[uup]

Having recently implemented a WebSocket service in Go, the Javalin way seems preferable. This is what a similar Go version would look like:

    wsHandler := func(w http.ResponseWriter, r \*http.Request) {
        conn, err := upgrader.Upgrade(w, r)
        if err != nil {
            w.SendStatus(http.StatusInternalServerError)
            return
        }

        ctx, ctxCancel := context.WithCancel(context.Background())
        var wg sync.WaitGroup

        wg.Add(1)
        go func() {
            defer sync.Done()

            for {
                msg, err := conn.ReadMessage()
                if err != nil {
                    return
                }
            }
        }()

        msgPipe := make(chan []byte, 1024)
        wg.Add(1)
        go func() {
            defer wg.Done()
            for {
                select {
                case <-ctx.Done():
                    return
                case msg := <- msgPipe
                    if err := conn.WriteMessage(msg); err != nil { return }
                }
            }
        }()

        go func() {
            <- ctx.Done()
            wg.Wait()
            close(msgPipe)
        }()
    }

I like Go, but I found writing WebSocket code very annoying.