Example when wifi is not connected

README.md

@@ -1,2 +1,14 @@
 # TinyMqtt
-ESP 8266 Small footprint Mqtt Broker and Client
+ESP 8266 is a very capable Mqtt Broker and Client
+
+Here are the features
+- mqtt client can Works without WiFi (local mode) in a unique ESP
+  Thus, publishes and subscribes are possible and allows
+  minimal (degraded) function of a single module.
+- broker can connect to another broker and becomes then a
+  proxy for clients that are connected to it.
+- zeroconf, this is a strange but very powerful mode
+  where each ESP is a a broker and scans the local network.
+  After a while one ESP becomes the 'master'
+  and all ESP are connected together. The master can die
+  whithout breaking the system.

examples/client-without-wifi/client-without-wifi.ino

@@ -0,0 +1,64 @@
+#include <TinyMqtt.h>   // https://github.com/hsaturn/TinyMqtt
+#include <Streaming.h>  // https://github.com/janelia-arduino/Streaming
+
+/** TinyMQTT allows a disconnected mode:
+ * 
+ *  In this example, local clients A and B are talking together, no need to be connected.
+ *  A single ESP can use this to be able to comunicate with itself with the power
+ *  of MQTT, and once connected still continue to work with others.
+ *  
+ */
+
+std::string topic="sensor/temperature";
+
+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 onPublishB(const Topic& topic, const char* payload, size_t length)
+{ Serial << "--> B Received " << topic.c_str() << endl; }
+
+void setup()
+{
+  Serial.begin(115200);
+  delay(500);
+  Serial << "init" << endl;
+
+  mqtt_a.setCallback(onPublishA);
+  mqtt_a.subscribe(topic);
+
+  mqtt_b.setCallback(onPublishB);
+  mqtt_b.subscribe(topic);
+}
+
+void loop()
+{
+	broker.loop();
+  mqtt_a.loop();
+  mqtt_b.loop();
+
+  // ============= client A publish ================
+	static const int intervalA = 5000;
+	static uint32_t timerA = millis() + intervalA;
+	
+	if (millis() > timerA)
+	{
+		Serial << "A is publishing " << topic.c_str() << endl;
+		timerA += intervalA;
+		mqtt_a.publish(topic);
+	}
+
+  // ============= client B publish ================
+	static const int intervalB = 3000;	// will send topic each 5000 ms
+	static uint32_t timerB = millis() + intervalB;
+	
+	if (millis() > timerB)
+	{
+		Serial << "B is publishing " << topic.c_str() << endl;
+		timerB += intervalB;
+		mqtt_b.publish(topic);
+	}
+}

examples/simple-broker/simple-broker.ino

@@ -16,7 +16,6 @@ void setup()
   WiFi.begin(ssid, password);
  
   while (WiFi.status() != WL_CONNECTED) {   
-    delay(500);
     Serial << '.';
     delay(500);
   }

examples/simple-client/simple-client.ino

@@ -0,0 +1,32 @@
+#include <ESP8266WiFi.h>
+#include "TinyMqtt.h"   // https://github.com/hsaturn/TinyMqtt
+#include <Streaming.h>  // https://github.com/janelia-arduino/Streaming
+
+const char *ssid = ;      // Put here your wifi SSID ("ssid")
+const char *password = ;  // Put here your Wifi password ("pwd")
+
+#define PORT 1883
+MqttBroker broker(PORT);
+
+void setup() 
+{
+  Serial.begin(115200);
+
+  WiFi.mode(WIFI_STA);
+  WiFi.begin(ssid, password);
+ 
+  while (WiFi.status() != WL_CONNECTED) {   
+    delay(500);
+    Serial << '.';
+    delay(500);
+  }
+  Serial << "Connected to " << ssid << "IP address: " << WiFi.localIP() << endl;  
+
+  broker.begin();
+  Serial << "Broker ready : " << WiFi.localIP() << " on port " << PORT << endl;
+}
+
+void loop()
+{
+  broker.loop();
+}

keywords.txt

@@ -3,16 +3,23 @@
 #######################################
 
 #######################################
-# Datatypes (KEYWORD1)
+# Datatypes and functions
 #######################################
 
+TinyMqtt    KEYWORD1
+
 MqttBroker  KEYWORD1
+begin				KEYWORD2
+loop				KEYWORD2
+
 MqttClient  KEYWORD1
+publish     KEYWORD2
+setCallback	KEYWORD2
+subscribe	  KEYWORD2
 
-#######################################
+Topic				KEYWORD1
-# Methods and Functions (KEYWORD2)
+matches			KEYWORD2
-#######################################
+c_str				KEYWORD2
-
 
