MQTT 2.4 Binding: Number as state topic and incoming value transformation is not working

Setup, Configuration and Use Beginners
1

Hi everybody,
after some evenings spending my time in reading posts and try some trial and error I dont know what to do.
I have openhab 2.4 running on my raspberry.
The connection via MQTT Mosquitto from the MQTT 2.4 binding and the ESP8266 (Tasmota firmware) is working.
I can see the messages in MQTT.fx.
Unfortunately if I try to show the distance of my HC-SR04 (connected on the ESP8266) I see only “NaN”.
Acc. to MQTT.fx the state topic from the ESP is:
tele/GarageESP/SENSOR
{“Time”:“2020-05-07T21:54:54”,“SR04”:{“Distance”:90.667}}

The Thing in openhab has a chanel with following configuaration:
MQTT state topic: tele/GarageESP/SENSOR
Incoming value transformation: “JSONPATH:$.SR04.Distance”
The linked Item is default.
transformation-jsonpath - 2.4.0 is also installed.

I hope someone can help me.

Best regards
Bastian

2

Errors in the log?

3

You may want to upgrade as OH 2.4 is over a year old.

4

Hi,

this is the log file:
2020-05-08 17:38:29.344 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service “JSONPATH for pattern $.SR04.Distance” not found!

2020-05-08 17:38:29.348 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload ‘{“Time”:“2020-05-08T16:38:29”,“SR04”:{“Distance”:28.947}}’ not supported by type ‘NumberValue’

5

You do not have the JSONPATH Transformation installed.

6

If I go to Add-ons and Transformations I can see that the transformation-jsonpath - 2.4.0 is installed. Its also blue on the icon.

7

Trying to test the JSONPATH in various JSON testers indicate that {“Time”:“2020-05-08T16:38:29”,“SR04”:{“Distance”:28.947}} is not valid JSON. I’m not good enough at JSON to say why it’s invalid but there is something wrong with it.

8

The message is clear and specific. The JSONPATH transformation is not available.
I think I’d uninstall/reinstall to see if something is stuck in its throat.

9

Man oh man. Manchmal soll’s halt so sein.
Danke für die Denkanstöße, haben mir geholfen meinen blöden Fehler zu finden.
Habe die die Hochkommas mitgeschrieben “JSONPATH:$.SR04.Distance”, wenn ich es so schreibe gehts JSONPATH:$.SR04.Distance
Vielen Dank und bestimmt demnächst.

10

Error message was quite right. Even I didn’t read it literally enough, the “JSONPATH:$.SR04.Distance” persistence service wasn’t installed at all :crazy_face: