Hi all, I have a number of mqtt topic subscriptions in my flow that I push to a dashboard. [image] Now, I want to replace ${QWKID} and ${BBSHOST} with flow variables. I setup a function to configure two flow variables, QWKID and BBSHOST [image] Now the question I have is, how do I connect in …

If you are running the latest node-red you can use dynamic subscriptions in the mqtt in node. there is a dropdown in the node config to select this option. There is help text in the sidebar that describes the properties you need to send it. Have a go and feel free to ask if you get any issues.

That's nice, but I'm using mqtt in, not mqtt out.

I see that mqtt in also has dynamic subscriptions but I'm not sure how that really helps me. It doesn't explain much in the help.

That was a typo i meant in. It explains it very clearly in the help you need to send msg.action of "subscribe" or "unsubscribe" and the msg.topic containing the topic you wish to subscribe or unsubscribe to. An example [{"id":"8f199f8fc9b6248b","type":"inject","z":"da8a6ef0b3c9a5c8","name":"subs…

[image] nelgin: It does seem to highlight that a better way (easy) was on using flow variables in a topic could be devised though. The problem with using flow variables is: what does the MQTT node do when you change the flow variable? does it unsubscribe the old topic and subscribe the new to…

[image] nelgin: Your method does look like complete overkill for what I need. I have no way of knowing your needs. I answered your question [image] nelgin: Now the question I have is, how do I connect in the function or get the variables to be assigned and then how do I use them in the m…

Using flow variables in an mqtt topic

General

nelgin 15 December 2022 09:40 6

I just went with the lazy and highly portable method of using sbbs/+/+/whatever...

Your method does look like complete overkill for what I need.

It does seem to highlight that a better way (easy) was on using flow variables in a topic could be devised though.

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Using flow variables in an mqtt topic

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