irc.rb

#!/usr/local/bin/ruby

require "socket"

# Don't allow use of "tainted" data by potentially dangerous operations
$SAFE=1

# The irc class, which talks to the server and holds the main event loop
class IRC
  def initialize(server, port, nick, channel)
    @server = server
    @port = port
    @nick = nick
    @channel = channel
  end
  
  def send(s)
    # Send a message to the irc server and print it to the screen
    puts "--> #{s}"
    @irc.send "#{s}\n", 0 
  end
  
  def connect()
    # Connect to the IRC server
    @irc = TCPSocket.open(@server, @port)
    send "USER blah blah blah :blah blah"
    send "NICK #{@nick}"
    send "JOIN #{@channel}"
  end
  
  def evaluate(s)
    # Make sure we have a valid expression (for security reasons), and
    # evaluate it if we do, otherwise return an error message
    if s =~ /^[-+*\/\d\s\eE.()]*$/ then
        begin
            s.untaint
            return eval(s).to_s
        rescue Exception => detail
            puts detail.message()
        end
    end
    return "Error"
  end
  
  def handle_server_input(s)
    # This isn't at all efficient, but it shows what we can do with Ruby
    # (Dave Thomas calls this construct "a multiway if on steroids")
    case s.strip
      when /^PING :(.+)$/i
        puts "[ Server ping ]"
        send "PONG :#{$1}"
      when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s.+\s:[\001]PING (.+)[\001]$/i
        puts "[ CTCP PING from #{$1}!#{$2}@#{$3} ]"
        send "NOTICE #{$1} :\001PING #{$4}\001"
      when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s.+\s:[\001]VERSION[\001]$/i
        puts "[ CTCP VERSION from #{$1}!#{$2}@#{$3} ]"
        send "NOTICE #{$1} :\001VERSION Ruby-irc v0.042\001"
      # when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s(.+)\s:EVAL (.+)$/i
      #   puts "[ EVAL #{$5} from #{$1}!#{$2}@#{$3} ]"
      #   send "PRIVMSG #{(($4==@nick)?$1:$4)} :#{evaluate($5)}"
      when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s(.+)\s:(.*)insult(.*)$/i
        send "PRIVMSG #{(($4==@nick)?$1:$4)} :#{$insult.generate}"
      else
        puts s
    end
  end
  
  def main_loop()
    # Just keep on truckin' until we disconnect
    while true
      ready = select([@irc, $stdin], nil, nil, nil)
      next if !ready
      for s in ready[0]
        if s == $stdin then
          return if $stdin.eof
          s = $stdin.gets
          send s
        elsif s == @irc then
          return if @irc.eof
          s = @irc.gets
          handle_server_input(s)
        end
      end
    end
  end
end