UDP.rb

First step for my TFTP app is to build a simple UDP class.

UDP is a connectionless datagram protocol. You can bundle up some data, send it off to a target machine, and forget about the whole thing. It might not even make it to the destination; nobody cares. This has led the masses to assume that UDP is Unreliable. Consider, however, that UNIX uses UDP for internal messaging protocols. Also consider that, with just a small amount of effort, one can make lock-step communications with ACKing. This is how most networked games push their data around -- TCP would be unacceptable; it's a resource hog. And I always prefer to conserve my resources.

require "socket"

class UDP

   def send( msg, host, port, flags=0 )
      sock = UDPSocket.new
      sock.send( msg, flags, host, port )
      sock.close
   end

   def recv( port, maxblocksize )
      sock = UDPSocket.new
      sock.bind( "localhost", port )
      msg = sock.recv( maxblocksize )
      p sock.addr
      sock.close
      return msg
   end
end

Two methods: send() and recv(). How much simpler can you get? I think the lack of a "connection" is a strength of UDP: the thing is just bare bones. I love that.

Here's some quick-and-dirty test code:

client = UDP.new
client.send( msg, server_addr, server_port )

server = UDP.new

loop do
   msg = server.recv( server_port, maxbytes )
   p msg
   exit if msg.chomp.eql?( 'exit' )
   sleep 1
end