Example when wifi is not connected

src/TinyMqtt.cpp

@@ -93,11 +93,29 @@ void MqttBroker::loop()
 	}
 }
 
-void MqttBroker::publish(const Topic& topic, MqttMessage& msg)
+// Should be called for inside and outside incoming publishes (all)
+void MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessage& msg)
 {
-	Serial << "  publish" << __LINE__ << endl;
 	for(auto client: clients)
-		client->publish(topic, msg);
+	{
+		bool doit = false;
+		if (broker && broker->connected())	// Connected: R2 R3 R5 R6
+		{
+			if (!client->isLocal())	// R2 go outside allowed
+				doit = true;
+			else // R3 any client to outside allowed
+				doit = true;
+		}
+		else // Disconnected: R3 R4 R5
+		{
+			if (!source->isLocal()) // R3
+			  doit = true;
+			else if (client->isLocal())	// R4 local -> local
+				doit = true;
+		}
+
+		if (doit) client->publish(topic, msg);	// goes outside R2
+	}
 }
 
 bool MqttBroker::compareString(
@@ -234,7 +252,7 @@ void MqttClient::processMessage()
 				if (qos) payload+=2;	// ignore packet identifier if any
 				// TODO reset DUP
 				// TODO reset RETAIN
-				parent->publish(published, message);
+				parent->publish(this, published, message);
 				// TODO should send PUBACK
 				bclose = false;
 			}
@@ -270,15 +288,14 @@ bool Topic::matches(const Topic& topic) const
 	return false;
 }
 
-// publish from local client to a broker
+// publish from local client
 void MqttClient::publish(const Topic& topic, const char* payload, size_t pay_length)
 {
-	Serial << "  publish" << __LINE__ << endl;
 	message.create(MqttMessage::Publish);
 	message.add(topic);
 	message.add(payload, pay_length);
 	if (parent)
-		parent->publish(topic, message);
+		parent->publish(this, topic, message);
 	else if (client)
 		publish(topic, message);
 	else
@@ -288,16 +305,12 @@ void MqttClient::publish(const Topic& topic, const char* payload, size_t pay_len
 // republish a received publish if it matches any in subscriptions
 void MqttClient::publish(const Topic& topic, MqttMessage& msg)
 {
-	Serial << "  publish " << topic.c_str() << __LINE__ << endl;
 	for(const auto& subscription: subscriptions)
 	{
-		Serial << "    check " << subscription.c_str() << __LINE__ << endl;
 		if (subscription.matches(topic))
 		{
-			Serial << "    matche !" << endl;
 			if (client)
 			{
-				// Serial << "Republishing " << topic.str().c_str() << " to " << clientId.c_str() << endl;
 				msg.sendTo(this);
 			}
 			else if (callback)

src/TinyMqtt.h

@@ -125,6 +125,8 @@ class MqttClient
 		void subscribe(Topic topic) { subscriptions.insert(topic); }
 		void unsubscribe(Topic& topic);
 
+		bool isLocal() const { return client==nullptr; }
+
 	private:
 		friend class MqttBroker;
 		MqttClient(MqttBroker* parent, WiFiClient& client);
@@ -146,8 +148,33 @@ class MqttClient
 		CallBack callback;
 };
 
+/***********************************************
+ * R1 - accept external cnx
+ * R2 - allows all clients pusblish to go outside
+ * R3 - allows ext publish to all clients
+ * R4 - allows local publish to local clients
+ * R5 - tries to connect elsewhere (*)
+ * R6 - disconnect external clients
+ * ---------------------------------------------
+ *  (*) single client or ip range
+ * ---------------------------------------------
+ *
+ * =============================================+
+ *              | connected     | not connected |
+ * -------------+---------------+---------------+
+ * proxy broker | R2 R3 R5 R6   | R3 R4 R5      |
+ * normal broker| R2 R3 R5 R6   | R1 R3 R4 R5   |
+ * -------------+---------------+---------------+
+ *
+ */
 class MqttBroker
 {
+	enum State
+	{
+		Disconnected,	// Also the initial state
+		Connecting,		// connect and sends a fake publish to avoid circular cnx
+		Connected,		// this->broker is connected and circular cnx avoided
+	};
 	public:
 		MqttBroker(uint16_t port);
 
@@ -156,6 +183,9 @@ class MqttBroker
 
 		uint8_t port() const { return server.port(); }
 
+		void connect(std::string host, uint32_t port=1883);
+		bool connected() const { return state == Connected; }
+
 	private:
 		friend class MqttClient;
 
@@ -166,7 +196,7 @@ class MqttBroker
 		{ return compareString(auth_password, password, len); }
 
 
-		void publish(const Topic& topic, MqttMessage& msg);
+		void publish(const MqttClient* source, const Topic& topic, MqttMessage& msg);
 
 		// For clients that are added not by the broker itself
 		void addClient(MqttClient* client);
@@ -178,4 +208,7 @@ class MqttBroker
 
 		const char* auth_user = "guest";
 		const char* auth_password = "guest";
+		State state = Disconnected;
+
+		MqttClient* broker = nullptr;
 };