Delay PUBACK till after message processing using QoS 1

[Lacutas82]

I'd like to perform some processing on the received message before acknowledging that it's been received correctly. Is there a way to delay sending of the PUBACK under QoS 1 until after some processing has been completed?

[chkr1011]

You can set the "AutoAcknowledge" to false and call "AcknowledgeAsync" after you finishes your stuff.

[Lacutas82]

Thank you for this!

[Rohit03sahu]

@chkr1011

I have been looking for the same thing like how can we control the Acknowledge QOS=1.

Could you please provide us any example for mqttnet c# library ?

[Lacutas82]

@Rohit03sahu
I haven't tested this as have been working on something else, but I'm presuming something like this would delay the acknowledgement until you're ready to actually do it.

await mqttClient.ConnectAsync(mqttClientOptions);

mqttClient.ApplicationMessageReceivedAsync += delegate(MqttApplicationMessageReceivedEventArgs eventArgs)
{
    eventArgs.AutoAcknowledge = false;
    
    Console.WriteLine(eventArgs.ApplicationMessage.Topic);
    
    eventArgs.AcknowledgeAsync(CancellationToken.None);

    return Task.CompletedTask;
};

[delphikit]

Would this also be possible with ApplicationMessageSkippedAsync?