Hmmm... interesting. So I can create an http node that can receive a local trigger, like curl http://localhost...? That would work. I'll look into that.
My intent is to use it from the homebridge-commander plugin for homebridge. I set up homebridge a good while before I started playing with node red. I've got a handful of plugins and a little over a dozen devices set up in it (RF outlets, WeMo Devices, a garage door, my TV, etc.). It's a little buggy. Sometimes I have to issue commands twice. Sometimes the command succeeds but Siri thinks it failed.
I looked into trying to have my homebridge(/home app) devices show up in node red, but apparently you can only create devices in node red and can't issue commands to devices that the home app already is aware of. I guess that makes sense now that I understand better how it all works.
Perhaps at some point, setting up the devices anew in node red using a homekit node would be worthwhile. It might work better than homebridge (but I think they're both built on the same HAP-nodejs thing - so perhaps not). The limitation of homebridge is that I cannot control its devices remotely without exposing the pi to the internet to some degree, nor can you use any sort of autonomous triggering, which is why I've started playing with node red and webhook relay. Even if I did set up a homekit node, the remaining limitation might be that I cannot use Siri to trigger actions remotely... unless again, I expose the RPi to the internet.
But being able to trigger flows from the command line (or rather, the homebridge-commander plugin) was the low-hanging fruit option I was exploring for being able to use Siri to switch "OSs" on the RPi.