 #######################################
 # Constants (LITERAL1)

library.json

@@ -6,7 +6,7 @@
         "type": "git",
         "url": "https://github.com/hsaturn/TinyMqtt.git"
     },
-    "version": "0.1",
+    "version": "0.2",
     "exclude": "",
     "examples": "examples/*/*.ino",
     "frameworks": "arduino",

library.properties

@@ -1,5 +1,5 @@
 name=TinyMqtt
-version=0.1
+version=0.2.0
 author=HSaturn <hsaturn@gmail.com>
 maintainer=HSaturn <hsaturn@gmail.com>
 sentence=A tiny broker and client library for MQTT messaging.
@@ -7,3 +7,4 @@ paragraph=MQTT is a lightweight messaging protocol ideal for small devices. This
 category=Communication
 url=https://github.com/hsaturn/TinyMqtt
 architectures=*
+includes=TinyMqtt.h

src/TinyMqtt.cpp

@@ -15,20 +15,29 @@ MqttBroker::MqttBroker(uint16_t port)
 {
 }
 
-MqttCnx::MqttCnx(MqttBroker* parent, WiFiClient& new_client)
+MqttClient::MqttClient(MqttBroker* parent, WiFiClient& new_client)
 	: parent(parent),
 	mqtt_connected(false)
 {
 	client = new_client ? new WiFiClient(new_client) : nullptr;
-	clientAlive();
+	alive = millis()+5000;	// client expires after 5s if no CONNECT msg
 }
 
-MqttCnx::~MqttCnx()
+MqttClient::MqttClient(MqttBroker* parent)
+	: parent(parent)
+{
+		client = nullptr;
+
+		parent->addClient(this);
+}
+
+MqttClient::~MqttClient()
 {
 	close();
+	parent->removeClient(this);
 }
 
-void MqttCnx::close()
+void MqttClient::close()
 {
 	if (client)
 	{
@@ -38,13 +47,32 @@ void MqttCnx::close()
 	}
 }
 
+void MqttBroker::addClient(MqttClient* client)
+{
+		clients.push_back(client);
+}
+
+void MqttBroker::removeClient(MqttClient* remove)
+{
+  for(auto it=clients.begin(); it!=clients.end(); it++)
+	{
+		auto client=*it;
+		if (client==remove)
+		{
+			clients.erase(it);
+			return;
+		}
+	}
+	Serial << "Error cannot remove client" << endl;	// TODO should not occur
+}
+
 void MqttBroker::loop()
 {
   WiFiClient client = server.available();
   
   if (client)
 	{
-		clients.push_back(new MqttCnx(this, client));
+		addClient(new MqttClient(this, client));
 		Serial << "New client (" << clients.size() << ')' << endl;
 	}
 
@@ -58,17 +86,36 @@ void MqttBroker::loop()
 		else
 		{
       Serial << "Client " << client->id().c_str() << "  Disconnected" << endl;
-			clients.erase(it);
+			// Note: deleting a client not added by the broker itself will probably crash later.
 			delete client;
 			break;
     }
 	}
 }
 
-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)
 {
 	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(
@@ -87,7 +134,7 @@ void MqttMessage::getString(char* &buffer, uint16_t& len)
 	buffer+=2;
 }
 
-void MqttCnx::clientAlive()
+void MqttClient::clientAlive()
 {
 	if (keep_alive)
 	{
@@ -97,7 +144,7 @@ void MqttCnx::clientAlive()
 		alive=0;
 }
 
-void MqttCnx::loop()
+void MqttClient::loop()
 {
 	if (alive && (millis() > alive))
 	{
@@ -115,7 +162,7 @@ void MqttCnx::loop()
 	}
 }
 
-void MqttCnx::processMessage()
+void MqttClient::processMessage()
 {
 	std::string error;
 	std::string s;
@@ -186,7 +233,7 @@ void MqttCnx::processMessage()
 			message.getString(payload, len);	// Topic
 			outstring("Subscribes", payload, len);
 
-			subscriptions.insert(Topic(payload, len));
+			subscribe(Topic(payload, len));
 			bclose = false;
 			// TODO SUBACK
 			break;
@@ -205,7 +252,7 @@ void MqttCnx::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;
 			}
@@ -241,15 +288,36 @@ bool Topic::matches(const Topic& topic) const
 	return false;
 }
 
-void MqttCnx::publish(const Topic& topic, MqttMessage& msg)
+// publish from local client
+void MqttClient::publish(const Topic& topic, const char* payload, size_t pay_length)
+{
+	message.create(MqttMessage::Publish);
+	message.add(topic);
+	message.add(payload, pay_length);
+	if (parent)
+		parent->publish(this, topic, message);
+	else if (client)
+		publish(topic, message);
+	else
+		Serial << "  Should not happen" << endl;
+}
+
+// republish a received publish if it matches any in subscriptions
+void MqttClient::publish(const Topic& topic, MqttMessage& msg)
 {
 	for(const auto& subscription: subscriptions)
 	{
 		if (subscription.matches(topic))
 		{
-			// Serial << "Republishing " << topic.str().c_str() << " to " << clientId.c_str() << endl;
+			if (client)
+			{
 				msg.sendTo(this);
 			}
+			else if (callback)
+			{
+				callback(topic, nullptr, 0);	// TODO 
+			}
+		}
 	}
 }
 
