An application message received from the broker.


Additional details can be found in the ApplicationMessagePacketBuilder documentation.

  • bool IsDuplicate

    true if it’s not the first ocassion the broker sent this application message. An application message can duplicated if it has been sent with a QoS level greater than 0 and and it’s not the first time the broker tries to deliver it.

  • QoSLevels QoS

    QoS level this application message sent with.

  • bool Retain

    true if this is a retained application message.

  • string Topic

    The topic’s name this application message is publish to.

  • PayloadTypes PayloadFormat

    Payload type (binary or text).

  • TimeSpan ExpiryInterval

    Expiry interval of the application message. If this is a retained application message ExpiryInterval this value is the original value the application message is sent with minus the time the message has been waiting on the broker.

  • string ResponseTopic

    Topic name where the publisher waiting for a response to this application message.

  • BufferSegment CorrelationData

    Arbitrary data sent with the application message. When a new message is published to the ResponseTopic as a response to this message, this CollectionData should be sent too.

  • List<KeyValuePair<string, string» UserProperties

    Arbitrary key-value pairs sent with the application message.

  • string ContentType

    Arbitrary content type set by the publisher.

  • BufferSegment Payload

    Payload of the application message.


Receive and use textual payload:

void OnMessage(MQTTClient client, SubscriptionTopic topic, string topicName, ApplicationMessage message)
    // Convert the raw payload to a string
    var text_payload = System.Text.Encoding.UTF8.GetString(message.Payload.Data, message.Payload.Offset, message.Payload.Count);

    // Print out the Content-Type value and the text payload
    Debug.Log($"Content-Type: '{message.ContentType}' Payload: '{text_payload}'");