Fetching MQTT using JSON filter

[Wiki]

My brandnew Volkszähler using Tasmota sends its data to mosquitto using the format:

Code: Select all

tele/Zaehler/SENSOR = {"Time":"2022-11-14T15:24:00","SML":{"Verbrauch":1.474,"Einspeisung":0.770,"Watt":26.000}}

How can I define a filter in MQTT Import to get hands on the value of "Watt"?

[Ath]

You should enable Parse JSON message by having that option on Yes, set one of 4 'Topic's to "tele/Zaehler/SENSOR" and the corresponding 'JSON Attribute' to "Watt". (all values/names without the quotes )

[Wiki]

That's what I've tried the very first, but I can see in the log "tele/Zaehler/SENSOR#Watt=null" resp Watt paylod null, the value of the related field says "nan".
The problem seems to be the "nested" JSON information. Means, the JSON parameters are in double brackets as you can see in my first post. First JSON parameter group (or however its called) is Time, second is "SML".

Setting JSON attribute to SML, index 3, I get the logentry "tele/Zaehler/SENSOR#SML='watt':150}"

[Ath]

Totally untested, but can you set the attribute to SML.Watt ?

[Wiki]

Yes, I've tried almost every configuration with seperation signs, nothing worked.

I've solved the Problem (for me) with a small python script on my 24/7 Raspberry:

Code: Select all

# python 3.8.10

import random
import json

from paho.mqtt import client as mqtt_client

broker = '192.168.xxx.yyy'
port = 1883
topic = "Zaehler/SENSOR"
client_id = f'python-mqtt-{random.randint(0, 100)}'

def connect_mqtt() -> mqtt_client:
    def on_connect(client, userdata, flags, rc):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)

    client = mqtt_client.Client(client_id)
    client.on_connect = on_connect
    client.connect(broker, port)
    return client

    def subscribe(client: mqtt_client):
        def on_message(client, userdata, msg):
            data=json.loads(msg.payload)
            result = client.publish('Zaehler/SENSOR/Watt',data['SML']['Watt'])
            status = result[0]

    client.subscribe(topic)
    client.on_message = on_message

def run():
    client = connect_mqtt()
    subscribe(client)
    client.loop_forever()

if __name__ == '__main__':
    run()

So I get a clear payload on the topic "Zaehler/SENSOR/Watt" and therefore no problem with importing the data into my tiny little ESP32 and its MQTT Import.

But I would prefer a solution integrated in ESPEasy.

[Ath]

I may have a quick solution for this dual-level JSON data issue, what exact ESP32 build do you use?, so I can provide you with a testbuild .

Edit:
Just for fun, I've already compiled an ESP32 Normal build:

ESP_Easy_mega_20221114_normal_ESP32_4M316k.zip

(1.72 MiB) Downloaded 96 times

You can now use the SML.Watt format for the JSON attribute. Only 1 sub-level supported!

[Wiki]

Oh man. Sometimes I'm asking me if you (additionally: TD-er) are doing anything else than supporting ESPEasy.

Your fix works, Thanks a lot.

[TD-er]

Oh man. Sometimes I'm asking me if you (additionally: TD-er) are doing anything else than supporting ESPEasy.
[...]

What do you think ...

[Ath]

I've created a pull request #4363 for this feature request, and also tossed in some minor string and memory optimizations.