Can OctoPrint settings ever be empty? (Regarding global_get)

stringsonfire · June 7, 2020, 1:50pm

In this case, I'm checking ["serial","port"], but in general I'd like to always handle the empty case, if any, when using global_get() to get OctoPrint settings.

What happens if I try to get an OctoPrint setting using correct path, but nothing is set yet? Is this even possible?

I've checked here but it's not documented (unless i've missed it):
https://docs.octoprint.org/en/master/modules/plugin.html?highlight=global_get#octoprint.plugin.PluginSettings.global_get
https://docs.octoprint.org/en/master/modules/settings.html#octoprint.settings.Settings

jneilliii · June 7, 2020, 2:46pm

My assumption would be that it returns a NoneType or raises an error. Typically when the docs don't give you the answer I go to the source...this is what global_get forwards your request to.

github.com

OctoPrint/OctoPrint/blob/a9340754074554553bacf3e865819baaa52f28ce/src/octoprint/settings.py#L1506


	def has(self, path, **kwargs):
		try:
			self._get_value(path, **kwargs)
		except NoSuchSettingsPath:
			return False
		else:
			return True

	#~~ getter

	def get(self, path, **kwargs):
		error_on_path = kwargs.pop("error_on_path", False)
		validator = kwargs.pop("validator", None)
		fallback = kwargs.pop("fallback", None)

		def process():
			try:
				return self._get_value(path, **kwargs)
			except NoSuchSettingsPath:
				if error_on_path:
					raise

stringsonfire · June 7, 2020, 3:34pm

Thanks, will stick with checking it's not None then

jneilliii · June 7, 2020, 10:12pm

I'm not one hundred percent sure, because it looks like it raises an error, so you'd have to detect in try/except block for the error raised.