package main

import (   "net"   "fmt"   "strings"   "time")

type Client struct {   C chan string //用户发送数据的通道   Name string //用户名   Addr string //网络地址}

//保存在线用户 cliaddr ======> clientvar onlineMap map[string]Client

var message = make(chan string)

func WriteMsgToClient(cli Client, conn net.Conn)  {   for msg := range cli.C {      //给当前客户端发送信息      conn.Write([]byte(msg + "\n"))   }}

func MakeMsg(cli Client, msg string) (buf string)  {   buf = "[" + cli.Addr + "]" + cli.Name + ": login"   return}

func HandleConn(conn net.Conn)  { //处理用户连接   defer conn.Close()   //获取客户端的网络地址   cliAddr := conn.RemoteAddr().String()   //创建一个结构体   cli := Client{make(chan string), cliAddr, cliAddr}   //把结构体添加到map   onlineMap[cliAddr] = cli

   //新开一个协程，专门给当前客户端发送信息   go WriteMsgToClient(cli, conn)

   //广播某个人在线   message <- MakeMsg(cli, "login")

   //提示，我是谁   cli.C <- MakeMsg(cli, "I am here")

   var isQuit = make(chan bool)

   hasData := make(chan bool)

   go func() {      buf := make([]byte, 2048)      for true {         n, err := conn.Read(buf)         if n == 0 { //对方断开，或者出问题            isQuit <- true            fmt.Println("conn.read err = ", err)            return         }         msg := string(buf[:n-1])         if len(msg) == 3 && msg == "who" {            conn.Write([]byte("user list : \n"))            for _, tmp := range onlineMap {               msg = tmp.Addr + ":" + tmp.Name + "\n"               conn.Write([]byte(msg))            }         }else if len(msg) >= 8 && msg[:6] == "rename" {            //rename|mike            name := strings.Split(msg,"|")[1]            cli.Name = name            onlineMap[cliAddr] = cli            conn.Write([]byte("user list :\n"))         }else {            message <- MakeMsg(cli, msg)         }      }   }()

   for true {      select {      case <- isQuit:         delete(onlineMap, cliAddr) //当前用户从map移除         message <- MakeMsg(cli, "log out") //广播谁下线了         return      case <- hasData:         //不做操作      case time.After(60*time.Second): //60秒都没有操作了，超时         delete(onlineMap, cliAddr) //当前用户从map移除         message <- MakeMsg(cli, "tiem out") //广播谁下线了         return       }   }}

func Manager()  {   //给map分配空间map   onlineMap = make(map[string]Client)

   for true {      msg := <-message //没有消息前，这里会阻塞      //遍历map,给map每个成员都发送此消息      for _, cli := range onlineMap{         cli.C <- msg      }   }

}

func main() {   //创建监听   listener, err := net.Listen("tcp", ":8000")   if err != nil {      fmt.Println("net.Listen err = ", err)      return   }

   //新开一个协程，用于转发消息，只要有消息到达 ，那就遍历map然后给map每个成员都发送消息   go Manager()

   //主协程，循环阻塞等待用户连接   for true {      conn, err := listener.Accept()      if err != nil {         fmt.Println("listener.Accept err = ", err)         continue //如果这个不发，説不定还有下个发呢      }      //处理用户的连接      go HandleConn(conn)   }}