chat_echo.go

package main

import (
  "bufio"
	"io"
	"net"
	"os"
)

func echoLoop(c chan string,broadcast chan string, con net.Conn) {
	
	rw := bufio.NewReadWriter(
		bufio.NewReader(con),
		bufio.NewWriter(io.MultiWriter(con, os.Stdout)))

	exit := make(chan bool)

	go func() {
		for {
			select {
			case v := <-c:
				rw.WriteString(v + "\n")
				rw.Flush()
			case <-exit:
				con.Close()
				return
			}
		}
	}()

	for {
		bline, _, er := rw.ReadLine()

		if er != nil {
			con.Close()
			return
		}

		line := string(bline)

		switch line {
		case "exit":
			exit <- true
			return
		default:
			broadcast <- line
		}
	}
}

func main() {
	broadcast := make(chan string)
	ln, _ := net.Listen("tcp", ":3457")

	clients := []chan string{}

	go func() {
		for {
			msg := <-broadcast
			for _, c := range clients {
				c <- msg
			}
		}
	}()

	for {
		con, _ := ln.Accept()
		c := make(chan string)
		clients = append(clients, c)
		go echoLoop(c, broadcast, con)
	}
}