I've done a decent amount of research on this but haven't quite found exactly what I'm looking for yet. I'll preface by saying that the first half of this question is more of a pi-specific question and not necessarily just a NodeRED question, but I wanting to include it for context for my second, NodeRED-specific, question.
I'm working on a solution using NodeRED on a pi where the pi will first connect to a non-internet facing network via ethernet. I'd like the user to then be able to set their Wifi settings by accessing the Pi via a webserver on that closed LAN.
The idea being that the ethernet connection will stay non-internet facing, but the wifi will connect to the internet, and that wifi SSID/PW could change from day to day at different sites.
Most of the solutions I've found so far involve making the Pi a wifi hotspot to connect to first, in IoT style applications.
As an alternate, I'm currently setting various configuration options in my solution using a JSON file that NodeRED is reading. I'd be potentially open to using that same JSON to include SSID/PW information, but then would need a little guidance on how to use NodeRED to appropriately update that information in the wpa_supplicant file.