Building an IRC bot in Ruby from scratch

Tamás Michelberger

Secret Sauce Partners, Inc.

Internet Relay Chat

• It's been with us since forever (actually 1988)
• Text-based chat protocol
• Client-server
• Mostly standardized (RFC-1459, RFC-2812)

Anatomy of a message

:tmichel!~tmichel@example.com PRIVMSG
##budapestrb :some message\r\n

What do we actually need to run a bot?

1. Open a TCP connection to an IRC server
2. Register a user (NICK + USER)
3. Wait for incoming messages

Let's build one

Using sockets in RUby

require "socket"

sock = TCPSocket.new(host, port)
while message = sock.gets
    puts message
end
sock.close

TCPSocket is an IO like object

• gets

• read

• read_nonblock
  + IO.select
  

• read*

Timeout is evil

Timeout.timeout(5) do
    # Do something with a socket
    # and now you have a race condition 
    # on your hands
end

More: Timeout: Ruby's Most Dangerous API

Thanks!

Questions?

We are hiring!

sspinc.workable.com

REferences

• A quick, basic guide on the IRC protocol
• RFC-2812
• Timeout: Ruby's Most Dangerous API
• Socket Timeouts in Ruby

• Setting a Socket Connection Timeout in Ruby