Add connected() function to MQTT class. Update examples with robust reconnect logic.

Adafruit_MQTT.h

@@ -66,7 +66,7 @@
 #define MQTT_CONN_KEEPALIVE 300
 
 // Largest full packet we're able to send.
-// Need to be able to store at least ~90 chars for a connect packet with full 
+// Need to be able to store at least ~90 chars for a connect packet with full
 // 23 char client ID.
 #define MAXBUFFERSIZE (105)
 
@@ -92,7 +92,7 @@ class Adafruit_MQTT_Subscribe;  // forward decl
 
 class Adafruit_MQTT {
  public:
-  Adafruit_MQTT(const char *server, uint16_t port, const char *cid, 
+  Adafruit_MQTT(const char *server, uint16_t port, const char *cid,
                 const char *user, const char *pass);
   virtual ~Adafruit_MQTT() {}
 
@@ -111,10 +111,13 @@ class Adafruit_MQTT {
   // otherwise.
   virtual bool disconnect() = 0;  // Subclasses need to fill this in!
 
+  // Return true if connected to the MQTT server, otherwise false.
+  virtual bool connected() = 0;  // Subclasses need to fill this in!
+
   // Publish a message to a topic using the specified QoS level.  Returns true
   // if the message was published, false otherwise.
   bool publish(const char *topic, char *payload, uint8_t qos);
-  
+
   // Add a subscription to receive messages for a topic.  Returns true if the
   // subscription could be added, false otherwise.
   bool subscribe(Adafruit_MQTT_Subscribe *sub);
@@ -173,7 +176,7 @@ class Adafruit_MQTT_Publish {
                                                 // This might be ignored and a higher precision value sent.
   bool publish(int32_t i);
   bool publish(uint32_t i);
- 
+
 private:
   Adafruit_MQTT *mqtt;
   const char *topic;

Adafruit_MQTT_CC3000.h

@@ -28,7 +28,7 @@
 
 
 // delay in ms between calls of available()
-#define MQTT_CC3000_INTERAVAILDELAY 10  
+#define MQTT_CC3000_INTERAVAILDELAY 10
 
 
 // CC3000-specific version of the Adafruit_MQTT class.
@@ -37,7 +37,7 @@
 // in the compilation of the library).
 class Adafruit_MQTT_CC3000 : public Adafruit_MQTT {
  public:
-  Adafruit_MQTT_CC3000(Adafruit_CC3000 *cc3k, const char *server, uint16_t port, 
+  Adafruit_MQTT_CC3000(Adafruit_CC3000 *cc3k, const char *server, uint16_t port,
                        const char *cid, const char *user, const char *pass):
     Adafruit_MQTT(server, port, cid, user, pass),
     cc3000(cc3k)
@@ -66,9 +66,9 @@ class Adafruit_MQTT_CC3000 : public Adafruit_MQTT {
         if (!dnsretries) return false;
         delay(500);
       }
-      
+
       serverip = ip;
-      cc3000->printIPdotsRev(serverip);  
+      cc3000->printIPdotsRev(serverip);
       Serial.println();
     }
 
@@ -77,15 +77,24 @@ class Adafruit_MQTT_CC3000 : public Adafruit_MQTT {
     // connect to server
     DEBUG_PRINTLN(F("Connecting to TCP"));
     mqttclient = cc3000->connectTCP(serverip, portnum);
-    
+
     return mqttclient.connected();
   }
 
   bool disconnect() {
-    return (mqttclient.close() == 0); 
+    if (connected()) {
+      return (mqttclient.close() == 0);
+    }
+    else {
+      return true;
+    }
   }
 
-  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout, 
+  bool connected() {
+    return mqttclient.connected();
+  }
+
+  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout,
                       bool checkForValidPubPacket = false) {
     /* Read data until either the connection is closed, or the idle timeout is reached. */
     uint16_t len = 0;
@@ -137,7 +146,7 @@ class Adafruit_MQTT_CC3000 : public Adafruit_MQTT {
     }
     return true;
   }
- 
+
  private:
   uint32_t serverip;
   Adafruit_CC3000 *cc3000;

Adafruit_MQTT_Client.cpp

@@ -34,13 +34,21 @@ bool Adafruit_MQTT_Client::connectServer() {
 }
 
 bool Adafruit_MQTT_Client::disconnect() {
-  // Stop connection and return success (stop has no indication of failure).
+  // Stop connection if connected and return success (stop has no indication of
-  client->stop();
+  // failure).
-  return true;  
+  if (client->connected()) {
+    client->stop();
+  }
+  return true;
+}
+
+bool Adafruit_MQTT_Client::connected() {
+  // Return true if connected, false if not connected.
+  return client->connected();
 }
 
 uint16_t Adafruit_MQTT_Client::readPacket(uint8_t *buffer, uint8_t maxlen,
-                                          int16_t timeout, 
+                                          int16_t timeout,
                                           bool checkForValidPubPacket) {
   /* Read data until either the connection is closed, or the idle timeout is reached. */
   uint16_t len = 0;

Adafruit_MQTT_Client.h

@@ -27,7 +27,7 @@
 
 
 // How long to delay waiting for new data to be available in readPacket.
-#define MQTT_CLIENT_READINTERVAL_MS 10  
+#define MQTT_CLIENT_READINTERVAL_MS 10
 
 
 // MQTT client implementation for a generic Arduino Client interface.  Can work
@@ -44,10 +44,11 @@ class Adafruit_MQTT_Client : public Adafruit_MQTT {
 
   bool connectServer();
   bool disconnect();
-  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout, 
+  bool connected();
+  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout,
                       bool checkForValidPubPacket = false);
   bool sendPacket(uint8_t *buffer, uint8_t len);
- 
+
  private:
   Client* client;
 };

Adafruit_MQTT_FONA.h

@@ -35,7 +35,7 @@
 // in the compilation of the library).
 class Adafruit_MQTT_FONA : public Adafruit_MQTT {
  public:
-  Adafruit_MQTT_FONA(Adafruit_FONA *f, const char *server, uint16_t port, 
+  Adafruit_MQTT_FONA(Adafruit_FONA *f, const char *server, uint16_t port,
                        const char *cid, const char *user, const char *pass):
     Adafruit_MQTT(server, port, cid, user, pass),
     fona(f)
@@ -55,7 +55,12 @@ class Adafruit_MQTT_FONA : public Adafruit_MQTT {
     return fona->TCPclose();
   }
 
-  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout, 
+  bool connected() {
+    // Return true if connected, false if not connected.
+    return fona->TCPconnected();
+  }
+
+  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout,
                       bool checkForValidPubPacket = false) {
     uint8_t *buffp = buffer;
     DEBUG_PRINTLN(F("Reading a packet.."));
@@ -72,7 +77,7 @@ class Adafruit_MQTT_FONA : public Adafruit_MQTT {
       DEBUG_PRINT('.');
       while (avail = fona->TCPavailable()) {
         DEBUG_PRINT('!');
-        
+
         if (len + avail > maxlen) {
 	  avail = maxlen - len;
 	  if (avail == 0) return len;
@@ -80,7 +85,7 @@ class Adafruit_MQTT_FONA : public Adafruit_MQTT {
 
         // try to read the data into the end of the pointer
         if (! fona->TCPread(buffp, avail)) return len;
-        
+
         // read it! advance pointer
         buffp += avail;
         len += avail;
@@ -103,14 +108,14 @@ class Adafruit_MQTT_FONA : public Adafruit_MQTT {
             return len;
           }
         }
-        
+
       }
       Watchdog.reset();
       timeout -= MQTT_FONA_INTERAVAILDELAY;
       timeout -= MQTT_FONA_QUERYDELAY; // this is how long it takes to query the FONA for avail()
       delay(MQTT_FONA_INTERAVAILDELAY);
     }
-    
+
     return len;
   }
 
