# Message packages not working as I thought. MQTT
**URL:** https://discourse.nodered.org/t/message-packages-not-working-as-i-thought-mqtt/14903
**Category:** General
**Created:** [29 August 2019 12:34 UTC](https://discourse.nodered.org/t/message-packages-not-working-as-i-thought-mqtt/14903 "2019-08-29T12:34:20Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [29 August 2019 12:34 UTC](https://discourse.nodered.org/t/message-packages-not-working-as-i-thought-mqtt/14903/1 "2019-08-29T12:34:20Z")
I am sending a message via MQTT and things aren't working as I thought.
This is an example message I am sending:
```auto
{"topic":"COMMAND_REPLY/BedPi","payload":{"payload":"Command fail","device":"COMMAND_REPLY/BedPi"},"qos":2,"retain":false,"_msgid":"51f5a1cc.a1fe4","_event":"node:1f11accb.bee033"}
```
That goes into a MQTT OUT node.
Arriving at the other end, things fall apart.
I put it through a `JSON` node then a `CHANGE` node to get back the data I want.
Receiving flow: (With test input)
```auto
[{"id":"ea3e72bc.093a6","type":"json","z":"9c1e5490.5d70b","name":"","property":"payload","action":"","pretty":false,"x":370,"y":160,"wires":[["4b2aa5e5.87520c","8e791548.a30768"]]},{"id":"2ffdc757.4feef8","type":"mqtt in","z":"9c1e5490.5d70b","name":"Urgent alarms","topic":"ALARM/A1","qos":"2","datatype":"auto","broker":"8a2e80be.f7c928","x":210,"y":160,"wires":[["fa75dbc1.464fc","ea3e72bc.093a6"]]},{"id":"4b2aa5e5.87520c","type":"debug","z":"9c1e5490.5d70b","name":"A1 alarm After JSON","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":610,"y":110,"wires":[]},{"id":"8e791548.a30768","type":"change","z":"9c1e5490.5d70b","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"payload.payload","tot":"msg"},{"t":"set","p":"device","pt":"msg","to":"payload.device","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":530,"y":160,"wires":[["e4c7245a.ee0d08"]]},{"id":"fa75dbc1.464fc","type":"debug","z":"9c1e5490.5d70b","name":"RAW A1 alarm","active":false,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":390,"y":110,"wires":[]},{"id":"e4c7245a.ee0d08","type":"debug","z":"9c1e5490.5d70b","name":"Message","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":720,"y":160,"wires":[]},{"id":"24de9be5.20338c","type":"function","z":"9c1e5490.5d70b","name":"","func":"msg.payload = {\n \"topic\":\"ALARM/A1\",\"payload\":{\"payload\":\"Command fail\",\"device\":\"COMMAND_REPLY/BedPi\"},\n \n}\nreturn msg;","outputs":1,"noerr":0,"x":240,"y":240,"wires":[["8e791548.a30768"]]},{"id":"8cac197f.7078b","type":"inject","z":"9c1e5490.5d70b","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":90,"y":240,"wires":[["24de9be5.20338c"]]},{"id":"8a2e80be.f7c928","type":"mqtt-broker","z":"","name":"MQTT host","broker":"192.168.0.99","port":"1883","clientid":"","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"birthTopic":"ARDUINO_STATUS","birthQos":"2","birthPayload":"connected","willTopic":"ARDUINO_STATUS","willQos":"0","willPayload":"disconnected"}]
```
My take:
This message is seen in the `A1 after JSON` debug node:
```auto
{"topic":"ALARM/A1","payload":{"payload":"Command fail","device":"COMMAND_REPLY/BedPi"},"qos":2,"retain":false,"_msgid":"86a0f848.bae808"}
```
Looks good.
It has the payload thingy built/existing/visible.
I then put it through the `CHANGE` node and set `msg.device` to `msg.payload.device`.
Nothing.
But if I press the `inject` button, it works and I get a `msg.payload` and `msg.device` at the end debug node.
Yeah, I am missing something obvious. Alas that's where I am at.
I'll keep trying to work out what I am not seeing, but help would be appreciated.
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [29 August 2019 12:40 UTC](https://discourse.nodered.org/t/message-packages-not-working-as-i-thought-mqtt/14903/2 "2019-08-29T12:40:18Z")
I'm stupid.
FAULT DISCOVERED!
The `CHANGE` node!
I set the `msg.payload` before I set the `msg.device`.
So when I look to set the `msg.device` (second change), there is nothing there because I just changed the `msg.payload`.
Be this a lesson for new people.
If messing around with the `CHANGE` node:
**Modify the `msg.payload` LAST!**