Fix message unpacking for commander

DecisionSystem/CentralisedDecision/commander.py

@@ -60,7 +60,12 @@ class Commander:
         self.make_decision()
 
     def on_message(self, client, userdata, message):
-        messageDict = umsgpack.unpackb()
+        try:
+            messageDict = umsgpack.unpackb(message.payload)
+        except:
+            print("Incorrect Message")
+            return
+
         if "type" in messageDict.keys:
             # Need to consider that a malicious message may have a type with incorrect subtypes. 
             if messageDict["type"] == "connect":