@@ -127,9 +132,9 @@ class Adafruit_MQTT_FONA : public Adafruit_MQTT {
       DEBUG_PRINTLN(F("Connection failed!"));
       return false;
     }
-    return true;    
+    return true;
   }
- 
+
  private:
   uint32_t serverip;
   Adafruit_FONA *fona;

examples/mqtt_cc3k/mqtt_cc3k.ino

@@ -1,14 +1,14 @@
-/*************************************************** 
+/***************************************************
   Adafruit MQTT Library CC3000 Example
 
   Designed specifically to work with the Adafruit WiFi products:
   ----> https://www.adafruit.com/products/1469
 
-  Adafruit invests time and resources providing this open source code, 
+  Adafruit invests time and resources providing this open source code,
-  please support Adafruit and open-source hardware by purchasing 
+  please support Adafruit and open-source hardware by purchasing
   products from Adafruit!
 
-  Written by Limor Fried/Ladyada for Adafruit Industries.  
+  Written by Limor Fried/Ladyada for Adafruit Industries.
   MIT license, all text above must be included in any redistribution
  ****************************************************/
 #include <Adafruit_SleepyDog.h>
@@ -30,7 +30,7 @@
 
 #define WLAN_SSID       "...your SSID..."  // can't be longer than 32 characters!
 #define WLAN_PASS       "...your password..."
-#define WLAN_SECURITY   WLAN_SEC_WPA2  // Can be: WLAN_SEC_UNSEC, WLAN_SEC_WEP, 
+#define WLAN_SECURITY   WLAN_SEC_WPA2  // Can be: WLAN_SEC_UNSEC, WLAN_SEC_WEP,
                                        //         WLAN_SEC_WPA or WLAN_SEC_WPA2
 
 /************************* Adafruit.io Setup *********************************/
@@ -64,12 +64,12 @@ boolean CC3000connect(const char* wlan_ssid, const char* wlan_pass, uint8_t wlan
 
 /****************************** Feeds ***************************************/
 
-// Setup a feed called 'photocell' for publishing.  
+// Setup a feed called 'photocell' for publishing.
 // Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
 const char PHOTOCELL_FEED[] PROGMEM = AIO_USERNAME "/feeds/photocell";
 Adafruit_MQTT_Publish photocell = Adafruit_MQTT_Publish(&mqtt, PHOTOCELL_FEED);
 
-// Setup a feed called 'onoff' for subscribing to changes.  
+// Setup a feed called 'onoff' for subscribing to changes.
 const char ONOFF_FEED[] PROGMEM = AIO_USERNAME "/feeds/onoff";
 Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, ONOFF_FEED);
 
@@ -84,7 +84,7 @@ void setup() {
 
   // Initialise the CC3000 module
   Serial.print(F("\nInit the CC3000..."));
-  if (!cc3000.begin()) 
+  if (!cc3000.begin())
       halt("Failed");
 
   mqtt.subscribe(&onoffbutton);
@@ -93,31 +93,6 @@ void setup() {
     Serial.println(F("Retrying WiFi"));
     while(1);
   }
-
-  Serial.println(F("Connected to WiFi!"));
-  //////////////////////////////
-  Serial.println(F("Connecting to MQTT..."));
-  int8_t ret;
-  while ((ret = mqtt.connect()) != 0) {
-       switch (ret) {
-          case 1: Serial.println(F("Wrong protocol")); break;
-          case 2: Serial.println(F("ID rejected")); break;
-          case 3: Serial.println(F("Server unavail")); break;
-          case 4: Serial.println(F("Bad user/pass")); break;
-          case 5: Serial.println(F("Not authed")); break;
-          case 6: Serial.println(F("Failed to subscribe")); break;
-          default: {
-            Serial.println(F("Connection failed")); 
-            CC3000connect(WLAN_SSID, WLAN_PASS, WLAN_SECURITY);  // y0w, lets connect to wifi again
-            return;           // restart the loop
-          }
-       }
-       Serial.println(F("Retrying MQTT connection"));
-       delay(5000); 
-  }
-  //////////////////////////////
-
-  Serial.println(F("MQTT Connected!"));  
 }
 
 uint32_t x=0;
@@ -125,6 +100,11 @@ uint32_t x=0;
 void loop() {
   // Make sure to reset watchdog every loop iteration!
   Watchdog.reset();
+
+  // Ensure the connection to the MQTT server is alive (this will make the first
+  // connection and automatically reconnect when disconnected).  See the MQTT_connect
+  // function definition further below.
+  MQTT_connect();
  
