How to access request object or context about gws HOT 9 CLOSED

If you don't care about performance loss, you can write your own.

func IsCanceled(ctx context.Context) bool {
	select {
	case <-ctx.Done():
		return true
	default:
		return false
	}
}

func WriteWithContext(ctx context.Context, socket *gws.Conn, op gws.Opcode, p []byte) error {
	if IsCanceled(ctx) {
		return ctx.Err()
	}

	ech := make(chan error)

	go func() {
		ech <- socket.WriteMessage(op, p)
	}()

	select {
	case err := <-ech:
		return err
	case <-ctx.Done():
		return ctx.Err()
	}
}

from gws.

Take a look at gws.Conn{}.Session()

from gws.

gws.Conn{}.Session()

Thanks.

Do you mean as an alternative to using context?

I can store in the concurrent map values using session - to save the session object into the session storage, etc.

It will work as a workaround, but I was hoping for a solution more in line with the conventional use of context.

from gws.

gws encapsulates the readMessage loop, which can only read data from *gws.Conn in the event callback method. I wouldn't consider exporting the readMessage method, the disruption to the existing API design would be too great.

from gws.

Too many ways to accomplish the same thing can cause problems for some users.

from gws.

Well, that may be the case. But context is a part of the standard library and API for Golang these days.

Anyhow, passing context via session storage causes an issue - namely, the context is canceled:

func (handler) OnMessage(socket *gws.Conn, message *gws.Message) {
	defer func() {
		if err := message.Close(); err != nil {
			log.Error().Err(err).Msg("failed to close message")
		}
	}()
	if message.Data != nil && message.Data.Len() > 0 && message.Opcode == gws.OpcodeText {
		// We are retrieving the request context we passed into the socket session.
		value, exists := socket.Session().Load("context")
		if !exists {
			log.Error().Msg("failed to load context from session")
			socket.WriteClose(statusWSServerError, []byte("invalid context"))
			return
		}
		ctx := value.(context.Context)

		if ctx.Err() != nil {
			panic(ctx.Err())
		}
                // .... code will not reach here because the context is cancelled. 
}

func promptTestingWebsocketHandler(w http.ResponseWriter, r *http.Request) {
	socket, err := upgrader.Upgrade(w, r)
	if err != nil {
		log.Error().Err(err).Msg("failed to upgrade connection")
		apierror.InternalServerError().Render(w, r)
		return
	}

	socket.Session().Store("context", r.Context())
	go socket.ReadLoop()
}

from gws.

You are talking about context.Context, sorry for my mistake.

Gws pursues extreme performance and won't support context.Context, it has too much overhead. You can use SetDeadline instead.

from gws.

ok, thanks for clarifying this

from gws.

If you don't care about performance loss, you can write your own.

func IsCanceled(ctx context.Context) bool {
	select {
	case <-ctx.Done():
		return true
	default:
		return false
	}
}

func WriteWithContext(ctx context.Context, socket *gws.Conn, op gws.Opcode, p []byte) error {
	if IsCanceled(ctx) {
		return ctx.Err()
	}

	ech := make(chan error)

	go func() {
		ech <- socket.WriteMessage(op, p)
	}()

	select {
	case err := <-ech:
		return err
	case <-ctx.Done():
		return ctx.Err()
	}
}

Thanks, for now, I simply extract the values I need from context and use session storage to pass them. This, though, is also not so performant in the end. I don't need to use cancellation - rather, context is used to pass data from middleware etc. The websocket is mounted on a sub path inside an existing application, and there are layers of authentication and authorization that inject values from the DB into the context.

from gws.