@@ -311,6 +379,11 @@ void MqttMessage::incoming(char in_byte)
 	}
 }
 
+void MqttMessage::add(const char* p, size_t len)
+{
+	while(len--) incoming(*p);
+}
+
 void MqttMessage::encodeLength(char* msb, int length)
 {
 	do
@@ -322,7 +395,7 @@ void MqttMessage::encodeLength(char* msb, int length)
 	} while (length);
 };
 
-void MqttMessage::sendTo(MqttCnx* client)
+void MqttMessage::sendTo(MqttClient* client)
 {
 	if (curr-buffer-2 >= 0)
 	{

src/TinyMqtt.h

@@ -11,11 +11,14 @@ class Topic : public IndexedString
 	public:
 		Topic(const char* s, uint8_t len) : IndexedString(s,len){}
 		Topic(const char* s) : Topic(s, strlen(s)) {}
+		Topic(const std::string s) : Topic(s.c_str(), s.length()){};
+
+		const char* c_str() const { return str().c_str(); }
 
 		bool matches(const Topic&) const;
 };
 
-class MqttCnx;
+class MqttClient;
 class MqttMessage
 {
 	public:
@@ -45,6 +48,9 @@ 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 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; }
@@ -69,7 +75,7 @@ class MqttMessage
 			size=0;
 			state=Create;
 		}
-		void sendTo(MqttCnx*);
+		void sendTo(MqttClient*);
 		void hexdump(const char* prefix=nullptr) const;
 
 	private:
@@ -83,8 +89,9 @@ class MqttMessage
 };
 
 class MqttBroker;
-class MqttCnx
+class MqttClient
 {
+	using CallBack = void (*)(const Topic& topic, const char* payload, size_t payload_length);
 	enum Flags
 	{
 		FlagUserName = 128,
@@ -96,11 +103,11 @@ class MqttCnx
 		FlagReserved = 1
 	};
 	public:
-		MqttCnx(MqttBroker* parent, WiFiClient& client);
+		MqttClient(MqttBroker*);
 
-		~MqttCnx();
+		~MqttClient();
 
-		bool connected() { return client && client->connected(); }
+		bool connected() { return client==nullptr || client->connected(); }
 		void write(const char* buf, size_t length)
 		{ if (client) client->write(buf, length); }
 
@@ -108,9 +115,24 @@ class MqttCnx
 
 		void loop();
 		void close();
-		void publish(const Topic& topic, MqttMessage& msg);
+		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);};
+
+		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);
+		// republish a received publish if topic matches any in subscriptions
+		void publish(const Topic& topic, MqttMessage& msg);
+
 		void clientAlive();
 		void processMessage();
 
@@ -118,43 +140,75 @@ class MqttCnx
 		uint32_t keep_alive;
 		uint32_t alive;
 		bool mqtt_connected;
-		WiFiClient* client;
+		WiFiClient* client;		// nullptr if this client is local
 		MqttMessage message;
 		MqttBroker* parent;
 		std::set<Topic>	subscriptions;
 		std::string clientId;
+		CallBack callback;
 };
 
-class MqttClient
+/***********************************************
-{
+ * R1 - accept external cnx
-	public:
+ * R2 - allows all clients pusblish to go outside
-		MqttClient(IPAddress broker) : broker_ip(broker) {}
+ * R3 - allows ext publish to all clients
-
+ * R4 - allows local publish to local clients
-	protected:
+ * R5 - tries to connect elsewhere (*)
-		IPAddress broker_ip;
+ * 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);
 
 		void begin() { server.begin(); }
 		void loop();
 
+		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;
+
 		bool checkUser(const char* user, uint8_t len) const
 		{ return compareString(auth_user, user, len); }
 
 		bool checkPassword(const char* password, uint8_t len) const
 		{ return compareString(auth_password, password, len); }
 
-		void publish(const Topic& topic, MqttMessage& msg);
 
-	private:
+		void publish(const MqttClient* source, const Topic& topic, MqttMessage& msg);
+
+		// For clients that are added not by the broker itself
+		void addClient(MqttClient* client);
+		void removeClient(MqttClient* client);
+
 		bool compareString(const char* good, const char* str, uint8_t str_len) const;
-		std::vector<MqttCnx*>	clients;
+		std::vector<MqttClient*>	clients;
 		WiFiServer server;
 
 		const char* auth_user = "guest";
 		const char* auth_password = "guest";
+		State state = Disconnected;
+
+		MqttClient* broker = nullptr;
 };