Release 0.4.0

Fix too long time

README.md

@@ -25,6 +25,10 @@ ESP 8266 is a small and very capable Mqtt Broker and Client
 no need for having tons of clients (also RAM is the problem with many clients)
 * Test what is the real max number of clients for broker. As far as I saw, 3k is needed per client which would make more than 10 clients critical.
 * MqttMessage uses a buffer 256 bytes which is usually far than needed.
+* MqttClient auto reconnection
+* MqttClient auto re-subscribe
+* MqttClient does not callback payload...
+* MqttClient user/password
 
 ## Quickstart
 

examples/client-with-wifi/client-with-wifi.ino

@@ -1,10 +1,8 @@
 #include <TinyMqtt.h>   // https://github.com/hsaturn/TinyMqtt
 #include <Streaming.h>  // https://github.com/janelia-arduino/Streaming
 
-// TODO should be renamed to most-complete setup
-
 /** 
-  * Local broker that accept connections
+  * Local broker that accept connections and two local clients
   *
   * pros - Reduces internal latency (when publish is received by the same ESP)
   *      - Reduces wifi traffic
@@ -31,11 +29,11 @@ MqttBroker broker(1883);
 MqttClient mqtt_a(&broker);
 MqttClient mqtt_b(&broker);
 
-void onPublishA(const Topic& topic, const char* payload, size_t length)
-{ Serial << "--> A Received " << topic.c_str() << endl; }
+void onPublishA(const MqttClient* source, const Topic& topic, const char* payload, size_t length)
+{ Serial << endl << "---------> A Received " << topic.c_str() << endl; }
 
-void onPublishB(const Topic& topic, const char* payload, size_t length)
-{ Serial << "--> B Received " << topic.c_str() << endl; }
+void onPublishB(const MqttClient* source, const Topic& topic, const char* payload, size_t length)
+{ Serial << endl << "---------> B Received " << topic.c_str() << endl; }
 
 void setup()
 {
@@ -67,7 +65,7 @@ void loop()
   mqtt_b.loop();
 
   // ============= client A publish ================
-	static const int intervalA = 50000;
+	static const int intervalA = 5000;  // publishes every 5s
 	static uint32_t timerA = millis() + intervalA;
 	
 	if (millis() > timerA)
@@ -78,7 +76,7 @@ void loop()
 	}
 
   // ============= client B publish ================
-	static const int intervalB = 30000;	// will send topic each 5000 ms
+	static const int intervalB = 7000;	// will send topic each 7s
 	static uint32_t timerB = millis() + intervalB;
 	
 	if (millis() > timerB)

examples/simple-client/simple-client.ino

@@ -16,6 +16,9 @@
 
 #include <my_credentials.h>
 
+static float temp=19;
+static MqttClient client;
+
 void setup() 
 {
   Serial.begin(115200);
@@ -29,8 +32,18 @@ void setup()
 	{ delay(500); Serial << '.'; }
 
   Serial << "Connected to " << ssid << "IP address: " << WiFi.localIP() << endl;  
+
+	client.connect("192.168.1.40", 1883);	// Put here your broker ip / port
+
 }
 
 void loop()
 {
+	client.loop();
+
+	delay(1000);
+
+	temp += (random(100)>50 ? 0.1 : -0.1);
+	client.publish("sensor/temperature", String(temp));
+
 }

examples/tinymqtt-test/tinymqtt-test.ino

@@ -1,9 +1,10 @@
+#define TINY_MQTT_DEBUG
 #include <TinyMqtt.h>   // https://github.com/hsaturn/TinyMqtt
 #include <Streaming.h>  // https://github.com/janelia-arduino/Streaming
 #include <map>
 
 /** 
-  * Local broker that accept connections
+  * Console allowing to make any kind of test.
   *
   * pros - Reduces internal latency (when publish is received by the same ESP)
   *      - Reduces wifi traffic
@@ -25,11 +26,13 @@
 
 std::string topic="sensor/temperature";
 
-MqttBroker broker(1883);
-
 void onPublish(const MqttClient* srce, const Topic& topic, const char* payload, size_t length)
 { Serial << "--> " << srce->id().c_str() << ": ======> received " << topic.c_str() << endl; }
 
+std::map<std::string, MqttClient*> clients;
+std::map<std::string, MqttBroker*> brokers;
+
+
 void setup()
 {
   Serial.begin(115200);
@@ -46,17 +49,31 @@ void setup()
 
   Serial << "Connected to " << ssid << "IP address: " << WiFi.localIP() << endl;
 
-	broker.begin();
+	MqttBroker* broker = new MqttBroker(1883);
+	broker->begin();
+	brokers["broker"] = broker;
 }
 
-std::string getword(std::string& str, const char* if_empty=nullptr)
+int getint(std::string& str, const int if_empty=0, char sep=' ')
 {
 	std::string sword;
-	while(str.length() && str[0]!=' ')
+	while(str.length() && str[0]!=sep)
 	{
 		sword += str[0]; str.erase(0,1);
 	}
-	while(str[0]==' ') str.erase(0,1);
+	while(str[0]==sep) str.erase(0,1);
+	if (if_empty and sword.length()==0) sword=if_empty;
+	return atoi(sword.c_str());
+}
+
+std::string getword(std::string& str, const char* if_empty=nullptr, char sep=' ')
+{
+	std::string sword;
+	while(str.length() && str[0]!=sep)
+	{
+		sword += str[0]; str.erase(0,1);
+	}
+	while(str[0]==sep) str.erase(0,1);
 	if (if_empty and sword.length()==0) return if_empty;
 	return sword;
 }
@@ -128,7 +145,7 @@ class automatic
 						autop->bon=false;
 					else if (s=="interval")
 					{
-						int32_t i=atol(getword(cmd).c_str());
+						int32_t i=getint(cmd);
 						if (i)
 							autop->interval(atol(s.c_str()));
 						else
@@ -181,35 +198,12 @@ bool compare(std::string s, const char* cmd)
 	return strncmp(cmd, s.c_str(), s.length())==0;
 }
 
-std::map<std::string, MqttClient*> clients;
-
 using ClientFunction = void(*)(std::string& cmd, MqttClient* publish);
 
-void clientCommand(std::string& cmd, ClientFunction func, bool canBeNull=false)
-{
-	std::string s=getword(cmd);
-	bool found = clients.find(s) != clients.end();
-
-	if (canBeNull && found==false)
-	{
-		cmd += ' ' + s;
-	}
-
-	if (found or canBeNull)
-	{
-		MqttClient* publish = publish = clients[s];
-		func(cmd, publish);
-	}
-	else
-	{
-		Serial << "client not found (" << s.c_str() << ")" << endl;
-		cmd="";
-	}
-}
-
 void loop()
 {
-	broker.loop();
+	for(auto it: brokers)
+		it.second->loop();
 
 	for(auto it: clients)
 		it.second->loop();
@@ -223,90 +217,209 @@ void loop()
 
 		if (c==10 or c==14)
 		{
-			Serial << "------------------------------------------------------" << endl;
+			Serial << "----------------[ " << cmd.c_str() << " ]--------------" << endl;
+			static std::string last_cmd;
+			if (cmd=="!")
+				cmd=last_cmd;
+			else
+				last_cmd=cmd;
 			while(cmd.length())
 			{
-				std::string s = getword(cmd);
+				std::string s;
+				MqttBroker* broker = nullptr;
+				MqttClient* client = nullptr;
+
+				// client.function notation
+				// ("a.fun " becomes "fun a ")
+				if (cmd.find('.') != std::string::npos)
+				{
+					s=getword(cmd, nullptr, '.');
+
+					if (clients.find(s) != clients.end())
+					{
+						client = clients[s];
+					}
+					else if (brokers.find(s) != brokers.end())
+					{
+						broker = brokers[s];
+					}
+					else
+					{
+						Serial << "Unknown class (" << s.c_str() << ")" << endl;
+						cmd="";
+					}
+				}
+				
+				s = getword(cmd);
+				if (compare(s, "delete"))
+				{
+					if (client==nullptr && broker==nullptr)
+					{
+						s = getword(cmd);
+						if (clients.find(s) != clients.end())
+						{
+							client = clients[s];
+						}
+						else if (brokers.find(s) != brokers.end())
+						{
+							broker = brokers[s];
+						}
+						else
+							Serial << "Unable to find (" << s.c_str() << ")" << endl;
+					}
+					if (client)
+					{
+						clients.erase(s);
+						for (auto it: clients)
+						{
+							if (it.second != client) continue;
+							Serial << "deleted" << endl;
+							clients.erase(it.first);
+							break;
+						}
+						cmd += " ls";
+					}
+					else if (broker)
+					{
+						for(auto it: brokers)
+						{
+							Serial << (int32_t)it.second << '/' << (int32_t)broker << endl;
+							if (broker != it.second) continue;
+							Serial << "deleted" << endl;
+							brokers.erase(it.first);
+							break;
+						}
+						cmd += " ls";
+					}
+					else
+						Serial << "Nothing to delete" << endl;
+				}
+				else if (broker)
+				{
 					if (compare(s,"connect"))
 				  {
-					clientCommand(cmd, [](std::string& cmd, MqttClient* publish)
-							{ publish->connect(getword(cmd,"192.168.1.40").c_str(), 1883); });
-				}
-				else if (compare(s,"publish"))
-				{
-					clientCommand(cmd, [](std::string& cmd, MqttClient* publish)
-							{ publish->publish(getword(cmd, topic.c_str())); });
-				}
-				else if (compare(s,"subscribe"))
-				{
-					clientCommand(cmd, [](std::string& cmd, MqttClient* publish)
-							{ publish->subscribe(getword(cmd, topic.c_str())); });
+						Serial << "NYI" << endl;
 				  }
 					else if (compare(s, "view"))
 					{
-					clientCommand(cmd, [](std::string& cmd, MqttClient* publish)
-							{ publish->dump(); });
+						broker->dump();
+					}
+			  }
+				else if (client)
+				{
+					if (compare(s,"connect"))
+					{
+						client->connect(getword(cmd,"192.168.1.40").c_str(), 1883);
+						Serial << (client->connected() ? "connected." : "not connected") << endl;
+					}
+					else if (compare(s,"publish"))
+					{
+						auto ok=client->publish(getword(cmd, topic.c_str()));
+						if (ok != MqttOk)
+						{
+							Serial << "## ERROR " << ok << endl;
+						}
+					}
+					else if (compare(s,"subscribe"))
+					{
+						client->subscribe(getword(cmd, topic.c_str()));
+					}
+					else if (compare(s, "view"))
+					{
+						client->dump();
+					}
 				}
 				else if (compare(s, "auto"))
 				{
-					clientCommand(cmd, [](std::string& cmd, MqttClient* publish)
-							{ automatic::command(publish, cmd);
-							if (publish == nullptr)
+					automatic::command(client, cmd);
+					if (client == nullptr)
 						cmd.clear();
-							}, true);
 				}
-				else if (compare(s, "new"))
+				else if (compare(s, "broker"))
 				{
 					std::string id=getword(cmd);
-					if (id.length())
+					if (id.length() or brokers.find(id)!=brokers.end())
 					{
-						MqttClient* client = new MqttClient(&broker);
+						int port=getint(cmd, 0);
+						if (port)
+						{
+							MqttBroker* broker = new MqttBroker(port);
+							broker->begin();
+
+							brokers[id] = broker;
+							Serial << "new broker (" << id.c_str() << ")" << endl;
+						}
+						else
+							Serial << "Missing port" << endl;
+					}
+					else
+						Serial << "Missing or existing broker name (" << id.c_str() << ")" << endl;
+					cmd+=" ls";
+				}
+				else if (compare(s, "client"))
+				{
+					std::string id=getword(cmd);
+					if (id.length() or clients.find(id)!=clients.end())
+					{
+						s=getword(cmd);	// broker name
+						if (s=="" or brokers.find(s) != brokers.end())
+						{
+							MqttBroker* broker = nullptr;
+							if (s.length()) broker = brokers[s];
+							MqttClient* client = new MqttClient(broker);
 							client->id(id);
 							clients[id]=client;
 							client->setCallback(onPublish);
 							client->subscribe(topic);
+							Serial << "new client (" << id.c_str() << ", " << s.c_str() << ')' << endl;
+						}
+						else if (s.length())
+						{
+							Serial << " not found." << endl;
+						}
 					}
 					else
-						Serial << "missing id" << endl;
+						Serial << "Missing or existing client name" << endl;
 					cmd+=" ls";
 				}
-				else if (compare(s, "delete"))
+				else if (compare(s, "ls") or compare(s, "view"))
 				{
-					s = getword(cmd);
-					auto it=clients.find(s);
-					if (it != clients.end())
-					{
-						delete it->second;
-						clients.erase(it);
-						cmd+=" ls";
-					}
-					else
-						Serial << "Unknown client (" << s.c_str() << ")" << endl;
-				}
-				else if (compare(s, "ls"))
-				{
-					Serial << "main  : " << clients.size() << " client/s." << endl;
+					Serial << "--< " << clients.size() << " client/s. >--" << endl;
 					for(auto it: clients)
 					{
 						Serial << "  "; it.second->dump();
 					}
-					broker.dump();
+
+					Serial << "--< " << brokers.size() << " brokers/s. >--" << endl;
+					for(auto it: brokers)
+					{
+						Serial << " ==[ Broker: " << it.first.c_str() << " ]== ";
+						it.second->dump();
+					}
 				}
 				else if (compare(s, "reset"))
 					ESP.restart();
+				else if (compare(s, "ip"))
+					Serial << "IP: " << WiFi.localIP() << endl;
 				else if (compare(s,"help"))
 				{
 					Serial << "syntax:" << endl;
-					Serial << "    new/delete $id" << endl;
-					Serial << "    connect $id [ip]" << endl;
-					Serial << "    subscribe $id [topic]" << endl;
-					Serial << "    publish $id [topic]" << endl;
-					Serial << "    view $id " << endl;
+					Serial << "  MqttBroker:" << endl;
+					Serial << "    broker {name} {port} : create a new broker" << endl;
+					Serial << endl;
+					Serial << "  MqttClient:" << endl;
+					Serial << "    client {name} {parent broker} : create a client then" << endl;
+					Serial << "      name.connect  [ip]" << endl;
+					Serial << "      name.subscribe [topic]" << endl;
+					Serial << "      name.publish [topic]" << endl;
+					Serial << "      name.view" << endl;
+					Serial << "      name.delete" << endl;
+
 					automatic::help();
 					Serial << endl;
 					Serial << "    help" << endl;
-					Serial << "    ls" << endl;
-					Serial << "    reset" << endl;
+					Serial << "    ls / ip / reset" << endl;
+					Serial << "    !  repeat last command" << endl;
 					Serial << endl;
 					Serial << "  $id : name of the client." << endl;
 					Serial << "  default topic is '" << topic.c_str() << "'" << endl;
@@ -314,6 +427,8 @@ void loop()
 				}
 				else
 				{
+					while(s[0]==' ') s.erase(0,1);
+					if (s.length())
 						Serial << "Unknown command (" << s.c_str() << ")" << endl;
 				}
 			}

