From 5b9c54748eefe9769b9f628968470cd6115ad9f5 Mon Sep 17 00:00:00 2001
From: Fabio Manganiello <blacklight86@gmail.com>
Date: Wed, 2 Jan 2019 09:29:27 +0100
Subject: [PATCH] Do not propagate a null response message back to the bus to
 prevent backends from breaking

---
 platypush/backend/mqtt.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/platypush/backend/mqtt.py b/platypush/backend/mqtt.py
index c4f361e65..ea5638517 100644
--- a/platypush/backend/mqtt.py
+++ b/platypush/backend/mqtt.py
@@ -98,6 +98,8 @@ class MqttBackend(Backend):
         def on_message(client, userdata, msg):
             def response_thread(msg):
                 response = self.get_message_response(msg)
+                if not response:
+                    return
                 response_topic = '{}/responses/{}'.format(self.topic, msg.id)
 
                 self.logger.info('Processing response on the MQTT topic {}: {}'.