DubFlag missing, or? about mqttnet HOT 8 CLOSED

If it is missing it is a bug. I also remember adding support for it. Probably I forgot a place. Can you give me some details why you mentioned this?

from mqttnet.

Sure. I'm in the process for creating a cross platform Xamarin MQTT Tester app and was implementing Publish and noticed that the Dub Flag was missing.

from mqttnet.

Cool, let me know if this library works with Xamarin. I also have a app on my wishlist but you are faster.

But what exactly do you mean with the "missing" Dub-Flag? In the MqttApplicationMessage? From my understanding a user cannot set it actively. Only the client can use it internally and let the server know that the message was already sent. Or at least tried.

from mqttnet.

Sure, but in a test scenario that is what you might want to do.

And yes, the library world fine with Xamarin.

from mqttnet.

OK so only for testing purposes but not a real live scenario. I have doubts exposing it. Let me read some documents about MQTT. I will decide then 😄

Awesome. I tried it with Xamarin.Android but it didn't work. The code always stops after ConnectAsync. It simply hangs and I didn't found a solution. The debug output shows zillions of error because lots of .net libraries were not found. Can you tell me what you have done? Anything special beside adding proper app permissions like Internet?

from mqttnet.

I just found that line in the official docs:

It is important to note that the DUP flag refers to the Control Packet itself and not to the Application Message that it contains.

As far as I understand this it means that the Dup flag shall not be exposed to a application message. Only the client uses it internally for its communication retries etc. I also didn't find something else. If I expose it the value must be validated. Sending 0 and it was already tried is a protocol violation. Also sending 1 and it was never sent before is also a violation. So in my opinion this will only produce more problems. What do you think?

from mqttnet.

Sound right. I didn't study the spec that close.

Regarding Xamarin. It just worked. I don't recall any issues.

I'm using it with the latest version of Xamarin. Maybe it's because I've set it up with .Net Standard.

from mqttnet.

Just found this:

DUP flag
The duplicate flag indicates, that this message is a duplicate and is resent because the other end didn’t acknowledge the original message. This is only relevant for QoS greater than 0 and more details are in part 6, which is about QoS levels. This resend/duplicate mechanism is typically handled by the MQTT client library or the broker as an implementation detail.

Also, see here in section 3.3.1.1 Dup in the OASIS 3.1.1. Spec

from mqttnet.