JSON Format for Topics

A JSON object describing an MQTT topic has the following syntax:

{
  "@Skill.MQTT.Topic": {
    "name": "Axis 1 Motor Temperature",
    "UUID": "d8cf1aa4-f484-4fc1-abe7-5f594640915a",
    "ACL": { ... },
    "topic": "axis-1/motor/temperature",
    "payload": ...,
    "extraAttributes": [
      "changeTime",
      "error"
    ],
    "QoS": 0,
    "retained": false,
    "requiredForBirth": false
  }
}

Object Members

name	A string value containing the name of the topic. The name is used to construct the topic’s primary key.
UUID	A string value containing the unique UUID of the topic.
ACL	An optional JSON object containing the element ACL of the topic. The format of the object is described under JSON Format for ACLs in the Xentara user manual.
topic	A string value containing the topic of the message. See 3.3.2.1 Topic Name in the MQTT specification for details.
payload	A JSON string value or a JSON object containing the payload of the messages for this topic. The format of the value is described under JSON Format for Message Payloads. See 3.3.3 PUBLISH Payload in the MQTT specification for details.
extraAttributes	An optional JSON array containing additional attributes that should be included in data point value payloads. The value and quality attributes are always included automatically, and must not appear in the array. It is not considered an error if the data point included in the payload does not provide all of the additional attributes. Any attributes not provided by the data point will simply be omitted from the payload. This allows you to include attributes like “error” or “writeTime” in this list, that may not be supported by all data points.
QoS	An optional numeric value containing the quality of service to use for the messages. The QoS must be 0, 1, or 2. See 3.3.1.2 QoS in the MQTT specification for details. If you do not specify this parameter, then a QoS of 0 will be used.
retained	An optional Boolean value specifying whether the messages should be retained by the broker. See 3.3.1.3 RETAIN in the MQTT specification for details. If you do not specify this parameter, then the messages will not be retained.
requireForBirth	An optional Boolean value specifying whether the birth message should be delayed until this message has been published at least once. If you do not specify this parameter, then the birth message will be delayed if and only if the retained option is set.