Golang TCPConn Gob通讯

Question

I'm having issues with the gob protocol (or maybe networking in general, where my knowledge is weak), and I don't understand why the following code does not work properly. It is just supposed to be a simple example of maintaining an open TCP connection, and sending multiple gobs through it. The code will send, and receive, but often corrupts its data. Thank you in advance.

package main

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

type Message struct {
    Msg string
}

func main() {
    gob.Register(new(Message))

    clientAddr, err := net.ResolveTCPAddr("tcp", "localhost:12346")
    if err != nil {
        fmt.Println(err)
    }
    serverAddr, err := net.ResolveTCPAddr("tcp", "localhost:12345")
    if err != nil {
        fmt.Println(err)
    }

    serverListener, err := net.ListenTCP("tcp", serverAddr)
    if err != nil {
        fmt.Println(err)
    }
    conn, err := net.DialTCP("tcp", clientAddr, serverAddr)
    if err != nil {
        fmt.Println(err)
    }
    serverConn, err := serverListener.AcceptTCP()
    if err != nil {
        fmt.Println(err)
    }
    done := false
    go func() {
        for !done {
            recieveMessage(serverConn)
        }
    }()
    for i := 1; i < 1000; i++ {
        sent := Message{strconv.Itoa(i)}
        sendMessage(sent, conn)
    }
    time.Sleep(time.Second)
    done = true
}

func sendMessage(msg Message, conn *net.TCPConn) {
    enc := gob.NewEncoder(conn)
    err := enc.Encode(msg)
    if err != nil {
        fmt.Println(err)
    }
}

func recieveMessage(conn *net.TCPConn) {
    msg := new(Message)
    dec := gob.NewDecoder(conn) // Will read from network.
    err := dec.Decode(msg)
    if err != nil {
        fmt.Println(err)
    }
    fmt.Println("Client recieved:", msg.Msg)
}

Answer 1

The problem is that the decoder can buffer data from the next message. When this happens, the next new decoder starts in the middle of a message. The fix is to use a single encoder and decoder.

func main() {
    ...
    dec := gob.NewDecoder(conn) // Will read from network.
    enc := gob.NewEncoder(serverConn)
    go func() {
        for !done {
            recieveMessage(dec)
        }
    }()

    for i := 1; i < 1000; i++ {
        sent := Message{strconv.Itoa(i)}
        sendMessage(sent, enc)
    }
    ...
}

func sendMessage(msg Message, enc *gob.Encoder) {
    err := enc.Encode(msg)
    if err != nil {
        fmt.Println(err)
    }
}

func recieveMessage(dec *gob.Decoder) {
    msg := new(Message)
    err := dec.Decode(msg)
    if err != nil {
        fmt.Println(err)
    }
    fmt.Println("Client recieved:", msg.Msg)
}

Run it in the playground