IRC proxy/download throttler combo script

gistfile1.rb

require 'gserver'
require 'timeout'
require 'thread'

class ForwardThread < Thread
  MAX_DATA = 1000 * 1024
  TIME_SLOT = 0.3
  @@lock = Mutex.new
  @@data_sent = 0

  Thread.new do
    while true
      @@lock.lock
      @@data_sent = 0
      @@lock.unlock
      sleep TIME_SLOT
    end
  end

  def report_data(bytes)
    @@lock.lock
    @@data_sent += bytes
    @@lock.unlock
  end

  def can_send?
    @@lock.lock
    r = @@data_sent < MAX_DATA * TIME_SLOT
    @@lock.unlock
    return r
  end

  def initialize(input, output)
    super() do
      until input.eof?
        if can_send?
          #puts "accepted"
          data = input.readpartial(2048)
          report_data(data.size)
          output.print(data)
        else
          #puts "rejected"
          sleep TIME_SLOT/5
        end
      end
      output.close
    end
  end
end

class Limiter < GServer
  def initialize(port=443, host='0.0.0.0')
    super(port, host, Float::MAX, $stderr, true)
  end

  def serve(inside)
    begin
      outside = TCPSocket.new('irc.freenode.net', 6667)
    rescue e
      puts "Error while connecting: " + e.to_s
    else
      puts "Connected!"
      in_to_out = ForwardThread.new(inside, outside);
      out_to_in = ForwardThread.new(outside, inside);
      in_to_out.join
      out_to_in.join
      puts "Stream ended"
    ensure
      outside.close
    end
  end
end

server = Limiter.new(ARGV[0] || 443)
server.start(-1)
server.join