# File lib/webrick/httpproxy.rb, line 102
    def proxy_service(req, res)
      # Proxy Authentication
      proxy_auth(req, res)      

      # Create Request-URI to send to the origin server
      uri  = req.request_uri
      path = uri.path.dup
      path << "?" << uri.query if uri.query

      # Choose header fields to transfer
      header = Hash.new
      choose_header(req, header)
      set_via(header)

      # select upstream proxy server
      if proxy = proxy_uri(req, res)
        proxy_host = proxy.host
        proxy_port = proxy.port
        if proxy.userinfo
          credentials = "Basic " + [proxy.userinfo].pack("m*")
          credentials.chomp!
          header['proxy-authorization'] = credentials
        end
      end

      response = nil
      begin
        http = Net::HTTP.new(uri.host, uri.port, proxy_host, proxy_port)
        http.start{
          if @config[:ProxyTimeout]
            ##################################   these issues are 
            http.open_timeout = 30   # secs  #   necessary (maybe bacause
            http.read_timeout = 60   # secs  #   Ruby's bug, but why?)
            ##################################
          end
          case req.request_method
          when "GET"  then response = http.get(path, header)
          when "POST" then response = http.post(path, req.body || "", header)
          when "HEAD" then response = http.head(path, header)
          else
            raise HTTPStatus::MethodNotAllowed,
              "unsupported method `#{req.request_method}'."
          end
        }
      rescue => err
        logger.debug("#{err.class}: #{err.message}")
        raise HTTPStatus::ServiceUnavailable, err.message
      end
  
      # Persistent connction requirements are mysterious for me.
      # So I will close the connection in every response.
      res['proxy-connection'] = "close"
      res['connection'] = "close"

      # Convert Net::HTTP::HTTPResponse to WEBrick::HTTPProxy
      res.status = response.code.to_i
      choose_header(response, res)
      set_cookie(response, res)
      set_via(res)
      res.body = response.body

      # Process contents
      if handler = @config[:ProxyContentHandler]
        handler.call(req, res)
      end
    end