CODEWITHSUNDEEP
socketsunixgo
user972946
user972946

Reputation:

Server does not get message in a "Hello World" socket program

I am practicing to use Unix socket together with bufio. This is the program:

    // Register server socket
    os.Remove("serversock")
    socket, err := net.ListenUnix("unix", &net.UnixAddr{"serversock", "unix"})
    if err != nil {
        panic(err)
    }
    go func() {
        for {
            // Accept new connection
            conn, err := socket.Accept()
            if err != nil {
                panic(err)
            }
            fmt.Println("Got connection")
            reader := bufio.NewReader(conn)
            line, err := reader.ReadString(byte('\n'))
            if err != nil {
                panic(err)
            }
            fmt.Println("Got line", line)
        }
    }()
    // Client connection
    conn, err := net.DialUnix("unix", nil, &net.UnixAddr{"serversock", "unix"})
    writer := bufio.NewWriter(conn)
    n, err := writer.WriteString("hello world\n")
    if err != nil {
        panic(err)
    }
    fmt.Println("Written", n)
    // Client wait
    time.Sleep(1 * time.Second)

When it runs, it prints:

Written 13
Got connection

And then exists, so the server does not seem to get the message. What did I do wrong?

Upvotes: 1

Views: 218

Answers (1)

Not_a_Golfer
Not_a_Golfer

Reputation: 49245

Your writer is buffered, it doesn't flush the buffer when you WriteString() to it. Simply call writer.Flush() and it will actually send the line. You can also try writing directly to the socket and see what happens.

Also your accept loop should look like this:

go func() {
    for {
        // Accept new connection
        conn, err := socket.Accept()
        if err != nil {
            panic(err)
        }
        fmt.Println("Got connection")
        reader := bufio.NewReader(conn)

        //spawn a goroutine that has a read loop
        go func(reader *bufio.Reader) {
           for {
             line, err := reader.ReadString(byte('\n'))
             if err != nil {
                panic(err)
             }
             fmt.Println("Got line", line)
           }
        }(reader)
    }
}()

Upvotes: 1

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