Load json for mqtt callbacks

mqtt_sensord/sensorlib/base.py

@@ -1,3 +1,9 @@
+try:
+    import json
+except ImportError:
+    import ujson as json
+
+
 def sensor(cls):
     Sensor.register(cls)
 
@@ -60,6 +66,11 @@ class Sensor(object):
 
     @classmethod
     def run_mqtt_callback(cls, mqtt_topic, data):
+        try:
+            data = json.loads(data)
+        except ValueError:
+            print("Could not parse data {}".format(data))
+
         if mqtt_topic in cls._mqtt_callbacks:
             cls._mqtt_callbacks[mqtt_topic](data)
         else: