Hi,
I’m very interested in this approach and tried it, but I can’t make it work…
I installed openhabian on a separate PI. I installed MQTT on that PI as well and configured Domoticz to update that MQTT broker. That seems working, because when I use a tool like mqtt-spy-1.0.0.jar I can indeed view domoticz messages coming out.
I tried to follow the guidelines from this thread, but I can’t see anything in Openhab… So I probably made a mistake somewhere.
First, I installed openhab2.4, the latest version… I initially installed the new MQTT binding. As I couldn’t get any success with the procedure, I uinstalled (using PaperUI) that binding and used PaperUI again to install the “MQTT Binindg 1.x”
-> now, I get an error in Openhab, stating that the Openhab Thing “MQTT Broker” is “uninitialized” (even after having rebooted the PI) : Is it because I only used the PaperUI to install the binding? Do I need to create a configuration file manually ? In a openhab tutorial for MQTT 1.x, I could read that a file mqtt.cfg has to be created or modified manually in /services folder : is it something to be done though not described in the step by step guide of this thread ?
I read in an openhab doculentation (MQTT Things and Channels - Bindings | openHAB) that some files in .things are required, like the demo1.things described in that page. Is it something to be done and is it not overlapping with the .items definitions described by Ankan ?
-> Another question is how to understand naming strategy :
Where should I setup “idx123” ? Is it Domoticz, but then we lose a full description ? Or in openhabian, but then I don’t understand where to define that… Are they created and named automatically thanks to the .items file suggested by Ankan ? The first item in the file from Ankan starts with “idx123”, but not the second line (for outdoortemperature), so I feel lost : does it mean that naming system is constrained (with need to use idx+number) only for devices subject to “2 ways updates” (ie from domoticz to openhabian and from openhabian to domoticz) ?
-> also, as I like understanding (at least trying), could someone explain to me the syntax of the jsonpath:
JSONPATH($.svalue1):(?s).idx".?.?.?124,.
I understand it looks for svalue1, but I don’t understand the remaining structure (the ?s, and the multiple dots ?.?.?124 ). I tried to look at jsonpath syntax, but could not find such example
→ Last but not least : despite this work was done using MQTT Binding 1.x, do you think it will work with the new MQTT Binding 2 for openhab 2.4 ?
I’d highly appreciate if anyone could help me. This is driving me nuts ! 
br,
Ricorico94