Hoping someone can help me. I am trying to pull sensor information from a device (MQTT), but having trouble extracting just what I need from the payload.
Debug output looks like this:
7/13/2022, 10:24:01 AM node: 0c1ee5723f948408meraki/v1/mt/L_585467951558182753/ble/{DeviceMAC}/temperature : msg : Object
When I go to extract "fahrenheit":75.5, I try to do it like this:
msg.payload[1] but that only seems to get me """, msg.payload[2] is "t", msg.payload[3] is "s", so it seems that the payload is not an actual array, it seems to be reading it as a string?. Does that make sense?
Any ideas how I can extract any of those 3 values? (timestamp, F, C)
In this case msg.payload is an object (objects are surrounded by curly braces {}), not an array (arrays are surrounded by brackets []). You can access them like msg.payload.ts or msg.payload.fahrenheit rather than msg.payload[X]
msg.payload could also be a JSON string, in which case you would need to convert it into an object first.
There’s a great page in the docs (Working with messages : Node-RED) that will explain how to use the debug panel to find the right path to any data item.
Pay particular attention to the part about the buttons that appear under your mouse pointer when you over hover a debug message property in the sidebar.
Are you outputting an object from the mqtt node? If not select output a parse object in the mqtt node config.
Then fahrenheit will be an object property, You will then access it at msg.payload.fahrenheit
Great callout! Didnt even think to look at what my mqtt node was configured as, it was set to automatic (string or buffer)
I changed it to JSON object, and now I can call on it using msg.payload.fahrenheit
Thank you all for your help and guidance! As you can tell, I am a newbie, but love learning new things
