From: Leslie Viljoen <leslieviljoen@...>
Date: 2008-06-11T07:39:32+09:00
Subject: Re: Non blocking UDP

On Wed, Jun 11, 2008 at 12:16 AM, Joel VanderWerf
<vjoel@path.berkeley.edu> wrote:
> Leslie Viljoen wrote:
>>
>> Hello!
>>
>> I need to make a UDP server that waits for clients to log on and then
>> drives
>> communication from the server side. This means that if a client doesn't
>> ack
>> subsequent comms from the server, the server needs to resend those
>> comms a few times before giving up.
>>
>> I have gotten as far as a successful UDP server, but it blocks the thread
>> forever, and having a server constantly breaking out of
>> socket.recvfrom using Timeout
>> does not seem to work at all (port never seems open). I need a UDP wait
>> with a timeout.
>>
>> I have looked at several UDP examples, and tried the sparse docs here:
>> http://ruby-doc.org/stdlib/libdoc/socket/rdoc/classes/Socket.html#M004528
>>
>> - but no luck yet. I tried recvfrom_nonblock as a guess but it seems to
>> block anyway.
>>
>> Any tips?
>>
>> Les
>
> IO#select ?

Below is my guess that doesn't work - I get connection refused when
trying to connect to the port.

Is there any proper documentation for these esoteric methods?
http://www.ruby-doc.org/core/classes/Kernel.html#M001109 doesn't help,
and even the Pickaxe ed. 3 gives not much more clue than what I tried.


#!/usr/bin/ruby -w

require 'socket'

class UdpServer
	def initialize(ip, port)
		socket = UDPSocket.new
		socket.bind(ip, port)

		loop do
			a = IO.select([socket], nil, nil, 5)
			p a
			sleep(1)
		end

	end
end

s = UdpServer.new("0.0.0.0", 7778)