   // Try to ping the MQTT server
   /*
@@ -140,13 +120,13 @@ void loop() {
   Adafruit_MQTT_Subscribe *subscription;
   while (subscription = mqtt.readSubscription(1000)) {
     if (subscription == &onoffbutton) {
-      Serial.print(F("Got: ")); 
+      Serial.print(F("Got: "));
       Serial.println((char *)onoffbutton.lastread);
     }
   }
-  
+
   // Now we can publish stuff!
-  Serial.print(F("\nSending photocell val ")); 
+  Serial.print(F("\nSending photocell val "));
   Serial.print(x);
   Serial.print("...");
   if (! photocell.publish(x++)) {
@@ -155,3 +135,35 @@ void loop() {
     Serial.println(F("OK!"));
   }
 }
+
+// Function to connect and reconnect as necessary to the MQTT server.
+// Should be called in the loop function and it will take care if connecting.
+void MQTT_connect() {
+  int8_t ret;
+
+  // Stop if already connected.
+  if (mqtt.connected()) {
+    return;
+  }
+
+  Serial.print("Connecting to MQTT... ");
+
+  while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
+       switch (ret) {
+          case 1: Serial.println("Wrong protocol"); break;
+          case 2: Serial.println("ID rejected"); break;
+          case 3: Serial.println("Server unavailable"); break;
+          case 4: Serial.println("Bad user/password"); break;
+          case 5: Serial.println("Not authenticated"); break;
+          case 6: Serial.println("Failed to subscribe"); break;
+          default:
+            Serial.println(F("Connection failed"));
+            CC3000connect(WLAN_SSID, WLAN_PASS, WLAN_SECURITY);  // y0w, lets connect to wifi again
+            break;
+       }
+       Serial.println("Retrying MQTT connection in 5 seconds...");
+       mqtt.disconnect();
+       delay(5000);  // wait 5 seconds
+  }
+  Serial.println("MQTT Connected!");
+}

examples/mqtt_esp8266/mqtt_esp8266.ino

@@ -1,4 +1,4 @@
-/*************************************************** 
+/***************************************************
   Adafruit MQTT Library ESP8266 Example
 
   Must use ESP8266 Arduino from:
@@ -7,11 +7,11 @@
   Works great with Adafruit's Huzzah ESP board:
   ----> https://www.adafruit.com/product/2471
 
-  Adafruit invests time and resources providing this open source code, 
+  Adafruit invests time and resources providing this open source code,
-  please support Adafruit and open-source hardware by purchasing 
+  please support Adafruit and open-source hardware by purchasing
   products from Adafruit!
 
-  Written by Tony DiCola for Adafruit Industries.  
+  Written by Tony DiCola for Adafruit Industries.
   MIT license, all text above must be included in any redistribution
  ****************************************************/
 #include <ESP8266WiFi.h>
@@ -47,12 +47,12 @@ Adafruit_MQTT_Client mqtt(&client, MQTT_SERVER, AIO_SERVERPORT, MQTT_CLIENTID, M
 
 /****************************** Feeds ***************************************/
 
-// Setup a feed called 'photocell' for publishing.  
+// Setup a feed called 'photocell' for publishing.
 // Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
 const char PHOTOCELL_FEED[] PROGMEM = AIO_USERNAME "/feeds/photocell";
 Adafruit_MQTT_Publish photocell = Adafruit_MQTT_Publish(&mqtt, PHOTOCELL_FEED);
 
