Tiny IRC bot in Go, just to get started with the language

tinybot.go

// written by Daniel Oaks <daniel@danieloaks.net>
// released under the CC0 Public Domain license

package main

import (
	"fmt"
	"os"
	"strings"

	"github.com/docopt/docopt-go"
	"github.com/goshuirc/eventmgr"
	"github.com/goshuirc/irc-go/client"
	"github.com/goshuirc/irc-go/ircfmt"
	"github.com/goshuirc/irc-go/ircmap"
)

// rawHandler prints raw messages to and from the server.
func rawHandler(event string, info eventmgr.InfoMap) {
	sc := info["server"].(*gircclient.ServerConnection)
	direction := info["direction"].(string)
	line := info["data"].(string)

	var arrow string
	if direction == "in" {
		arrow = "<- "
	} else {
		arrow = " ->"
	}

	fmt.Println(sc.Name, arrow, ircfmt.Escape(strings.Trim(line, "\r\n")))
}

// eventHandler prints actual events to and from the server.
func eventHandler(event string, info eventmgr.InfoMap) {
	sc := info["server"].(*gircclient.ServerConnection)
	direction := info["direction"].(string)

	var arrow string
	if direction == "in" {
		arrow = "<- "
	} else {
		arrow = " ->"
	}

	fmt.Println(sc.Name, arrow, info["tags"], info["prefix"], info["command"], info["params"])
}

// privmsgHandler handles incoming PRIVMSGs.
func privmsgHandler(event string, info eventmgr.InfoMap) {
	sc := info["server"].(*gircclient.ServerConnection)
	target, _ := ircmap.Casefold(sc.Casemapping, info["params"].([]string)[0])
	fmt.Println(sc.Name, target, "<", info["prefix"].(string), ">", ircfmt.Escape(info["params"].([]string)[1]))
}

func main() {
	version := "tinybot 0.0.1"
	usage := `tinybot.

Usage:
	tinybot connect <host> [--ssl] <nick>
	tinybot -h | --help
	tinybot --version

Options:
	<host>     Host to connect to (example: localhost:6667).
	<nick>     Nickname to connect with.
	--ssl      Connect securely using TLS.
	-h --help  Show this screen.
	--version  Show version.`

	arguments, _ := docopt.Parse(usage, nil, true, version, false)

	if arguments["connect"].(bool) {
		fmt.Println("Connecting to", arguments["<host>"], "as", arguments["<nick>"])

		// create reactor and server
		reactor := gircclient.NewReactor()
		server := reactor.CreateServer("test")

		// set info
		server.InitialNick = arguments["<nick>"].(string)
		server.InitialUser = server.InitialNick

		// attach events
		server.RegisterEvent("in", "PRIVMSG", privmsgHandler, 0)
		server.RegisterEvent("in", "raw", rawHandler, 0)
		server.RegisterEvent("out", "raw", rawHandler, 0)
		// server.RegisterEvent("in", "all", eventHandler, 0)
		// server.RegisterEvent("out", "all", eventHandler, 0)

		// actually connect
		err := server.Connect(arguments["<host>"].(string), arguments["--ssl"].(bool), nil)

		if err != nil {
			fmt.Println("Connection error:", err)
			os.Exit(1)
		}

		server.ReceiveLoop()
	}
}