go语言 tcp封包LTV格式_go语言解析tlv数据

package main

import (
	"encoding/binary"
	"encoding/json"
	"fmt"
	"io"
	"net"
)

type REQ struct {
   
	Code    int64  //
	Content string // 发送的内容
}

type RESP struct {
   
	Content string // 发送的内容
	Code    int64  //
}

func RecvPck(conn net.Conn) (*REQ, error) {
   
	var sizeBuffer = make([]byte, 2)
	_, err := io.ReadFull(conn, sizeBuffer)
	if err != nil {
   
		fmt.Println("read head err")
		return nil, err
	}
	// 用大端格式读取Size
	size := binary.BigEndian.Uint16(sizeBuffer) //L
	fmt.Printf("L=%d\n", size)

	// 分配包体大小
	body := make([]byte, size)

	// 读取包体数据
	_, err = io.ReadFull(conn, body) //body = T+V
	if err != nil {
   
		fmt.Println("read body err")
		return nil, err
	}

	T := binary.LittleEndian.Uint16(body[:2])
	fmt.Printf("T=%d\n", T)

	req := &REQ{
   }
	err = json.Unmarshal(body[2:], req)
	if err != nil {
   
		return nil, err
	}
	fmt.Printf("V=%+v\n", req)
	return req, nil
}

func SendPck(conn net.Conn, T uint16, req string) error {
   
	resp := &RESP{
   
		Code:    int64(T),
		Content: req,
	}

	json_content, _ := json.Marshal(resp)

	L := len(string(json_content)) + 2
	fmt.Printf("send L=%d\n", L)
	//T := 1
	buffer := make([]byte, L+2)

	// 将包体长度写入缓冲
	binary.BigEndian.PutUint16(buffer, uint16(L))

	tmp := make(
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