EM Chat Server Demo

gistfile1.builder

require 'rubygems'
require 'eventmachine'
require 'em-http' # gem install em-http-request
require 'yajl'    # gem install yajl-ruby

class String
  def bold
    "\033[1m#{self}\033[0m"
  end
end

module ChatClient
  def post_init
    @buf = ''
    @name = "anonymous_#{ChatClient.client_num+=1}"
    @sid = ChatClient.channel.subscribe do |msg|
      send_msg(msg)
    end

    send_header
    send_prompt

    ChatClient.channel << "#{@name.bold} has joined.\n"
  end

  def unbind
    ChatClient.channel.unsubscribe(@sid)
    ChatClient.channel << "#{@name.bold} has left.\n"
  end

  def receive_data data
    @buf << data
    quit and return if @buf =~ /(\006|\004)/ # ctrl+c or ctrl+d

    while line = @buf.slice!(/(.+)\r?\n/)
      p [@name, line]
      send_prompt

      if line =~ %r|^/nick (.+)|
        new_name = $1.strip[0..12]
        ChatClient.channel << "#{@name.bold} is now known as #{new_name.bold}\n"
        @name = new_name
        send_prompt

      elsif line =~ %r|^/me (.+)|
        ChatClient.channel << "#{@name.bold} #{$1.strip}\n"

      elsif line =~ %r|^/say (.+)|
        send_msg "\033[37mAdding #{$1.strip.bold} to the say queue at position #{ChatClient.say_queue.size+1}\033[0m\n"
        ChatClient.say_queue.push "#{@name} said #{$1.strip}"

      elsif line =~ %r|^/quit|
        quit

      elsif line =~ /^\e/ # ignore escape sequences
        send_prompt

      elsif !line.strip.empty?
        ChatClient.channel << "#{@name.bold}: #{line.gsub(/[^[:print:]]/,'')}\n"
      end
    end
  end

  private

  def send_header
    send_data "\033[2;23r"
    send_data "\033[2J"
    send_data "\033[1H"
    header = "Welcome to the EventMachine Chat Demo (/nick, /me, /say, /quit)".center(80)
    send_data "\033[32m#{header}\033[0m"
  end

  def send_msg msg
    send_data "\0337"
    send_data "\033M"
    send_data "\033[23;1H"
    send_data msg
    send_data "\0338"
  end

  def send_prompt
    send_data "\033[24H"
    send_data "\033[2K"
    send_data "\033[1m"
    send_data @name
    send_data "\033[0m: "
  end

  def quit
    send_data "\033[2J"
    send_data "\033[1;1H"
    header = "Check out http://gist.github.com/329682 for the source to the EM chat server".center(80)
    send_data "\033[32m#{header}\033[0m"
    send_data "\033[r"
    send_data "\033[3;1H"
    close_connection_after_writing
  end

  @client_num = 0
  class << self
    attr_accessor :client_num
  end

  def ChatClient.channel
    @channel ||= EM::Channel.new
  end

  def ChatClient.say_queue
    @say_queue ||= begin
      q = EM::Queue.new

      # pop off items from the queue one at a time, and pass them to `say`
      processor = proc{ |msg|
        ChatClient.channel << "\033[37mSaying: #{msg.bold}\033[0m\n"
        EM.system("say", msg) do |out, status|
          p [:say, msg, status]
          q.pop(&processor)
        end
      }

      # pop off the first item
      q.pop(&processor)

      q
    end
  end
end

class TwitterStream
  def initialize(user, pass, tags, &blk)
    raise ArgumentError, 'block required' unless blk

    http = EM::HttpRequest.new(
     "http://stream.twitter.com/1/statuses/filter.json?track=#{tags.join(',')}"
    ).get(
      :head => {'authorization' => [user, pass]}
    )

    parser = Yajl::Parser.new(:symbolize_keys => true)
    parser.on_parse_complete = blk
    http.stream do |data|
      parser << data
    end
  end
end

EM.run{
  EM.start_server '0.0.0.0', 1337, ChatClient

  EM::PeriodicTimer.new(90) do
    ChatClient.channel << "\033[31mThe time is now #{Time.now}\033[0m\n"
  end

  TwitterStream.new('USERNAME', 'PASSWORD', %w[ railsconf eventmachine ]) do |tweet|
    name, msg = tweet[:user][:screen_name], tweet[:text]
    p [:tweet, name, msg]
    ChatClient.channel << "\033[34;1m@#{name}\033[0m: #{msg}\n"
  end
}