JSON Transformation problem with TASMONA MQTT bin

[rossko57]

An alternative approach for users of MQTT binding 2.5M1 onwards.
Chained transformation - REGEX to select on POWER1,POWER2 etc. ans then JSONPATH as usual

MQTT 2.5 M1+ How to implement the equivalent to MQTT1 REGEX filters

Problem In the MQTT1 binding there was a feature that let us filter messages published to a given topic and only pass those that match a given REGEX to the transformation and/or on to the Item. This was useful to handle devices that publish messages to a single well known topic for all their devices. For example, the official firmware from the vendor of Shelly devices have a request/response protocol over MQTT to get meta data about the devices (IP address, MAC address, firmware version, whethe…