A simple IRC bot written in Go.

irc.go

package main

import (
	"fmt"
	"net/textproto"
	"regexp"
)

var (
	conn *textproto.Conn
	err error
	privmsg = regexp.MustCompile("^:([a-zA-Z0-9`_\\-]+)![a-zA-Z0-9/\\\\\\.\\-]+@[a-zA-Z0-9/\\\\\\.\\-]+ PRIVMSG (#[a-zA-Z0-9]+) :(.*)$")
	ping    = regexp.MustCompile("^PING :([a-zA-Z0-9\\.]+)$")
	motd    = regexp.MustCompile(":End of /MOTD command\\.$")
)

type PrivMsg struct {
	nick string
	channel string
	message string
}

type Bot struct {
	nick string
	channel string
	host string
	port string
}

func (bot Bot) sendMessage(channel, message string){
	conn.Cmd("PRIVMSG %s :%s\r\n", channel, message)
}

func (bot Bot) parseLine(line string){
	if match := privmsg.FindStringSubmatch(line); match != nil {
		pm := new(PrivMsg)
		pm.nick, pm.channel, pm.message = match[1], match[2], match[3]
		bot.messageHandler(*pm)
	}

	if match := ping.FindStringSubmatch(line); match != nil {
		conn.Cmd("PONG :%s\r\n", match[1])
	}

	if match := motd.FindStringSubmatch(line); match != nil {
		conn.Cmd("JOIN %s\r\n", bot.channel)
	}
}

func (bot Bot) messageHandler(pm PrivMsg){
	fmt.Printf("%s: %s\n", pm.nick, pm.message)
}

func (bot Bot) start(){
	conn, err = textproto.Dial("tcp", bot.host + ":" + bot.port)
	if err != nil {
		fmt.Printf("%s", err)
	}
	conn.Cmd("NICK %s\r\n", bot.nick)
	conn.Cmd("USER %s 8 * :%s", bot.nick, bot.nick)
	for {
		text, err := conn.ReadLine()
		if err != nil {
			fmt.Print("%s", err)
			return 
		}
		go bot.parseLine(text)
	}
}

func main() {

	bot := new(Bot)
	bot.nick = "Jaybot"
	bot.channel = "#test"
	bot.host = "irc.unixhub.net"
	bot.port = "6667"
	bot.start()
}