Can I publish to MQTT from either a rule or item state?

Setup, Configuration and Use Runtime
1

I’m pretty happy with MQTT for incoming information, and sending commands.

But I’d like to publish something back to the MQTT server. States, or warning messages etc.

How can I do this?

2 
String      VT_Notify_Trace                     { mqtt=">[mosquitto:/openhab/notification/trace:state:*:default]" }
String      VT_Notify_Info                      { mqtt=">[mosquitto:/openhab/notification/info:state:*:default]" }
String      VT_Notify_Alert                     { mqtt=">[mosquitto:/openhab/notification/alert:state:*:default]" }
String      VT_Notify_Warn                      { mqtt=">[mosquitto:/openhab/notification/warn:state:*:default]" }
String      VT_Notify_Alarm                     { mqtt=">[mosquitto:/openhab/notification/alarm:state:*:default]" }
3

Then to publish an alert you just do VT_Notify_Alert.postUpdate("Front door has been left open for 30mins!")

4

Ahh right, so in a rule, I go
VT_Notifity_Trace.postUpdate("Notification message")
and that will push "Notification Message to mqtt on topic /openhab/notification/trace

5

Correct - then you setup your various mqttwarn targets to watch the different notification topics, and route the messages to the appropriate end points and devices.

Means very easy to add a new device or remove one, or add a new notification type, without having to touch any rules.

6

That’s really elegant. And then it’s into MQTTWarn for processing. And in my case I have my boxcar code…since I still have the app, and the code I wrote for it.

7

IMG_8032

And done.

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