Question

I’m tinkering with golang and my first code is a simple IRC bot with the following code:

package main

import ("net"
        "log"
        "bufio"
        "fmt"
        "net/textproto"
      )
type Bot struct{
        server string
        port string
        nick string
        user string
        channel string
        pass string
        pread, pwrite chan string
        conn net.Conn
}

func NewBot() *Bot {
        return &Bot{server: "irc.freenode.net",
                    port: "6667",
                    nick: "subsaharan",
                    channel: "#rapidsms", 
                    pass: "",
                    conn: nil,
                    user: "blaze"}
}
func (bot *Bot) Connect() (conn net.Conn, err error){
  conn, err = net.Dial("tcp",bot.server + ":" + bot.port)
  if err != nil{
    log.Fatal("unable to connect to IRC server ", err)
  }
  bot.conn = conn
  log.Printf("Connected to IRC server %s (%s)\n", bot.server, bot.conn.RemoteAddr())
  return bot.conn, nil
}



func main(){
  ircbot := NewBot()
  conn, _ := ircbot.Connect()
  conn.Write([]byte("NICK " + ircbot.nick))
  conn.Write([]byte("JOIN " + ircbot.channel))
  defer conn.Close()

  reader := bufio.NewReader(conn)
  tp := textproto.NewReader( reader )
  for {
        line, err := tp.ReadLine()
        if err != nil {
            break // break loop on errors    
        }
        fmt.Printf("%s\n", line)
    }

}

When I run this code I get the following output on the terminal:

2012/11/12 13:31:20 Connected to IRC server irc.freenode.net (193.219.128.49:6667)
:sendak.freenode.net NOTICE * :*** Looking up your hostname...
:sendak.freenode.net NOTICE * :*** Checking Ident
:sendak.freenode.net NOTICE * :*** Couldn't look up your hostname
:sendak.freenode.net NOTICE * :*** No Ident response
ERROR :Closing Link: 127.0.0.1 (Connection timed out)

Any reason why the connection keeps timing out?

Answer 1

All commands sent to an IRC server have a maximum of 255 512 bytes and must be terminated with a carriage return and linefeed \r\n.

conn.Write([]byte("NICK " + ircbot.nick + "\r\n"))
conn.Write([]byte("JOIN " + ircbot.channel + "\r\n"))

Additionally, freenode expects the USER command to be first thing it sees from you.

conn.Write([]byte("USER "+ircbot.nick+" 8 * :" + ircbot.nick + "\r\n"))
conn.Write([]byte("NICK " + ircbot.nick + "\r\n"))
conn.Write([]byte("JOIN " + ircbot.channel + "\r\n"))

As a side note, you can make your life a little easier by using fmt.Fprintf to format and send the data:

fmt.Fprintf(conn, "USER %s 8 * :%s\r\n", ircbot.nick, ircbot.nick)
fmt.Fprintf(conn, "NICK %s\r\n", ircbot.nick)
fmt.Fprintf(conn, "JOIN %s\r\n", ircbot.channel)

The first parameter of fmt.Fprintf must be any type that satisfies the io.Writer interface. The net.Conn implementations all do this. As such you can pass them into any function which expects an io.Writer (or io.Reader for that matter) implementation.