# Insert a mqtt tree ( directories? )
**URL:** https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385
**Category:** General
**Tags:** home-assistant
**Created:** [7 August 2023 17:47 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385 "2023-08-07T17:47:03Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@plekke](https://discourse.nodered.org/u/plekke)
#### Post date: [7 August 2023 17:47 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/1 "2023-08-07T17:47:03Z")
hello ,
i'm learning nodered and mqtt.
i use also homeassistant , and when i create an esp32node with mqtt enabled , then i got a very nice tree-structure in mqtt-explorer
now i want to create some data to send to my mqtt broker , but as test i want to inject some hardcoded values to my broker.
but it need to have a nice tree-strucure like in this image above.
my first test is complete differtent result in mqtt-explorer :
how can i create a kind of directory and subdirectorries ?
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### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [7 August 2023 17:52 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/2 "2023-08-07T17:52:39Z")
The 'tree' structure is just the parts of the topic in the msg being published. The topic. is broken into levels with a slash `/`.
You should spend some time and read thru this tutorial [MQTT Essentials - All Core Concepts explained](https://www.hivemq.com/mqtt-essentials/)
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### Author:  [@plekke](https://discourse.nodered.org/u/plekke)
#### Post date: [7 August 2023 18:07 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/3 "2023-08-07T18:07:50Z")
is there no easy flow to generate a mqtt wit a 'directory structure with values ' with 1inject node ?
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### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [7 August 2023 18:20 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/4 "2023-08-07T18:20:32Z")
It is very easy to create a topic in a msg with various levels for example setting msg.topic to:
`home/firstFloor/livingroom/northwall/switch`
but really you should go read the tutorial, it examines a lot and has a complete section on topics and hoe to subscribe to them. It will be worth your time to learn the terminology and get an understanding of how the pub/sub process works.
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### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [7 August 2023 20:17 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/5 "2023-08-07T20:17:41Z")
I like to reproduce internal JSON structures to equivalent trees in MQTT. The best way is to create a function node that walks through the JSON input and outputs the topic/value pairs. Done right, you only need to do it once and then you should be able to reuse it.
I guess I should probably write a node for that at some point unless someone has beaten me to it.
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [7 August 2023 20:35 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/6 "2023-08-07T20:35:46Z")
> [@plekke](#):
>
> is there no easy flow to generate a mqtt wit a 'directory structure with values ' with 1inject node ?
As a matter of interest, why do you want to do this? Under what circumstances?
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### Author:  [@plekke](https://discourse.nodered.org/u/plekke)
#### Post date: [7 August 2023 20:48 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/7 "2023-08-07T20:48:47Z")
i want to send a simple hardcode big mqtt structure , so i can test my recievers and other flows.
just a matter to inject something to "debug/unit tes"t my recieving flows
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [7 August 2023 20:57 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/8 "2023-08-07T20:57:00Z")
OK, good reason. In a function node you can do something like
```auto
node.send({topic: "a/b/c1", payload: "somevalue"})
node.send({topic: "a/b/c2", payload: "someothervalue"})
etc.
```
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### Author:  [@plekke](https://discourse.nodered.org/u/plekke)
#### Post date: [8 August 2023 15:34 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/9 "2023-08-08T15:34:02Z")
thank u Colin
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [22 August 2023 15:34 UTC](https://discourse.nodered.org/t/insert-a-mqtt-tree-directories/80385/10 "2023-08-22T15:34:21Z")
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