080, HTTPHandler) do |conn|
 conn.filename = File.basename(path)
 conn.filesize = File.size(path)
 conn.path = path
 end
end