MQTT: player channel state & outgoing timestamp

Setup, Configuration and Use Beginners
1

There’s a few questions about how to get the value of Player channel states/commands as a string value, but it seems an MQTT Thing doesn’t publish these. The appear in debug/API as a plain text commands such as PREVIOUS, PLAY, PAUSE, NEXT etc. I have a player control set up next to a String value in a MQTT follow channel.

I’m also seeing a need to sync up the localised events in OpenHAB with the broker, as other MQTT clients will receive inaccurate message times if they are retained. They will be delivered like a flood and not reflect the actual time of the event.

The MQTT binding doesn’t mention Player channels, or a timestamp value: https://www.openhab.org/addons/bindings/mqtt.generic/

My Outgoing Value Format set in the MQTT Thing is simplistic:

{"attribute": "player", "value": "%s", "timestamp": "%t"}

Does anyone know how to achieve what’s above? The documentation seems scant.

2

What does %t mean in a string format?

You can build you json string in a rule then send that to the MQTT string channel.

Here is an example for a aircon.

What version of the mqtt binding are you using?

3

Using the latest binding. The variable %t was just an arbitrary value to indicate a timestamp or datetime value which would be helpful to have in the binding if it’s not there already.

We can’t do all that on every OpenHAB instance just for a text string like we get with the others. Isn’t there an actual event sent from the channel?

4

You could subscribe to the broker to always add timestamps to mqtt messages.

You can skip using things and just use a MQTT action to sent message

Then it would look something like


rule "Player State to MQTT"
when
  Item Tv received command
then

  val timestamp = new DateTimeType()
  val value = '{\"attribute\": \"player\", \"value\": \"' + receivedCommand + '\", \"timestamp\": \"' + timestamp + '\"}'  
  
  val actions = getActions("mqtt","mqtt:broker:myMQTTBroker") // myMQTTBroker is the name of my broker yours may be different
  actions.publishMQTT("tv/player",value)    
  logInfo("publishMQTT", value )
end