Increment a state variable in payload format Converter

[iot-payload]

Hi guys,
I’ve need a increment variable in function Convert(decoded, port), is possible?
Actually at every access is resetting…

Thanks a lot
Stefano

[arjanvanb (Arjan)]

Not possible; you only get the decoded application payload and the port number, and cannot preserve any state. It’s also not possible in the Decoder function.

See also:

• Access to previous data in Payload format
• How can i do a condition using two uplink messages?
• Access Metadata in decoder
• Payload Formats [HowTo] - #3 by arjanvanb

So, you’ll need to keep state on your application server, or use some third-party server. For Node-RED see Working with context. For Pipedream, see $checkpoint in Workflow state.

And beware:

@johan

We’re dropping the converter and validator in V3 as they’re not being used; you can put conversion in the decoder, and it makes more sense to drop/filter out invalid values higher upstream.