refactor format mqtt format parser

homeassistant/components/mqtt/__init__.py

@@ -129,13 +129,24 @@ def setup(hass, config):
     return True
 
 
-class JsonFmtParser(object):
-  """ Implements a json parser on xpath"""
-  def __init__(self, jsonpath):
-    self._expr = jsonpath_rw.parse(jsonpath)
+class FmtParser(object):
+  """ wrapper for all supported formats """
+  
+  class _JsonFmtParser(object):
+    """ Implements a json parser on xpath"""
+    def __init__(self, jsonpath):
+      self._expr = jsonpath_rw.parse(jsonpath)
+    def __call__(self, payload):
+      match = self._expr.find(json.loads(payload))
+      return match[0].value if len(match) > 0 else None 
+      
+  def __init__(self, fmt):
+    if fmt.startswith('json:'):
+      self._parser = FmtParser._JsonFmtParser(fmt[5:])
+    else:
+      self._parser = lambda x: x
   def __call__(self, payload):
-    match = self._expr.find(json.loads(payload))
-    return match[0].value if len(match) > 0 else None
+    return self._parser(payload)
 
 
 # This is based on one of the paho-mqtt examples:

homeassistant/components/sensor/mqtt.py

@@ -47,12 +47,7 @@ class MqttSensor(Entity):
         self._state_topic = state_topic
         self._qos = qos
         self._unit_of_measurement = unit_of_measurement
-        self._state_format = state_format
-        
-        if self._state_format.startswith('json:'):
-          self._parser = mqtt.JsonFmtParser(self._state_format[5:])
-        else:
-          self._parser = lambda x: x
+        self._parser = mqtt.FmtParser(state_format)
 
         def message_received(topic, payload, qos):
             """ A new MQTT message has been received. """

homeassistant/components/switch/mqtt.py

@@ -55,13 +55,7 @@ class MqttSwitch(SwitchDevice):
         self._payload_on = payload_on
         self._payload_off = payload_off
         self._optimistic = optimistic
-        
-        self._state_format = state_format
-        
-        if self._state_format.startswith('json:'):
-          self._parser = mqtt.JsonFmtParser(self._state_format[5:])
-        else:
-          self._parser = lambda x: x
+        self._parser = mqtt.FmtParser(state_format)
 
         def message_received(topic, payload, qos):
             """ A new MQTT message has been received. """