Separate out different messages

[garthpaine]

I want to know when I get a LoRA Join message rather than other data packets - so for instance the following is a join message - I want to separate out these from other messages - but trying to look for instance ---

if (msg.payload.join_accept.session_key_id){
                   // do nothing 
 } else if (msg.payload.uplink_message.decoded_payload.Cert > 0){

does not work as the msg.payload.join_accept.session_key_id does not exist in other messages - would love some thoughts - thanks, Garth

{"end_device_ids":{"device_id":"18-audio","application_ids":{"application_id":"costa-rica-development"},"dev_eui":"xxxxxxxxxx","join_eui":"xxxxxxx","dev_addr":"xxxxxxx"},"correlation_ids":["as:up:xxxxxxxx","gs:conn:xxxxxxx","gs:up:host:xxxxxxxk:xxxxxxx","ns:uplink:xxxxxxx","rpc:/ttn.lorawan.v3.GsNs/HandleUplink:xxxxxxx","rpc:/ttn.lorawan.v3.NsAs/HandleUplink:xxxxxxx"],"received_at":"2023-09-18T19:04:27.003981894Z","join_accept":{"session_key_id":"xxxxxxxxxx==","received_at":"2023-09-18T19:04:xxxxxxxx'

---

Admin edit: wrap code in backticks

[Steve-Mcl]

You can use a switch mode to direct messages by adding 2 entries

1. Has key : msg.payload.join_accept.session_key_id
2. Otherwise

Then you don't need to worry about testing for the existence of the key at all

[garthpaine]

Thanks so much Steve

how do you recommend implementing this as an if statement throws an error if that part of the payload is not present - indeed a Switch statement would be a great approach

[garthpaine]

actually I got it - thanks Genius!!

[garthpaine]

OK I'm back

so this works msg.payload.join_accept and catches all Join requests which is great
However if I try

1. Has key : uplink_message.decoded_payload.Cert

I do not get a match, even though this exists in the alternative uploaded message.
Any advice would be welcome - thanks

[Colin]

Show us the incoming message copied from the debug pane using Copy Value in the debug pane, and also screenshot of how you have setup the Switch node.