More work on slicing integration:

- be able to handle slicers which can't report progress
- distinguish between registered and configured slicers (e.g. to allow uploading of profiles via the settings before having saved the path to the executable)

docs/events/index.rst

@@ -328,6 +328,7 @@ SlicingStarted
 
      * ``stl``: the STL's filename
      * ``gcode``: the sliced GCODE's filename
+     * ``progressAvailable``: true if progress information via the ``slicingProgress`` push update will be available, false if not
 
 SlicingDone
    The slicing of a file has completed.

src/octoprint/plugin/types.py

@@ -199,6 +199,7 @@ class SlicerPlugin(Plugin):
 			type=None,
 			name=None,
 			same_device=True,
+			progress_report=False
 		)
 
 	def get_slicer_profile_options(self):

src/octoprint/plugins/cura/__init__.py

@@ -194,7 +194,8 @@ class CuraPlugin(octoprint.plugin.SlicerPlugin,
 		return dict(
 			type="cura",
 			name="CuraEngine",
-			same_device=True
+			same_device=True,
+			progress_report=True
 		)
 
 	def get_slicer_default_profile(self):

src/octoprint/slicing/__init__.py

@@ -73,22 +73,26 @@ class SlicingManager(object):
 
 	@property
 	def slicing_enabled(self):
-		return len(self.registered_slicers) > 0
+		return len(self.configured_slicers) > 0
 
 	@property
 	def registered_slicers(self):
 		return self._slicers.keys()
 
+	@property
+	def configured_slicers(self):
+		return map(lambda slicer: slicer.get_slicer_properties()["type"], filter(lambda slicer: slicer.is_slicer_configured(), self._slicers.values()))
+
 	@property
 	def default_slicer(self):
 		slicer_name = settings().get(["slicing", "defaultSlicer"])
-		if slicer_name in self.registered_slicers:
+		if slicer_name in self.configured_slicers:
 			return slicer_name
 		else:
 			return None
 
-	def get_slicer(self, slicer):
-		return self._slicers[slicer] if slicer in self._slicers else None
+	def get_slicer(self, slicer, require_configured=True):
+		return self._slicers[slicer] if slicer in self._slicers and (not require_configured or self._slicers[slicer].is_slicer_configured()) else None
 
 	def slice(self, slicer_name, source_path, dest_path, profile_name, callback, callback_args=None, callback_kwargs=None, overrides=None, on_progress=None, on_progress_args=None, on_progress_kwargs=None):
 		if callback_args is None:
@@ -96,8 +100,11 @@ class SlicingManager(object):
 		if callback_kwargs is None:
 			callback_kwargs = dict()
 
-		if not slicer_name in self.registered_slicers:
-			error = "No such slicer: {slicer_name}".format(**locals())
+		if not slicer_name in self.configured_slicers:
+			if not slicer_name in self.registered_slicers:
+				error = "No such slicer: {slicer_name}".format(**locals())
+			else:
+				error = "Slicer not configured: {slicer_name}".format(**locals())
 			callback_kwargs.update(dict(_error=error))
 			callback(*callback_args, **callback_kwargs)
 			return False, error

src/octoprint/static/js/app/dataupdater.js

@@ -181,7 +181,11 @@ function DataUpdater(allViewModels) {
                     } else if (type == "SlicingStarted") {
                         gcodeUploadProgress.addClass("progress-striped").addClass("active");
                         gcodeUploadProgressBar.css("width", "100%");
-                        gcodeUploadProgressBar.text(_.sprintf(gettext("Slicing ... (%(percentage)d%%)"), {percentage: 0}));
+                        if (payload.progressAvailable) {
+                            gcodeUploadProgressBar.text(_.sprintf(gettext("Slicing ... (%(percentage)d%%)"), {percentage: 0}));
+                        } else {
+                            gcodeUploadProgressBar.text(gettext("Slicing ..."));
+                        }
                     } else if (type == "SlicingDone") {
                         gcodeUploadProgress.removeClass("progress-striped").removeClass("active");
                         gcodeUploadProgressBar.css("width", "0%");