Unable to send gob data over TCP in Go Programming

I have a client server application, using TCP connection

Client:

type Q struct {
    sum int64
}

type P struct {
    M, N int64
}

func main() {
    ...
    //read M and N
    ...
    tcpAddr, err := net.ResolveTCPAddr("tcp4", service)
    ...
    var p P
    p.M = M
    p.N = N
    err = enc.Encode(p)
}

Server:

type Q struct {
    sum int64
}
 
type P struct {
    M, N int64
}
 
func main() {
    ...
    tcpAddr, err := net.ResolveTCPAddr("ip4", service)
    listener, err := net.ListenTCP("tcp", tcpAddr)
    ...
    var connB bytes.Buffer
    dec := gob.NewDecoder(&connB)
    var p P
    err = dec.Decode(p)
    fmt.Printf("{%d, %d}\n", p.M, p.N)
}

The result on serve is {0, 0} because I don't know how to obtain a bytes.Buffer variable from net.Conn.

Is there any way for sending gob variables over TCP ?

If true, how can this be done ? Or there are any alternative in sending numbers over TCP ?

Any help or sample code would really be appreciated.

Here's a complete example.

Server:

package main

import (
	"fmt"
	"net"
	"encoding/gob"
)

type P struct {
    M, N int64
}
func handleConnection(conn net.Conn) {
	dec := gob.NewDecoder(conn)
	p := &P{}
	dec.Decode(p)
	fmt.Printf("Received : %+v", p);
    conn.Close()
}

func main() {
	fmt.Println("start");
   ln, err := net.Listen("tcp", ":8080")
    if err != nil {
    	// handle error
    }
    for {
    	conn, err := ln.Accept() // this blocks until connection or error
    	if err != nil {
    		// handle error
    		continue
    	}
    	go handleConnection(conn) // a goroutine handles conn so that the loop can accept other connections
    }
}

Client :

package main

import (
	"fmt"
	"log"
	"net"
	"encoding/gob"
)

type P struct {
    M, N int64
}

func main() {
	fmt.Println("start client");
	conn, err := net.Dial("tcp", "localhost:8080")
	if err != nil {
		log.Fatal("Connection error", err)
	}
	encoder := gob.NewEncoder(conn)
	p := &P{1, 2}
	encoder.Encode(p)
	conn.Close()
	fmt.Println("done");
}

Launch the server, then the client, and you see the server displaying the received P value.

A few observations to make it clear :

• When you listen on a socket, you should pass the open socket to a goroutine that will handle it.
• Conn implements the Reader and Writer interfaces, which makes it easy to use : you can give it to a Decoder or Encoder
• In a real application you would probably have the P struct definition in a package imported by both programs