library.json

@@ -6,7 +6,7 @@
         "type": "git",
         "url": "https://github.com/hsaturn/TinyMqtt.git"
     },
-    "version": "0.2",
+    "version": "0.4.0",
     "exclude": "",
     "examples": "examples/*/*.ino",
     "frameworks": "arduino",

library.properties

@@ -1,9 +1,9 @@
 name=TinyMqtt
-version=0.2.0
-author=HSaturn <hsaturn@gmail.com>
-maintainer=HSaturn <hsaturn@gmail.com>
+version=0.4.0
+author=Francois BIOT, HSaturn, <hsaturn@gmail.com>
+maintainer=Francois BIOT, HSaturn, <hsaturn@gmail.com>
 sentence=A tiny broker and client library for MQTT messaging.
-paragraph=MQTT is a lightweight messaging protocol ideal for small devices. This library allows you to send and receive MQTT messages. It does support MQTT 3.1.1 without any QOS.
+paragraph=MQTT is a lightweight messaging protocol ideal for small devices. This library allows you to send and receive MQTT messages and to jhost a broker in your ESP. It does support MQTT 3.1.1 without any QOS.
 category=Communication
 url=https://github.com/hsaturn/TinyMqtt
 architectures=*

src/StringIndexer.h

@@ -2,7 +2,7 @@
 #include <map>
 #include <string>
 #include <string.h>
-#include <Streaming.h>
+// #include <Streaming.h>
 #include <ESP8266WiFi.h>
 
