Hello, World

Well, no, it won't be "Hello, World," not strictly speaking anyway. But here's a really small (and useful) program written with EventMachine.

It's an echo server. It creates a TCP listener on port 10000 that accepts connections, and sends back all data received on each connection.

require 'rubygems'
require 'eventmachine'

module Echo
  def receive_data data
    send_data data
  end
end

EM.run {
  EM.start_server "0.0.0.0", 10000, Echo
}