documentation

src/MqttPlugin.cpp

@@ -22,16 +22,11 @@ void MqttPlugin::enableConnectTask(Scheduler *scheduler)
 
 void MqttPlugin::enableProcessTask(Scheduler *scheduler)
 {
-    processTask.set(TASK_MILLISECOND * 5, TASK_FOREVER, bind(&MqttPlugin::process, this));
+    processTask.set(TASK_MILLISECOND * 5, TASK_FOREVER, bind(&PubSubClient::loop, client));
     scheduler->addTask(processTask);
     processTask.enable();
 }
 
-void MqttPlugin::process()
-{
-    client->loop();
-}
-
 void MqttPlugin::connect()
 {
     if (!client->connected())
@@ -42,8 +37,11 @@ void MqttPlugin::connect()
             // bind handlers to all local subscriptions
             for (auto const &localSub : mediator->subscriptions)
             {
-                // bind all local topics to the MQTT upstream
-                subscribe(localSub.first.c_str(), bind(&MqttPlugin::upstreamHandler, this, localSub.first.c_str(), _1));
+                // bind all local topics to the MQTT upstream once
+                if (!locallySubscribed)
+                {
+                    subscribe(localSub.first.c_str(), bind(&MqttPlugin::upstreamHandler, this, localSub.first.c_str(), _1));
+                }
                 // subscribe topic on remote queue to dispatch messages to local subscriptions
                 client->subscribe(
                     (String(mqttConfig.inTopicRoot) + String(localSub.first.c_str()))
@@ -54,11 +52,6 @@ void MqttPlugin::connect()
     }
 }
 
-void MqttPlugin::mqttPublish(String msg)
-{
-    client->publish(mqttConfig.outTopicRoot, msg.c_str());
-}
-
 void MqttPlugin::upstreamHandler(String topic, String msg)
 {
     // publish message on remote queue

src/MqttPlugin.h

@@ -25,28 +25,43 @@ class MqttPlugin : public Plugin
 {
   public:
     PubSubClient *client;
-    WiFiClient wifiClient;
-    Task connectTask;
-    Task processTask;
     MqttConfig mqttConfig;
-    vector<String> topics;
 
     MqttPlugin(MqttConfig cfg);
+
+    /**
+     * Connects to queue and triggers connect and process task.
+     * Binds downstream handler to MQTT client.
+     */
     void activate(Scheduler *scheduler);
 
   private:
-    void enableConnectTask(Scheduler *scheduler);
+    WiFiClient wifiClient;
+    Task connectTask;
+    Task processTask;
+    bool locallySubscribed = false;
 
+    void enableConnectTask(Scheduler *scheduler);
     void enableProcessTask(Scheduler *scheduler);
 
-    void process();
-
+    /**
+     * Connects to MQTT server and subscribes all topics available in the mediator 
+     * to the corresponding topic on the remote queue by prefixing the topic with inRootTopic.
+     * Creates shadow subscriptions of every local topic to propagate messages to the remote queue via upstreamHandler.
+     */
     void connect();
 
-    void mqttPublish(String msg);
-
+    /**
+     * The upstream handler is bound to every local subscription.
+     * It passes the message to the remote queue by prefixing the outRootTopic.
+     */ 
     void upstreamHandler(String topic, String msg);
 
+    /**
+     * The downstream handler is bound to the remote counterpart of local subscriptions,
+     * prefixed with inRootTopic.
+     * Everything after the prefix is used as local topic and dispatched to local subscriptions.
+     */ 
     void downstreamHandler(char *topic, uint8_t *payload, unsigned int length);
 };
 

src/examples/basic/main.cpp

@@ -17,7 +17,7 @@ void setup()
     sprocket = new Sprocket(
         {STARTUP_DELAY, SERIAL_BAUD_RATE});
     sprocket->subscribe("local/topic", [](String msg){
-        Serial.println("Local: " + msg);
+        PRINT_MSG(Serial, "LOCAL", msg.c_str());
     });
     sprocket->addTask(publishHeap);
     sprocket->addPlugin(