[SOLVED] TransformationException from strip RGB item

Setup, Configuration and Use Items & Sitemaps
1

Hello
I took the instructions to configure an RGB strip from a post by another user. My Hardware is the following: OH 2.4, mosquitto 1.0, MagicHome Alc-01 with Tasmota firmware.
Everything works fine, except for this error when I switch ON / OFF

org.openhab.core.transform.TransformationException: Invalid path '$.Dimmer' in '{"POWER":"OFF"}'
	at org.openhab.core.transform.TransformationHelper$TransformationServiceDelegate.transform(TransformationHelper.java:67) ~[196:org.openhab.core.compat1x:2.4.0]
	at org.openhab.binding.mqtt.internal.MqttMessageSubscriber.processMessage(MqttMessageSubscriber.java:133) [227:org.openhab.binding.mqtt:1.13.0]
	at org.openhab.io.transport.mqtt.internal.MqttBrokerConnection.messageArrived(MqttBrokerConnection.java:570) [234:org.openhab.io.transport.mqtt:1.13.0]
	at org.eclipse.paho.client.mqttv3.internal.CommsCallback.deliverMessage(CommsCallback.java:475) [234:org.openhab.io.transport.mqtt:1.13.0]
	at org.eclipse.paho.client.mqttv3.internal.CommsCallback.handleMessage(CommsCallback.java:379) [234:org.openhab.io.transport.mqtt:1.13.0]
	at org.eclipse.paho.client.mqttv3.internal.CommsCallback.run(CommsCallback.java:183) [234:org.openhab.io.transport.mqtt:1.13.0]
	at java.lang.Thread.run(Unknown Source) [?:?]

item file:

Group  gRGB                 "lights"                      <light>
Color  cucina_Arilux_Color  "cucina RGB"                                   (gRGB,Luci, Zona_giorno)                
String cucina_Arilux_RGB    "colore RGB [%s]"             <colorlight>     (gRGB,Luci, Zona_giorno)              [ "Lighting" ]   {mqtt="<[mosquitto:stat/luce_cucina/RESULT:state:JSONPATH($.Color)]"}
Switch cucina_Arilux_Power  "Luce Cucina RGB [%s]"        <light>          (gRGB,Luci, Zona_giorno)              [ "Lighting" ]   {mqtt=">[mosquitto:cmnd/luce_cucina/POWER:command:*:default],<[mosquitto:stat/luce_cucina/RESULT:state:JSONPATH($.POWER)]", autoupdate="true"}
Dimmer cucina_Arilux_Dim    "dimmer Cucina [%.0f %%]"     <dimmablelight>  (gRGB,Luci, Zona_giorno)              [ "Lighting" ]   {mqtt=">[mosquitto:cmnd/luce_cucina/DIMMER:command:*:default],<[mosquitto:stat/luce_cucina/RESULT:state:JSONPATH($.Dimmer)]"}

while if I act on the dimmer or on the colors it’s all ok. I searched among the various posts but I didn’t find the solution … what doesn’t work?

2

You have a JSON formatted String published to stat/luce_cucina/RESULT that does not include a Dimmer element. I suspect you don’t see an error when you change the Dimmer is because the JSON includes both Dimmer and Power elements so both JSONPATH transformations are able to process the message.

You can ignore the error or you can add a REGEX filter. See the docs for details.

3

I resolved, thanks Rich for the help!!

String cucina_Arilux_RGB    "colore RGB [%s]"             <colorlight>     (gRGB,Luci, Zona_giorno)              [ "Lighting" ]   {mqtt="<[mosquitto:stat/luce_cucina/RESULT:state:JSONPATH($.Color):REGEX((.*))]"}
Switch cucina_Arilux_Power  "Luce Cucina RGB [%s]"        <light>          (gRGB,Luci, Zona_giorno)              [ "Lighting" ]   {mqtt=">[mosquitto:cmnd/luce_cucina/POWER:command:*:default],<[mosquitto:stat/luce_cucina/RESULT:state:JSONPATH($.POWER)]", autoupdate="true"}
Dimmer cucina_Arilux_Dim    "dimmer Cucina [%.0f %%]"     <dimmablelight>  (gRGB,Luci, Zona_giorno)              [ "Lighting" ]   {mqtt=">[mosquitto:cmnd/luce_cucina/DIMMER:command:*:default],<[mosquitto:stat/luce_cucina/RESULT:state:JSONPATH($.Dimmer):REGEX((.*))]"}