Powerstrip fixes (#121)

* Fix invalid JSON as delivered by powerstrip's info() when it has no cloud connectivity

* wrap mode to avoid crashing on None, use __repr__ instead of __str__

miio/powerstrip.py

@@ -47,11 +47,13 @@ def load_power(self) -> Optional[float]:
         return None
 
     @property
-    def mode(self) -> PowerMode:
+    def mode(self) -> Optional[PowerMode]:
         """Current operation mode, can be either green or normal."""
-        return PowerMode(self.data["mode"])
+        if self.data["mode"] is not None:
+            return PowerMode(self.data["mode"])
+        return None
 
-    def __str__(self) -> str:
+    def __repr__(self) -> str:
         s = "<PowerStripStatus power=%s, temperature=%s, " \
             "load_power=%s mode=%s>" % \
             (self.power,

miio/protocol.py

@@ -167,16 +167,20 @@ def _decode(self, obj, context):
             decrypted = Utils.decrypt(obj, context['_']['token'])
             decrypted = decrypted.rstrip(b"\x00")
         except Exception:
-            _LOGGER.debug("Unable to decrypt, returning raw bytes.")
+            _LOGGER.debug("Unable to decrypt, returning raw bytes: %s", obj)
             return obj
 
+        decoded = decrypted.decode('utf-8')
         try:
-            jsoned = json.loads(decrypted.decode('utf-8'))
+            return json.loads(decoded)
         except:
-            _LOGGER.error("unable to parse json, was: %s", decrypted)
-            raise
-
-        return jsoned
+            try:
+                # powerstrip returns invalid JSON if the device is not
+                # connected to the cloud, so we try to fix it here carefully.
+                decoded = decoded.replace(',,"otu_stat"', ',"otu_stat"')
+                return json.loads(decoded)
+            except Exception as ex:
+                _LOGGER.error("unable to parse json '%s': %s", decoded, ex)
 
 
 Message = Struct(