MqttClient was unable to publish in some cases

src/TinyMqtt.cpp

@@ -141,8 +141,10 @@ void MqttBroker::loop()
 	}
 }
 
-void MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessage& msg)
+MqttError MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessage& msg)
 {
+	MqttError retval = MqttOk;
+
 	debug("publish ");
 	int i=0;
 	for(auto client: clients)
@@ -158,7 +160,7 @@ void MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessa
 			if (source == broker)	// broker -> clients
 				doit = true;
 			else									// clients -> broker
-				broker->publish(topic, msg);
+				retval=broker->publish(topic, msg);
 		}
 		else // Disconnected: R7
 		{
@@ -170,6 +172,7 @@ void MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessa
 		if (doit) client->publish(topic, msg);
 		debug("");
 	}
+	return retval;
 }
 
 bool MqttBroker::compareString(
@@ -390,22 +393,25 @@ bool Topic::matches(const Topic& topic) const
 }
 
 // publish from local client
-void MqttClient::publish(const Topic& topic, const char* payload, size_t pay_length)
+MqttError MqttClient::publish(const Topic& topic, const char* payload, size_t pay_length)
 {
-	message.create(MqttMessage::Publish);
-	message.add(topic);
-	message.add(payload, pay_length);
+	MqttMessage msg;
+	msg.create(MqttMessage::Publish);
+	msg.add(topic);
+	msg.add(payload, pay_length);
 	if (parent)
-		parent->publish(this, topic, message);
+		return parent->publish(this, topic, msg);
 	else if (client)
-		publish(topic, message);
+		msg.sendTo(this);
 	else
-		Serial << "  Should not happen" << endl;
+		return MqttNowhereToSend;
 }
 
 // republish a received publish if it matches any in subscriptions
-void MqttClient::publish(const Topic& topic, MqttMessage& msg)
+MqttError MqttClient::publish(const Topic& topic, MqttMessage& msg)
 {
+	MqttError retval=MqttOk;
+
 	debug("mqttclient publish " << subscriptions.size());
 	for(const auto& subscription: subscriptions)
 	{
@@ -419,11 +425,12 @@ void MqttClient::publish(const Topic& topic, MqttMessage& msg)
 			}
 			else if (callback)
 			{
-				callback(this, topic, nullptr, 0);	// TODO 
+				callback(this, topic, nullptr, 0);	// TODO Payload
 			}
 		}
 		Serial << endl;
 	}
+	return retval;
 }
 
 void MqttMessage::reset()

src/TinyMqtt.h

@@ -4,6 +4,11 @@
 #include <string>
 #include "StringIndexer.h"
 
+enum MqttError
+{
+	MqttOk = 0,
+	MqttNowhereToSend=1,
+};
 
 class Topic : public IndexedString
 {
@@ -121,9 +126,9 @@ class MqttClient
 		void setCallback(CallBack fun) {callback=fun; };
 
 		// Publish from client to the world
-		void publish(const Topic&, const char* payload, size_t pay_length);
-		void publish(const Topic& t, const std::string& s) { publish(t,s.c_str(),s.length());}
-		void publish(const Topic& t) { publish(t, nullptr, 0);};
+		MqttError publish(const Topic&, const char* payload, size_t pay_length);
+		MqttError publish(const Topic& t, const std::string& s) { return publish(t,s.c_str(),s.length());}
+		MqttError publish(const Topic& t) { return publish(t, nullptr, 0);};
 
 		void subscribe(Topic topic) { subscriptions.insert(topic); }
 		void unsubscribe(Topic& topic);
@@ -151,7 +156,7 @@ class MqttClient
 		friend class MqttBroker;
 		MqttClient(MqttBroker* parent, WiFiClient& client);
 		// republish a received publish if topic matches any in subscriptions
-		void publish(const Topic& topic, MqttMessage& msg);
+		MqttError publish(const Topic& topic, MqttMessage& msg);
 
 		void clientAlive(uint32_t more_seconds);
 		void processMessage();
@@ -214,7 +219,7 @@ class MqttBroker
 		{ return compareString(auth_password, password, len); }
 
 
-		void publish(const MqttClient* source, const Topic& topic, MqttMessage& msg);
+		MqttError publish(const MqttClient* source, const Topic& topic, MqttMessage& msg);
 
 		// For clients that are added not by the broker itself
 		void addClient(MqttClient* client);