[issue #84] Fix and unit test added

src/TinyMqtt.cpp

@@ -646,6 +646,7 @@ void MqttClient::processMessage(MqttMessage* mesg)
       if (mqtt_connected() or tcp_client == nullptr)
       {
         uint8_t qos = mesg->flags();
+        qos = (qos / 2) & 3;
         payload = header;
         mesg->getString(payload, len);
         Topic published(payload, len);
@@ -654,8 +655,19 @@ void MqttClient::processMessage(MqttMessage* mesg)
           Console << "Received Publish (" << published.str().c_str() << ") size=" << (int)len << endl;
         #endif
         // << '(' << string(payload, len).c_str() << ')'  << " msglen=" << mesg->length() << endl;
-        if (qos) payload+=2;  // ignore packet identifier if any
+        const char* ID;     // remove PublishID() to avoid misuse
+        if (qos) {
+          ID = payload;
+          payload+=2;  // ignore packet identifier if any
+        }
         len=mesg->end()-payload;
+        if (qos == 1)
+        {
+          MqttMessage msg(MqttMessage::Type::PubAck);
+          msg.add(ID[0]);  // MessageID high
+          msg.add(ID[1]);  // MessageID low
+          msg.sendTo(this);
+        }
         // TODO reset DUP
         // TODO reset RETAIN
 

tests/network-tests/network-tests.ino

@@ -349,6 +349,39 @@ test(retained_message)
   assertEqual(published.size(), (size_t)2);
 }
 
+test(retained_payload)  // # issue #84
+{
+  published.clear();
+
+  start_many_wifi_esp(2, true);
+  assertEqual(WiFi.status(), WL_CONNECTED);
+
+  MqttBroker broker(1883);
+  broker.begin();
+  broker.retain(10);
+  IPAddress broker_ip = WiFi.localIP();
+
+  MqttClient local_client(&broker, "sender");
+
+  // Send a retained message
+  // No remote client connected
+  local_client.publish("topic", "retained", true);
+  for(int i=0; i<2; i++) { broker.loop(); local_client.loop(); };
+
+  // No connect a client from 2nd Esp
+  ESP8266WiFiClass::selectInstance(2);
+  MqttClient remote_client("receiver");
+  remote_client.connect(broker_ip, 1883);
+  remote_client.setCallback(onPublish);
+  remote_client.subscribe("#");
+
+  assertTrue(remote_client.connected());
+  for(int i=0; i<10; i++) { broker.loop(); local_client.loop(); remote_client.loop(); };
+
+  // Check that the retained message is published
+  assertEqual(lastPayload, "retained");
+}
+
 test(remote_client_disconnect_reconnect)
 {
   published.clear();