Prevent ExtensionServer.get_controller keyerror, and try to put in a …

…more helpful error (real error still not fixed)

ulauncher/api/server/ExtensionServer.py

@@ -73,7 +73,7 @@ def get_controller(self, extension_id):
         :param str extension_id:
         :rtype: ~ulauncher.api.server.ExtensionController.ExtensionController
         """
-        return self.controllers[extension_id]
+        return self.controllers.get(extension_id)
 
     def get_controllers(self):
         """

ulauncher/ui/windows/PreferencesUlauncherDialog.py

@@ -454,6 +454,9 @@ def prefs_extension_update_prefs(self, url_params):
         logger.info('Update extension preferences: %s', query)
         prefix = 'pref.'
         controller = ExtensionServer.get_instance().get_controller(ext_id)
+        if not controller:
+            logger.error("Cannot update preferences. The extension controller is not registered. Try relaunching or restarting Ulauncher")
+            return
         preferences = [(key[len(prefix):], value) for key, value in query.items() if key.startswith(prefix)]
         for pref_id, value in preferences:
             old_value = controller.preferences.get(pref_id)['value']
@@ -516,11 +519,7 @@ def _get_all_extensions(self) -> List[ExtensionInfo]:
 
     def _get_extension_info(self, ext_id: str, prefs: ExtensionPreferences, error: ExtError = None) -> ExtensionInfo:
         ext_db = ExtensionDb.get_instance()
-        is_connected = True
-        try:
-            ExtensionServer.get_instance().get_controller(ext_id)
-        except KeyError:
-            is_connected = False
+        is_connected = bool(ExtensionServer.get_instance().get_controller(ext_id))
         ext_runner = ExtensionRunner.get_instance()
         is_running = is_connected or ext_runner.is_running(ext_id)
         ext_db_record = ext_db.find(ext_id, {})