 /***
@@ -36,7 +36,7 @@ class StringIndexer
 				{
 					strings[index].str = std::string(str, len);
 					strings[index].used++;
-					Serial << "Creating index " << index << " for (" << strings[index].str.c_str() << ") len=" << len << endl;
+					// Serial << "Creating index " << index << " for (" << strings[index].str.c_str() << ") len=" << len << endl;
 					return index;
 				}
 			}
@@ -66,7 +66,7 @@ class StringIndexer
 				if (it->second.used == 0)
 				{
 					strings.erase(it);
-					Serial << "Removing string(" << it->second.str.c_str() << ") size=" << strings.size() << endl;
+					// Serial << "Removing string(" << it->second.str.c_str() << ") size=" << strings.size() << endl;
 				}
 			}
 		}

src/TinyMqtt.cpp

@@ -2,12 +2,6 @@
 #include <sstream>
 #include <Streaming.h>
 
-#if 1
-#define debug(what) { Serial << __LINE__ << ' ' << what << endl; delay(100); }
-#else
-#define debug(what) {}
-#endif
-
 void outstring(const char* prefix, const char*p, uint16_t len)
 {
 	return;
@@ -20,10 +14,19 @@ MqttBroker::MqttBroker(uint16_t port) : server(port)
 {
 }
 
+MqttBroker::~MqttBroker()
+{
+	while(clients.size())
+	{
+		delete clients[0];
+	}
+}
+
+// private constructor used by broker only
 MqttClient::MqttClient(MqttBroker* parent, WiFiClient& new_client)
 	: parent(parent)
 {
-	client = new_client ? new WiFiClient(new_client) : nullptr;
+	client = new WiFiClient(new_client);
 	alive = millis()+5000;	// client expires after 5s if no CONNECT msg
 }
 
@@ -32,7 +35,7 @@ MqttClient::MqttClient(MqttBroker* parent)
 {
 		client = nullptr;
 
-		parent->addClient(this);
+		if (parent) parent->addClient(this);
 }
 
 MqttClient::~MqttClient()
@@ -61,9 +64,9 @@ void MqttClient::connect(std::string broker, uint16_t port)
 {
 	debug("cnx: closing");
 	close();
-	debug("cnx: closed");
 	if (client) delete client;
 	client = new WiFiClient;
+	debug("Trying to connect to " << broker.c_str() << ':' << port);
 	if (client->connect(broker.c_str(), port))
 	{
 	  debug("cnx: connecting");
@@ -72,7 +75,7 @@ void MqttClient::connect(std::string broker, uint16_t port)
 		message.add(0x4);	// Mqtt protocol version 3.1.1
 		message.add(0x0);	// Connect flags         TODO user / name
 
-		keep_alive = 1;
+		keep_alive = 1;			// TODO not configurable
 		message.add(0x00); // keep_alive
 		message.add((char)keep_alive);
 		message.add(clientId);
@@ -119,7 +122,7 @@ void MqttBroker::loop()
 	for(int i=0; i<clients.size(); i++)
 	{
 		auto client = clients[i];
-    if(client->connected())
+    if (client->connected())
     {
 			client->loop();
 		}
@@ -133,8 +136,10 @@ 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)
@@ -150,7 +155,7 @@ 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
 		{
@@ -162,6 +167,7 @@ void MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessa
 		if (doit) client->publish(topic, msg);
 		debug("");
 	}
+	return retval;
 }
 
 bool MqttBroker::compareString(
@@ -174,10 +180,10 @@ bool MqttBroker::compareString(
 	return *good==0;
 }
 
-void MqttMessage::getString(char* &buffer, uint16_t& len)
+void MqttMessage::getString(const char* &buff, uint16_t& len)
 {
-	len = (buffer[0]<<8)|(buffer[1]);
-	buffer+=2;
+	len = (buff[0]<<8)|(buff[1]);
+	buff+=2;
 }
 
 void MqttClient::clientAlive(uint32_t more_seconds)
@@ -198,8 +204,9 @@ void MqttClient::loop()
 		{
 			debug("timeout client");
 			close();
+			debug("closed");
 		}
-		else
+		else if (client && client->connected())
 		{
 			uint16_t pingreq = MqttMessage::Type::PingReq;
 			client->write((uint8_t*)(&pingreq), 2);
@@ -226,7 +233,7 @@ void MqttClient::processMessage()
 	std::string s;
 	// Serial << "---> INCOMING " << _HEX(message.type()) << ", mem=" << ESP.getFreeHeap() << endl;
   auto header = message.getVHeader();
-  char* payload;
+  const char* payload;
   uint16_t len;
 	bool bclose=true;
 
