using and parsing JSON objects msg.payload

[Don Biederman]

Hi

I'm using a NodeMcu to monitor a few sump pumps at my home sending this using MQTT. The I'm using the topic of "home/sump_pump" I'm  publishing the following JSON data to the broker as:

{"level":"normal","dcpwr":"ok","acpwr":"ok","run":"stop"} . 

My question how do I parse the msg.payload to retrieve the values of the 4 sensor in Node-Red and display the status and send and email once if level = "high"? 

Thank you

Don Biederman 

[Dave C-J]

Data received from an MQTT node is typically in String format - wheras we need JSON to be able to parse it easily.. - so feed the output of teh MQTT node into a JSON node... then you can get to your properties in either a function node or switch node or... whatever.

They should be then available as   msg.payload.level   msg.payload.run  etc...

[Brian Orpin]

Try this;

[{"id":"bc3f9e17.11af4","type":"inject","z":"4590d4a5.b2b604","name":"","topic":"","payload":"{\"level\":\"normal\",\"dcpwr\":\"ok\",\"acpwr\":\"ok\",\"run\":\"stop\"}","payloadType":"str","repeat":"","crontab":"","once":false,"x":218,"y":133,"wires":[["85ffbdca.b8f52"]]},{"id":"85ffbdca.b8f52","type":"json","z":"4590d4a5.b2b604","name":"","x":366,"y":133,"wires":[["8ee5ac04.0282b","c5706cf6.067f2"]]},{"id":"8ee5ac04.0282b","type":"debug","z":"4590d4a5.b2b604","name":"","active":true,"console":"false","complete":"false","x":516,"y":132,"wires":[]},{"id":"c5706cf6.067f2","type":"debug","z":"4590d4a5.b2b604","name":"","active":true,"console":"false","complete":"payload.level","x":528,"y":183,"wires":[]}]

[Don Biederman]

thanks so much that helps out so much! I didnt have a JSON node and was getting undefined error in debug.  I'm learning about this love how Node-Red works I want to make a UI and have it email me. Can you give a lead on how to keep it from emailing me each time it receives a message. Say email me when "level" = "high" and email me once again when it returns back to "normal".  

[Don Biederman]

thank I see msg.payload.acpwr will give me the value.

[Dave C-J]

look at the rbe node...

[Brian Orpin]

And now I learn something as well. Excellent.

On Sunday, 26 March 2017 17:40:46 UTC+1, Dave C-J wrote:

look at the rbe node...