[Observable] Set CON/NON for notifications

[palsivertsen]

RFC7641 states:

A notification can be confirmable or non-confirmable, i.e., it can be
sent in a confirmable or a non-confirmable message. The message type
used for a notification is independent of the type used for the
request and of any previous notification.

The ResponseWriter and Message interfaces are both missing an option to set the type of a message to CON/NON.

Is there a way to set message type for a notification when responding to a observe request?

[jkralik]

Request contains client that provides call NewMessage.
Eg:

req.Client.NewMessage(coap.MessageParams{
   	Type:  NonConfirmable,
   	...
})

Is it helps you?

[palsivertsen]

Yes, that would help. Thanks!

[palsivertsen]

Shouldn't coap.ResponseWriter.WriteMsg if there's no ACK of a CON message?

I'm running the observe client/server example like so:
server/main.go:

....
func sendResponse(w coap.ResponseWriter, req *coap.Request, subded time.Time) error {
  resp := req.Client.NewMessage(coap.MessageParams{
    Type: coap.Confirmable,
    Code: coap.Content,
  })  
  resp.SetOption(coap.ContentFormat, coap.TextPlain)
  resp.SetObserve(5)
  resp.SetPayload([]byte(fmt.Sprintf("Been running for %v", time.Since(subded))))
  return w.WriteMsg(resp)
}
...

[jkralik]

But i think you need to set Token and MessageId(for udp) because the client cannot pair notification..... something like:

func sendResponse(w coap.ResponseWriter, req *coap.Request, subded time.Time) error {
  resp := req.Client.NewMessage(coap.MessageParams{
    Type: coap.Confirmable,
    Code: coap.Content,
    MessageID: req.Msg.MessageID(),
    Token:     req.Msg.Token(),
  })  
  resp.SetOption(coap.ContentFormat, coap.TextPlain)
  resp.SetObserve(5)
  resp.SetPayload([]byte(fmt.Sprintf("Been running for %v", time.Since(subded))))
  return w.WriteMsg(resp)
}
...

[jkralik]

I will close this issue. Please if you have still problem please reopen it. Thx