@@ -382,22 +389,25 @@ 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, false);
 	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)
 	{
@@ -411,24 +421,24 @@ 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()
 {
-	curr=buffer;
-	*curr=0;	// Type Unknown
+	buffer.clear();
 	state=FixedHeader;
 	size=0;
 }
 
 void MqttMessage::incoming(char in_byte)
 {
-	*curr++ = in_byte;
+	buffer += in_byte;
 	switch(state)
 	{
 		case FixedHeader:
@@ -443,7 +453,7 @@ void MqttMessage::incoming(char in_byte)
 			}
 			else if ((in_byte & 0x80) == 0)
 			{
-				vheader = curr;
+				vheader = buffer.length();
 				if (size==0)
 					state = Complete;
 				else
@@ -464,22 +474,24 @@ void MqttMessage::incoming(char in_byte)
 			break;
 		case Complete:
 		default:
-			curr--;
 			Serial << "Spurious " << _HEX(in_byte) << endl;
-			state = Error;
+			reset();
 			break;
 	}
-	if (curr-buffer > 250)
+	if (buffer.length() > MaxBufferLength)	// TODO magic 256 ?
 	{
-		debug("Spurious byte " << _HEX(in_byte));
-		curr=buffer;
+		debug("Too long " << state);
+		reset();
 	}
 }
 
-void MqttMessage::add(const char* p, size_t len)
+void MqttMessage::add(const char* p, size_t len, bool addLength)
 {
+	if (addLength)
+	{
 		incoming(len>>8);
 		incoming(len & 0xFF);
+	}
 	while(len--) incoming(*p++);
 }
 
@@ -496,29 +508,26 @@ void MqttMessage::encodeLength(char* msb, int length)
 
 void MqttMessage::sendTo(MqttClient* client)
 {
-	if (curr-buffer-2 >= 0)
+	if (buffer.size()>2)
 	{
-		encodeLength(buffer+1, curr-buffer-2);
+		encodeLength(&buffer[1], buffer.size()-2);
 		// hexdump("snd");
-		client->write(buffer, curr-buffer);
+		client->write(&buffer[0], buffer.size());
 	}
 	else
 	{
 		Serial << "??? Invalid send" << endl;
-		Serial << (long)end() << "-" << (long)buffer << endl;
 	}
 }
 
 void MqttMessage::hexdump(const char* prefix) const
 {
 	if (prefix) Serial << prefix << ' ';
-	Serial << (long)buffer << "-" << (long)curr << " : ";
-		const char* p=buffer;
-		while(p!=curr)
+	Serial << "size(" << buffer.size() << ") : ";
+		for(const char chr: buffer)
 		{
-			if (*p<16) Serial << '0';
-			Serial << _HEX(*p) << ' ';
-			p++;
+			if (chr<16) Serial << '0';
+			Serial << _HEX(chr) << ' ';
 		}
 		Serial << endl;
 }

src/TinyMqtt.h

@@ -4,7 +4,18 @@
 #include <string>
 #include "StringIndexer.h"
 
-#define MaxBufferLength 255
+#ifdef TINY_MQTT_DEBUG
+  #include <Streaming.h>
+  #define debug(what) { Serial << __LINE__ << ' ' << what << endl; delay(100); }
+#else
+  #define debug(what) {}
+#endif
+
+enum MqttError
+{
+	MqttOk = 0,
+	MqttNowhereToSend=1,
+};
 
 class Topic : public IndexedString
 {
@@ -21,6 +32,7 @@ class Topic : public IndexedString
 class MqttClient;
 class MqttMessage
 {
+	const uint16_t MaxBufferLength = 255;
 	public:
 		enum Type
 		{
@@ -48,18 +60,18 @@ class MqttMessage
 		MqttMessage(Type t) { create(t); }
 		void incoming(char byte);
 		void add(char byte) { incoming(byte); }
-		void add(const char* p, size_t len);
+		void add(const char* p, size_t len, bool addLength=true );
 		void add(const std::string& s) { add(s.c_str(), s.length()); }
 		void add(const Topic& t) { add(t.str()); }
-		char* getVHeader() const { return vheader; }
-		char* end() const { return curr; }
-		uint16_t length() const { return curr-buffer; }
+		const char* end() const { return &buffer[0]+buffer.size(); }
+		const char* getVHeader() const { return &buffer[vheader]; }
+		uint16_t length() const { return buffer.size(); }
 
 		void reset();
 
