golang 简易聊天

client.go
------------------------------
package main

import (
    "net"
    "fmt"
    "bufio"
    "echo/codec"
    "time"
)

var quitSemaphore chan bool

func main() {
    var tcpAddr *net.TCPAddr
    tcpAddr,_=net.ResolveTCPAddr("tcp","127.0.0.1:9999")
    conn,_:=net.DialTCP("tcp",nil,tcpAddr)  //开启连接
    defer conn.Close() //关闭连接
    fmt.Println("Connected!")
    go onMessageRecived(conn) //接收消息
    go sendMessage(conn) //发送消息
    <-quitSemaphore
}

// 发送消息
func sendMessage(conn *net.TCPConn)  {
    //发送消息
    for{
        time.Sleep(1 * time.Second)
        var msg string
        fmt.Scanln(&msg)
        if msg == "quit"{
            quitSemaphore <- true
            break
        }
        //lk
        //b :=[]byte(msg +"\n")
        //处理加密
        b ,_ := codec.Encode(msg+"\n")
        conn.Write(b)
    }
}

server.go
-----------------------------
package main

import (
    "bufio"
    "fmt"
    "net"
    "echo/codec"
)

// 用来记录所有的客户端连接
var ConnMap map[string]*net.TCPConn

func main() {
    var tcpAddr *net.TCPAddr
    ConnMap = make(map[string]*net.TCPConn) //初始化
    tcpAddr,_=net.ResolveTCPAddr("tcp","127.0.0.1:9999")

    tcpListener,_:=net.ListenTCP("tcp",tcpAddr) //开启tcp 服务
    //退出时关闭
    defer tcpListener.Close()
    for{
        tcpConn,err :=tcpListener.AcceptTCP()
        if err !=nil {
            continue
        }
        fmt.Println("A client connected : "+ tcpConn.RemoteAddr().String())
        // 新连接加入 map
        ConnMap[tcpConn.RemoteAddr().String()] = tcpConn

        go tcpPipe(tcpConn)
    }
}
//处理发送过来的消息
func tcpPipe(conn *net.TCPConn)  {
    ipStr :=conn.RemoteAddr().String()
    defer func() {
        fmt.Println("disconnected : "+ ipStr)
        conn.Close()
    }()
    //读取数据
    reader :=bufio.NewReader(conn)
    for {
        message ,err :=codec.Decode(reader)//reader.ReadString('\n')
        if err != nil {
            return
        }
        fmt.Println(string(message))
        //这里返回消息改为广播
        boradcastMessage(conn.RemoteAddr().String()+":"+string(message))
    }
}
//广播给其它 
func boradcastMessage(message string)  {
    //遍历所有客户端并发消息
    for _,conn :=range ConnMap{
        b,err :=codec.Encode(message)
        if err != nil {
            continue
        }
        conn.Write(b)
    }
}

codec.go
------------------------
package codec

import (
    "bytes"
    "encoding/binary"
    "bufio"
)

func Encode(message string) ([]byte, error) {
    // 读取消息的长度
    var length int32 = int32(len(message))
    var pkg *bytes.Buffer = new(bytes.Buffer)
    // 写入消息头
    err := binary.Write(pkg, binary.LittleEndian, length)
    if err != nil {
        return nil, err
    }
    // 写入消息实体
    err = binary.Write(pkg, binary.LittleEndian, []byte(message))
    if err != nil {
        return nil, err
    }

    return pkg.Bytes(), nil
}

func Decode(reader *bufio.Reader) (string, error) {
    // 读取消息的长度
    lengthByte, _ := reader.Peek(4)
    lengthBuff := bytes.NewBuffer(lengthByte)
    var length int32
    err := binary.Read(lengthBuff, binary.LittleEndian, &length)
    if err != nil {
        return "", err
    }
    if int32(reader.Buffered()) < length+4 {
        return "", err
    }

    // 读取消息真正的内容
    pack := make([]byte, int(4+length))
    _, err = reader.Read(pack)
    if err != nil {
        return "", err
    }
    return string(pack[4:]), nil
}

func onMessageRecived(conn *net.TCPConn)  {
    reader :=bufio.NewReader(conn)
    for {
        //解密
        msg,err := codec.Decode(reader)//reader.ReadString('\n')
        fmt.Println(msg)
        if err !=nil {
            quitSemaphore <- true
            break
        }
    }
}