gistfile1.rb

require 'rubygems'
require 'eventmachine'

module ChatClient
  def self.list
    @list ||= []
  end

  def post_init
    @name = "anonymous_#{rand(99999)}"
    ChatClient.list.each{ |c| c.send_data "#{@name} has joined.\n" }
    ChatClient.list << self
  end
  def unbind
    ChatClient.list.delete self
    ChatClient.list.each{ |c| c.send_data "#{@name} has left.\n" }
  end

  def receive_data data
    (@buf ||= '') << data
    while line = @buf.slice!(/(.+)\r?\n/)
      if line =~ %r|^/nick (.+)|
        new_name = $1.strip
        (ChatClient.list - [self]).each{ |c| c.send_data "#{@name} is now known as #{new_name}\n" }
        @name = new_name
      elsif line =~ %r|^/quit|
        close_connection
      else
        (ChatClient.list - [self]).each{ |c| c.send_data "#{@name}: #{line}" }
      end
    end
  end
end

EM.run{
  EM.start_server '0.0.0.0', 8081, ChatClient
}