tcp 粘包处理 server

server.go

// 参考链接https://feixiao.github.io/2016/05/08/bufio/
package main

import (
	"bytes"
	"encoding/binary"
	"flag"
	"fmt"
	"io"
	"net"
	"strconv"
	"time"
)

var addr = flag.String("addr", "localhost", "The address to listen to; default is \"\" (all interfaces).")
var port = flag.Int("port", 8000, "The port to listen on; default is 8000.")

type Package struct {
	Version [2]int8
	Datalen int64
	Data    []byte
}

func (p *Package) String() string {
	return fmt.Sprintf("Version:%d DataLen:%d Data:%s", p.Version, p.Datalen, p.Data)
}

func (p *Package) Pack(w io.Writer) {
	binary.Write(w, binary.BigEndian, p.Version)
	binary.Write(w, binary.BigEndian, p.Datalen)
	binary.Write(w, binary.BigEndian, p.Data)
}

func (p *Package) Unpack(r io.Reader) {
	binary.Read(r, binary.BigEndian, &p.Version)
	binary.Read(r, binary.BigEndian, &p.Datalen)
	if p.Datalen > 0 {
		p.Data = make([]byte, p.Datalen)
	}
	binary.Read(r, binary.BigEndian, &p.Data)
}

func BuildMsg(data []byte) Package {
	var pkg Package
	pkg.Version[0] = 'V'
	pkg.Version[1] = '1'
	pkg.Data = data
	pkg.Datalen = int64(len(pkg.Data))
	fmt.Printf("%+v\n", pkg)
	return pkg
}

func main() {
	flag.Parse()

	fmt.Println("Starting server...")

	src := *addr + ":" + strconv.Itoa(*port)
	listener, _ := net.Listen("tcp", src)
	fmt.Printf("Listening on %s.\n", src)

	defer listener.Close()

	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Printf("Some connection error: %s\n", err)
		}

		go handleConnection(conn)
	}
}

func handleConnection(conn net.Conn) {
	remoteAddr := conn.RemoteAddr().String()
	fmt.Println("Client connected from " + remoteAddr)

	ech := make(chan error)
	go func(conn net.Conn, ech chan error) {
		buf := make([]byte, 10)
		_, err := conn.Read(buf)
		if err != nil {
			ech <- err
		}
	}(conn, ech)
	tick := time.NewTicker(2 * time.Second)
	for {
		select {
		case <-tick.C:
			handleMessage(conn)
		case err := <-ech:
			fmt.Println(err)
			break
		}
	}

	fmt.Println("Client at " + remoteAddr + " disconnected.")
}

func handleMessage(conn net.Conn) {
	var buf bytes.Buffer
	jsonstring := []byte("t")
	packmsg := BuildMsg(jsonstring)
	fmt.Printf("%v\n", packmsg)
	packmsg.Pack(&buf)
	conn.Write(buf.Bytes())
}