Simple chat server with eventmachine

emchat.rb

#!/usr/bin/env ruby

#
# Chat server attempt with Ruby and EventMachine.
#
# TODO: 
#
# - Prevent chat from acting on \n (pressing enters in chat)
# - Handle (unexpected) disconnects properly (with unbind event).
# - Implement proper leaving with /quit.
# - Force names to be unique.
# - Implements private messages (using the unique names)
# - Handle annoying escape codes and arrow keys etc on prompt better.
#
# - Improvements
# - Funn Stuff
#
# - Implement channels?
# - Make a version for the real IRC protocol?
#
#
# CHANGELOG:
#
# - 21 Mar 2012
#   - Name validation added using regex
#   - Added /me for the purpose of testing regex $1
#   - Added error handling with rescues
#   - Removed @name from sendpublic to have a more general use, and added it in the else case statement
#   - Replaced if elsif elsif else with a case statement using regex when checking for known commands
#
#
# Created on: 20 Mar 2012 01:28
# Updated on: 21 Mar 2012 21:25
#
#
# EvilBetty
#

require 'eventmachine'

# Config
IP = '0.0.0.0'
PORT = 8081


class EmChat  < EventMachine::Connection

  #Accessor for name attribute and initialise the connections array
  attr_accessor :name
  @@clients = []

  #Own functions here

  #Send data provided to all clients except the sending client by looping though all connections in array
  def sendpublic(data)
    @@clients.each do |client|
      begin
        #A bit messy way to remove the > that was already printed before with 2 backspaces, and readd > again after
        client.send_data "\b\b#{data.strip}\n> " unless client == self
      rescue
        #if we cannot send to a client anymore remove it from clients list
        @@clients.delete client
      end
    end
  end

  #EventMachine built in events below

  #When a new connection is made welcome the client and ask name for initialisation
  def post_init
    send_data("Welcome to this chat server.\nWhat is your name? ")
  end

  #When data is received from a client this event runs
  def receive_data(data)
  
    #If name is not yet set do this first,set @initiated to true, and only now add client to connections array
    if !@initiated
      #Make sure name is 3 to 15 chars, and only contains letters and numbers
      if data.strip =~ /^[a-zA-Z0-9]{3,15}$/
        @name = data.strip
        @@clients  << self
        send_data "Welcome #{@name}.\n"
        @initiated = true
        sendpublic "#{@name} has joined.\n > "
      else
        send_data "Invalid Name. Max 15 chars. Only letters or numbers.\nName : "
      end

    #After initialisation of a connection continue here
    else

      #Check for recognised commands and handle them
      case (data.strip)
        
        # /names
        when /^\/names$/ then
          send_data "Current Users: " + @@clients.find_all.collect{ |client| client.name }.sort.join(" ") + "\n > "

        # /help
        when /^\/help$/ then
          send_data "Help not implemented yet\n > "

        # /me text
        when /^\/me (.*)$/ then
          sendpublic "* #{@name} #{$1.strip}"
          send_data "* #{@name} #{$1.strip}\n >"

        #If data is not a recognised command assume its chat text and send to all clients
        else
          sendpublic "#{@name} > #{data}"
          send_data " > "
        end
      end
    end
  end


EM::run do
  begin
    EM::start_server IP, PORT, EmChat
    puts "Service started on #{IP}:#{PORT}."
  rescue RuntimeError
    puts "Failed to start service on #{IP}:#{PORT}"
    exit 1
  end
end