问题描述：
实现一个网络聊天室服务端。完成之后你将熟悉select、net库、time定时器的用法。
要点：
用户发来的消息广播给所有接入聊天室的用户。
新用户进入的时候能收到聊天室所有其他用户的名字列表。
使用netcat工具作为客户端。
拓展：
当用户不活跃的时间超过指定时间后，断开用户的连接。
代码：
import (
"bufio"
"fmt"
"log"
"net"
"time"
)
type client struct {
Out chan<- string
Name string
}
var (
entering = make(chan client)
leaving = make(chan client)
messages = make(chan string)
)
var timeout = 10 * time.Second
func broadcaster() {
clients := make(map[client] bool)
for {
select {
case msg := <-messages:
for cli := range clients {
cli.Out <- msg
}
case cli := <-entering:
clients[cli] = true
cli.Out <- "Present:"
for c := range clients {
cli.Out <- c.Name
}
case cli := <-leaving:
delete(clients, cli)
close(cli.Out)
}
}
}
func handleConn(conn net.Conn){
out := make(chan string, 10)
go clientWriter(conn, out)
in := make(chan string)
go clientReader(conn, in)
var who string
var nameTimer = time.NewTimer(timeout)
out <- "Enter your name:"
select {
case name := <-in:
who = name
case <-nameTimer.C:
conn.Close()
return
}
cli := client{out, who}
out <- "You are " + who
messages <- who + " has arrived"
entering <- cli
idle := time.NewTimer(timeout)
Loop:
for {
select {
case msg := <-in:
messages <- who + ": " + msg
idle.Reset(timeout)
case <-idle.C:
conn.Close()
break Loop
}
}
leaving <- cli
messages <- who + " has left"
conn.Close()
}
func clientWriter(conn net.Conn, ch <-chan string) {
for msg := range ch{
fmt.Fprintln(conn, msg)
}
}
func clientReader(conn net.Conn, ch chan<- string) {
input := bufio.NewScanner(conn)
for input.Scan() {
ch <- input.Text()
}
}
func main() {
listener, err := net.Listen("tcp", "localhost:8088")
if err != nil{
log.Fatal(err)
}
go broadcaster()
for {
conn, err := listener.Accept()
if err != nil{
log.Print(err)
continue
}
go handleConn(conn)
}
}
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