From cba4791b65b67fda80bba192fef766e1957b76cf Mon Sep 17 00:00:00 2001
From: Dave C-J <conway@uk.ibm.com>
Date: Mon, 8 Sep 2014 20:19:25 +0100
Subject: [PATCH] MQTT node better check for topic existing

---
 nodes/core/io/10-mqtt.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nodes/core/io/10-mqtt.js b/nodes/core/io/10-mqtt.js
index 90636500b..267a5368a 100644
--- a/nodes/core/io/10-mqtt.js
+++ b/nodes/core/io/10-mqtt.js
@@ -95,7 +95,7 @@ module.exports = function(RED) {
                     if (node.topic) {
                         msg.topic = node.topic;
                     }
-                    if (typeof msg.topic === "string") { // topic must be a string
+                    if ((msg.hasOwnProperty("topic")) && (typeof msg.topic === "string") && (msg.topic !== "")) { // topic must exist
                         this.client.publish(msg);  // send the message
                     }
                     else { node.warn("Invalid topic specified"); }