GO语言UDP小笔记

<pre style="margin-top: 0px; margin-bottom: 0px;"><span style=" color:#0000ff;">package</span><span style=" color:#f57900;"> </span>main

import (

    "fmt"

    "net"

    "time"

)

func main() {

    udpaddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:1789")

    if err != nil {

        fmt.Println(err)

        return

    }

    lis, err := net.ListenUDP("udp", udpaddr)

    if err != nil {

        fmt.Println(err)

        return

    }

    defer lis.Close()

    for {

        buf := make([]byte, 512)

        n, addr, err := lis.ReadFromUDP(buf)

        if err != nil {

            fmt.Println(err)

            continue

        }

        str := string(buf[:n])

        go func(lis *net.UDPConn, addr *net.UDPAddr, body string) {

            lis.WriteToUDP([]byte(body), addr)

            time.Sleep(3e9)

        }(lis, addr, str)

    }

}

package main
 
import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"os"
)
 
type Fileinfo struct {
	Name string
	Path string
}
 
func server() {
	laddr := &net.UDPAddr{IP: []byte{127, 0, 0, 1}, Port: 1789}
	con, err := net.ListenUDP("udp", laddr)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer con.Close()
	for {
		Buf := make([]byte, 1024)
		n, raddr, _ := con.ReadFromUDP(Buf)
		var info Fileinfo
		json.Unmarshal(Buf[:n], &info)
		if info.Name != "" {
			if info.Path != "" {
				e := os.Chdir(info.Path)
				if e != nil {
					con.WriteTo([]byte(e.Error()), raddr)
					continue
				}
			}
			con.WriteToUDP([]byte("OK"), raddr)
			File, _ := os.Create(info.Name)
			defer File.Close()
			for {
				Buf := make([]byte, 4096)
				n, r, _ := con.ReadFromUDP(Buf)
				if r.String() != raddr.String() {
					continue
				}
				if n == 4 && bytes.Contains([]byte{0, 69, 79, 70}, Buf[:n]) {
					File.Sync()
					File.Close()
					break
				}
				File.Write(Buf[:n])
			}
		}
	}
}
 
func client() {
	con, e := net.Dial("udp", "127.0.0.1:1789")
	if e != nil {
		fmt.Println(e)
		return
	}
	defer con.Close()
	var info Fileinfo = Fileinfo{Name: "WinMD5.exe", Path: "D:"}
	b, _ := json.Marshal(info)
	con.Write([]byte(b))
	Buf := make([]byte, 1024)
	n, _ := con.Read(Buf)
	if string(Buf[:n]) == "OK" {
		File, _ := os.Open("3.go")
		for {
			Buf := make([]byte, 4096)
			n, e := File.Read(Buf)
			if e != nil {
				if e == io.EOF {
					break
				}
				fmt.Println(e)
				break
			}
			con.Write(Buf[:n])
		}
		con.Write([]byte{0, 69, 79, 70})
	}
}