How do you parse JSON in OH3 MQTT Thing?

TinkerMan · October 30, 2022, 8:57am

Hi all. I am new to OH3. How do I get single values out of a JSON string?

{"temp1":55.06,"temp2":49.38,"temp3":53.63,"temp4":50.12,"WiFi":86}

I need temp1.

Is the Transformation like this?

`UID: mqtt:topic:c92e3237df:1a1866b5d8
label: Hot Water Temperature
thingTypeUID: mqtt:topic
configuration: {}
bridgeUID: mqtt:broker:c92e3237df
channels:

id: HotWater
channelTypeUID: mqtt:number
label: Hot Water Temperature
description: “”
configuration:
stateTopic: Water/HeaterValues
transformationPattern: JSONPATH:$.temp1
unit: °C`

Thanks

TinkerMan · October 30, 2022, 9:27am

If I use it on the Channel I see nothing

TinkerMan · October 30, 2022, 9:54am

If I change it all to string then I see the full JSON in the Item. So it seems like the transform does not happen

Wolfgang_S · October 30, 2022, 10:00am

Is the JSONPath transformation installed on your system ?

TinkerMan · October 30, 2022, 10:38am

Aaa Probably not if it does not come as standard with the OH3 install. Let me see how to install that then

TinkerMan · October 30, 2022, 10:50am

OK thanks all working now. One would think that if you can configure a setting on the Channel that it will have the code behind it to use it.