From f36ec4cf85a84d094c6b779b33004d5443e13184 Mon Sep 17 00:00:00 2001
From: Malachi Burke <malachi.burke@gmail.com>
Date: Mon, 14 Dec 2015 20:10:00 -0800
Subject: [PATCH] Fixing reversal of topic/packet identifier (topic should come
 first)

---
 Adafruit_MQTT.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Adafruit_MQTT.cpp b/Adafruit_MQTT.cpp
index 9cb0898..8d6beda 100644
--- a/Adafruit_MQTT.cpp
+++ b/Adafruit_MQTT.cpp
@@ -490,6 +490,7 @@ uint8_t Adafruit_MQTT::connectPacket(uint8_t *packet) {
   return len;
 }
 
+// as per http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718040
 uint8_t Adafruit_MQTT::publishPacket(uint8_t *packet, const char *topic, 
                                      const char *data, uint8_t qos) {
   uint8_t *p = packet;
@@ -499,6 +500,9 @@ uint8_t Adafruit_MQTT::publishPacket(uint8_t *packet, const char *topic,
   // fill in packet[1] last
   p+=2;
 
+  // topic comes before packet identifier
+  p = stringprint_P(p, topic);
+
   // add packet identifier. used for checking PUBACK in QOS > 0
   if(qos > 0) {
     p[0] = (packet_id_counter >> 8) & 0xFF;
@@ -509,8 +513,6 @@ uint8_t Adafruit_MQTT::publishPacket(uint8_t *packet, const char *topic,
     packet_id_counter++;
   }
 
-  p = stringprint_P(p, topic);
-
   memcpy(p, data, strlen(data));
   p+=strlen(data);
   len = p - packet;