-// Setup a feed called 'onoff' for subscribing to changes.  
+// Setup a feed called 'onoff' for subscribing to changes.
 const char ONOFF_FEED[] PROGMEM = AIO_USERNAME "/feeds/onoff";
 Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, ONOFF_FEED);
 
@@ -68,7 +68,7 @@ void setup() {
   Serial.println(); Serial.println();
   Serial.print("Connecting to ");
   Serial.println(WLAN_SSID);
-  
+
   WiFi.begin(WLAN_SSID, WLAN_PASS);
   while (WiFi.status() != WL_CONNECTED) {
     delay(500);
@@ -76,35 +76,21 @@ void setup() {
   }
   Serial.println();
 
-  Serial.println("WiFi connected");  
+  Serial.println("WiFi connected");
   Serial.println("IP address: "); Serial.println(WiFi.localIP());
 
   // Setup MQTT subscription for onoff feed.
   mqtt.subscribe(&onoffbutton);
-
-  // Connect to MQTT server.
-  Serial.println(F("Connecting to MQTT..."));
-  int8_t ret;
-  while ((ret = mqtt.connect()) != 0) {
-       switch (ret) {
-          case 1: Serial.println(F("Wrong protocol")); break;
-          case 2: Serial.println(F("ID rejected")); break;
-          case 3: Serial.println(F("Server unavail")); break;
-          case 4: Serial.println(F("Bad user/pass")); break;
-          case 5: Serial.println(F("Not authed")); break;
-          case 6: Serial.println(F("Failed to subscribe")); break;
-          default: Serial.println(F("Couldn't connect to MQTT server")); break;
-       }
-       Serial.println(F("Retrying MQTT connection"));
-       mqtt.disconnect();
-       delay(5000); 
-  }
-  Serial.println(F("MQTT Connected!"));
 }
 
 uint32_t x=0;
 
 void loop() {
+  // Ensure the connection to the MQTT server is alive (this will make the first
+  // connection and automatically reconnect when disconnected).  See the MQTT_connect
+  // function definition further below.
+  MQTT_connect();
+
   // Try to ping the MQTT server
   /*
   if (! mqtt.ping(3) ) {
@@ -117,13 +103,13 @@ void loop() {
   Adafruit_MQTT_Subscribe *subscription;
   while (subscription = mqtt.readSubscription(1000)) {
     if (subscription == &onoffbutton) {
-      Serial.print(F("Got: ")); 
+      Serial.print(F("Got: "));
       Serial.println((char *)onoffbutton.lastread);
     }
   }
-  
+
   // Now we can publish stuff!
-  Serial.print(F("\nSending photocell val ")); 
+  Serial.print(F("\nSending photocell val "));
   Serial.print(x);
   Serial.print("...");
   if (! photocell.publish(x++)) {
@@ -134,3 +120,34 @@ void loop() {
 
   delay(1000);
 }
+
+// Function to connect and reconnect as necessary to the MQTT server.
+// Should be called in the loop function and it will take care if connecting.
+void MQTT_connect() {
+  int8_t ret;
+
+  // Stop if already connected.
+  if (mqtt.connected()) {
+    return;
+  }
+
+  Serial.print("Connecting to MQTT... ");
+
+  while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
+       switch (ret) {
+          case 1: Serial.println("Wrong protocol"); break;
+          case 2: Serial.println("ID rejected"); break;
+          case 3: Serial.println("Server unavailable"); break;
+          case 4: Serial.println("Bad user/password"); break;
+          case 5: Serial.println("Not authenticated"); break;
+          case 6: Serial.println("Failed to subscribe"); break;
+          default: Serial.print("Couldn't connect to server, code: ");
+                   Serial.println(ret);
+                   break;
+       }
+       Serial.println("Retrying MQTT connection in 5 seconds...");
+       mqtt.disconnect();
+       delay(5000);  // wait 5 seconds
+  }
+  Serial.println("MQTT Connected!");
+}