TCP Server | Discord Gophers | Page 1

mighty flower Jul 18, 2024, 7:33 PM

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why are you using JSON here? it isn't totally clear to me

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and to be clear: what bytes are actually being sent over the wire? are they TestUser or "TestUser" (with the quotation marks actually being sent as individual bytes)?

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TestUser is not a valid JSON value. "TestUser" is. (and while it's totally legal to send a string as a JSON value—it doesn't necessarily have to be an object or array—it's not necessarily typical)

storm oracle Jul 18, 2024, 8:00 PM

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I think the issue might be with my client because I can fmt.PrintLn() at the start of the handler function and that prints out immediately.

mighty flower Jul 18, 2024, 8:00 PM

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(i ask mostly to confirm that you know that you need a self-terminating format if you're not using a length-describing format. JSON does provide that so it's actually positive in that way, but it's so inefficient at conveying arbitrary non-UTF-8 bytes that it usually isn't the best way to do such a thing in a network protocol.)

storm oracle Jul 18, 2024, 8:02 PM

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Actor replication would use udp so that would be just raw bytes.

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I'm going to keep troubleshooting some more on the client

mighty flower Jul 18, 2024, 8:03 PM

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taking a network capture in the middle would be a great way to identify the problematic endpoint

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either you see the bytes or you don't, at which point it should be clear where to look further

storm oracle Jul 18, 2024, 8:08 PM

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Yea, I didn't have json setup on the client. That appears to have been the issue (other than that I wasn't running the network update function inside the new game loop).

mighty flower Jul 18, 2024, 8:11 PM

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that's why i asked 😁 the decoder is just going to keep reading until it sees a terminating character

storm oracle Jul 18, 2024, 8:55 PM

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func recvLoop(r io.Reader) (string, error) {
    var inbuf [64]byte
    var result strings.Builder

    for {
        n, err := r.Read(inbuf[:])
        if err != nil {
            fmt.Println("Failed to receive msg from the server!")
            break
        }
        result.Write(inbuf[:n])
        fmt.Print(string(inbuf[:n]));
    }
    return result.String(), nil
}

func handleConnection(conn net.Conn) {
    defer conn.Close()
    fmt.Println("TEST!")

    var client Client
    client.Conn = conn

    // Create buffered reader and writer
    reader := bufio.NewReader(conn)
    //writer := bufio.NewWriter(conn)

    // Read username
    fmt.Println("Convert to str");
    data, err := recvLoop(reader)
    fmt.Println("Done recvLoop");
    if err != nil {
        fmt.Println("Error receiving data:", err)
        return
    }
    fmt.Println("data: ", data);
    // if err != nil {
    //     fmt.Println("Error reading username:", err)
    //     return
    // }
    client.Username = data // Remove newline character

    lobby.Mutex.Lock()
    lobby.Clients = append(lobby.Clients, &client)
    lobby.Mutex.Unlock()

    fmt.Println(client.Username, "joined the lobby")

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Server started on port 64010
TEST!
Convert to str
"TestUser"

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After closing the game

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"TestUser"Failed to receive msg from the server!
Done recvLoop
data:  "TestUser"
"TestUser" joined the lobby
Error reading message: read tcp 127.0.0.1:64010->127.0.0.1:50228: wsarecv: An established connection was aborted by the software in your host machine.

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Actually, I think I know what's going on

#TCP Server