 		// buff is MSB/LSB/STRING
 		// output buff+=2, len=length(str)
-		void getString(char* &buff, uint16_t& len);
+		static void getString(const char* &buff, uint16_t& len);
 
 
 		Type type() const
@@ -69,9 +81,9 @@ class MqttMessage
 
 		void create(Type type)
 		{
-			buffer[0]=type;
-			curr=buffer+2;
-			vheader=curr;
+			buffer=(char)type;
+			buffer+='\0';
+			vheader=2;
 			size=0;
 			state=Create;
 		}
@@ -81,9 +93,8 @@ class MqttMessage
 	private:
 		void encodeLength(char* msb, int length);
 
-	  char buffer[256];	// TODO why 256 ? (should be replaced by a std::string)
-		char* vheader;
-		char* curr;
+		std::string buffer;
+		uint8_t vheader;
 		uint16_t size;	// bytes left to receive
 		State state;
 };
@@ -104,13 +115,16 @@ class MqttClient
 	};
 	public:
 		MqttClient(MqttBroker*);
+		MqttClient() : MqttClient(nullptr) {};
 
 		~MqttClient();
 
 		void connect(MqttBroker* parent);
 		void connect(std::string broker, uint16_t port);
 
-		bool connected() { return client==nullptr || client->connected(); }
+		bool connected() { return
+			(parent!=nullptr and client==nullptr) or
+			(client and client->connected()); }
 		void write(const char* buf, size_t length)
 		{ if (client) client->write(buf, length); }
 
@@ -122,9 +136,10 @@ 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 String& s) { return publish(t, s.c_str(), s.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);
@@ -133,6 +148,7 @@ class MqttClient
 		// TODO seems to be useless
 		bool isLocal() const { return client == nullptr; }
 
+#ifdef TINY_MQTT_DEBUG
 		void dump()
 		{
 			Serial << "MqttClient (" << clientId.c_str() << ") p=" << (int32_t) parent
@@ -146,13 +162,13 @@ class MqttClient
 			}
 			Serial << "]" << endl;
 		}
-
+#endif
 
 	private:
 		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();
@@ -162,33 +178,18 @@ class MqttClient
 		uint32_t keep_alive;
 		uint32_t alive;
 		MqttMessage message;
+
+		// TODO	having a pointer on MqttBroker may produce larger binaries
+		// due to unecessary function linked if ever parent is not used
+		// (this is the case when MqttBroker isn't used except here)
 		MqttBroker* parent=nullptr;		// connection to local broker
+
 		WiFiClient* client=nullptr;		// connection to mqtt client or to remote broker
 		std::set<Topic>	subscriptions;
 		std::string clientId;
 		CallBack callback = nullptr;
 };
 
-/***********************************************
- * 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
- * R7 - allows all publish to go everywhere
- * ---------------------------------------------
- *  (*) single client or ip range
- * ---------------------------------------------
- *
- * ================================================+
- *              | connected     | not connected    |
- * -------------+---------------+------------------+
- * proxy broker | R2 R3 R5 R6   |    R5 R7         |
- * normal broker| R2 R3 R5 R6   | R1 R5 R7         |
- * -------------+---------------+------------------+
- *
- */
 class MqttBroker
 {
 	enum State
@@ -200,6 +201,7 @@ class MqttBroker
 	public:
 	  // TODO limit max number of clients
 		MqttBroker(uint16_t port);
+		~MqttBroker();
 
 		void begin() { server.begin(); }
 		void loop();
@@ -209,15 +211,17 @@ class MqttBroker
 		void connect(std::string host, uint32_t port=1883);
 		bool connected() const { return state == Connected; }
 
+#ifdef TINY_MQTT_DEBUG
 		void dump()
 		{
-			Serial << "broker: " << clients.size() << " client/s" << endl;
+			Serial << clients.size() << " client/s" << endl;
 			for(auto client: clients)
 			{
 				Serial << "  ";
 				client->dump();
 			}
 		}
+#endif
 
 	private:
 		friend class MqttClient;
@@ -229,7 +233,7 @@ 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);