Threaded Networking in Ruby

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Threaded Networking in Ruby

snuxoll — Fri, 10/10/2008 - 21:04

Today in #ruby on Freenode someone who was working on an IRC bot was showing off their code and pointed out that it couldn't maintain more than one connection at a time. While I already had a IRC specific chunk of code I used myself to show him, I figured a more general solution would be a good idea. As such I figured I'd encapsulate a network connection in a simple class, so here you go!

# General purpose wrapper for network connections
class NetworkConnection
  attr_reader :hostname, :port, :thread
  # Creates a new instance of NetworkConnection with the
  # specified hostname and port
  def initialize(hostname, port)
    @hostname = hostname
    @port = port
  end
  # Connects to the specified hostname and port given in new
  def connect
    @thread = Thread.new do
      @socket = TCPSocket.new(@hostname, @port)
      @socket.each { |line|  @block.call(line) }
    end
  end
  # Closes the socket
  def disconnect
    @socket.close
  end
  # Takes a block of code to be called on each line recieved
  def on_recv(&block)
    @block = block
  end
  # Sends text to the socket
  def send(text)
    @socket.send(text + '\r\n', 0)
  end
end

So now, the usual sample usage!

connection = NetworkConnection.new("irc.freenode.net", 6667)
connection.on_recv { |line| puts line }
connection.connect

Obviously this sample code will exit right after the connection is made, since the connection is maintained in a separate ruby thread. I'll leave it up to you to actually find some use in this, but there you go.

GServer

Anonymous — Sat, 10/11/2008 - 02:50

Doesn't Ruby's included GServer library do something similar?

Not that I'm aware of, but

snuxoll — Sat, 10/11/2008 - 03:47

Not that I'm aware of, but this was meant to be a simple way to show how to do threaded networking in ruby apps, so take it for what it's worth.

----
Stefan Nuxoll

rick

Anonymous — Sat, 10/11/2008 - 11:26

what is @thread's initial value? It's not mentioned anywhere else in the class.

@thread isn't made until

snuxoll — Sat, 10/11/2008 - 11:50

@thread isn't made until NetworkConnection#connect is called, and when it is created it's the instance of the worker thread that listens to the socket for incoming data.

Edit: Aaah, I see why you asked that, I made a mistake in my code.