New hook octoprint.comm.protocol.temperatures.received

Allows preprocessing/sanitizing temperatures as received from the
printer.

Workaround for printers that occasionally report garbage temperature
data, e.g. #2050

docs/plugins/hooks.rst

@@ -555,6 +555,32 @@ octoprint.comm.protocol.scripts
    :return: A 2-tuple in the form ``(prefix, postfix)`` or None
    :rtype: tuple or None
 
+.. _sec-plugins-hook-comm-protocol-temperatures-received:
+
+octoprint.comm.protocol.temperatures.received
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. py:function:: protocol_temperatures_received_hook(comm_instance, parsed_temperatures, *args, **kwargs)
+
+   Get the parsed temperatures returned by the printer, allowing handlers to modify them prior to handing them off
+   to the system. Handlers are expected to either return ``parsed_temperatures`` as-is or a modified copy thereof.
+
+   ``parsed_temperatures`` is a dictionary mapping from tool/bed identifier (``B``, ``T0``, ``T1``) to a 2-tuple of
+   actual and target temperature, e.g. ``{'B': (45.2, 50.0), 'T0': (178.9, 210.0), 'T1': (21.3, 0.0)}``.
+
+   This hook can be useful in cases where a printer e.g. is prone to returning garbage data from time to time, allowing
+   additional sanity checking to be applied and invalid values to be filtered out. If a handler returns an empty
+   dictionary or ``None``, no further processing will take place.
+
+   **Example**
+
+   The following example shows how to filter out actual temperatures that are outside a sane range of 1°C to 300°C.
+
+   .. onlineinclude:: https://raw.githubusercontent.com/OctoPrint/Plugin-Examples/master/sanitize_temperatures.py
+      :linenos:
+      :tab-width: 4
+      :caption: `sanitize_temperatures.py <https://github.com/OctoPrint/Plugin-Examples/blob/master/sanitize_temperatures.py>`_
+
 .. _sec-plugins-hook-comm-transport-serial-factory:
 
 octoprint.comm.transport.serial.factory

src/octoprint/util/comm.py

@@ -441,6 +441,8 @@ class MachineCom(object):
 		self._gcodescript_hooks = self._pluginManager.get_hooks("octoprint.comm.protocol.scripts")
 		self._serial_factory_hooks = self._pluginManager.get_hooks("octoprint.comm.transport.serial.factory")
 
+		self._temperature_hooks = self._pluginManager.get_hooks("octoprint.comm.protocol.temperatures.received")
+
 		# SD status data
 		self._sdEnabled = settings().getBoolean(["feature", "sdSupport"])
 		self._sdAvailable = False
@@ -1129,6 +1131,14 @@ class MachineCom(object):
 		current_tool = self._currentTool if self._currentTool is not None else 0
 		maxToolNum, parsedTemps = parse_temperature_line(line, current_tool)
 
+		for name, hook in self._temperature_hooks.items():
+			try:
+				parsedTemps = hook(self, parsedTemps)
+				if parsedTemps is None or not parsedTemps:
+					return
+			except:
+				self._logger.exception("Error while processing temperatures in {}, skipping".format(name))
+
 		if "T0" in parsedTemps.keys():
 			for n in range(maxToolNum + 1):
 				tool = "T%d" % n