I just got Klipper going on my Octoprint, and one thing about it I like is the "virtual SD card", which bypasses the Klipper to Octoprint to Control Card communication, which speeds things up. One thing about it that I don't like, though I understand it, is that I can't do a "Preheat". Either Octoprint ot Preheat Button gives an error that basically says it can't get the temperature from the SD card. It's too bad, because as it is, printing from the virtual SD card is faster again, and eliminates "stuttering".
I wonder, is there a way for your plugin to recognize that the SD card is actually a virtual one, and somehow grab the temperature out of it for a preheat?