update Code

libraries/PubSubClient/examples/mqtt_auth/mqtt_auth.ino

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+/*
+ Basic MQTT example with Authentication
+
+  - connects to an MQTT server, providing username
+    and password
+  - publishes "hello world" to the topic "outTopic"
+  - subscribes to the topic "inTopic"
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+#include <PubSubClient.h>
+
+// Update these with values suitable for your network.
+byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  // handle message arrived
+}
+
+EthernetClient ethClient;
+PubSubClient client(server, 1883, callback, ethClient);
+
+void setup()
+{
+  Ethernet.begin(mac, ip);
+  // Note - the default maximum packet size is 128 bytes. If the
+  // combined length of clientId, username and password exceed this,
+  // you will need to increase the value of MQTT_MAX_PACKET_SIZE in
+  // PubSubClient.h
+  
+  if (client.connect("arduinoClient", "testuser", "testpass")) {
+    client.publish("outTopic","hello world");
+    client.subscribe("inTopic");
+  }
+}
+
+void loop()
+{
+  client.loop();
+}

libraries/PubSubClient/examples/mqtt_basic/mqtt_basic.ino

@@ -0,0 +1,77 @@
+/*
+ Basic MQTT example
+
+ This sketch demonstrates the basic capabilities of the library.
+ It connects to an MQTT server then:
+  - publishes "hello world" to the topic "outTopic"
+  - subscribes to the topic "inTopic", printing out any messages
+    it receives. NB - it assumes the received payloads are strings not binary
+
+ It will reconnect to the server if the connection is lost using a blocking
+ reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
+ achieve the same result without blocking the main loop.
+ 
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+#include <PubSubClient.h>
+
+// Update these with values suitable for your network.
+byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  Serial.print("Message arrived [");
+  Serial.print(topic);
+  Serial.print("] ");
+  for (int i=0;i<length;i++) {
+    Serial.print((char)payload[i]);
+  }
+  Serial.println();
+}
+
+EthernetClient ethClient;
+PubSubClient client(ethClient);
+
+void reconnect() {
+  // Loop until we're reconnected
+  while (!client.connected()) {
+    Serial.print("Attempting MQTT connection...");
+    // Attempt to connect
+    if (client.connect("arduinoClient")) {
+      Serial.println("connected");
+      // Once connected, publish an announcement...
+      client.publish("outTopic","hello world");
+      // ... and resubscribe
+      client.subscribe("inTopic");
+    } else {
+      Serial.print("failed, rc=");
+      Serial.print(client.state());
+      Serial.println(" try again in 5 seconds");
+      // Wait 5 seconds before retrying
+      delay(5000);
+    }
+  }
+}
+
+void setup()
+{
+  Serial.begin(57600);
+
+  client.setServer(server, 1883);
+  client.setCallback(callback);
+
+  Ethernet.begin(mac, ip);
+  // Allow the hardware to sort itself out
+  delay(1500);
+}
+
+void loop()
+{
+  if (!client.connected()) {
+    reconnect();
+  }
+  client.loop();
+}

libraries/PubSubClient/examples/mqtt_esp8266/mqtt_esp8266.ino

@@ -0,0 +1,132 @@
+/*
+ Basic ESP8266 MQTT example
+
+ This sketch demonstrates the capabilities of the pubsub library in combination
+ with the ESP8266 board/library.
+
+ It connects to an MQTT server then:
+  - publishes "hello world" to the topic "outTopic" every two seconds
+  - subscribes to the topic "inTopic", printing out any messages
+    it receives. NB - it assumes the received payloads are strings not binary
+  - If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
+    else switch it off
+
+ It will reconnect to the server if the connection is lost using a blocking
+ reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
+ achieve the same result without blocking the main loop.
+
+ To install the ESP8266 board, (using Arduino 1.6.4+):
+  - Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
+       http://arduino.esp8266.com/stable/package_esp8266com_index.json
+  - Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
+  - Select your ESP8266 in "Tools -> Board"
+
+*/
+
+#include <ESP8266WiFi.h>
+#include <PubSubClient.h>
+
+// Update these with values suitable for your network.
+
+const char* ssid = "........";
+const char* password = "........";
+const char* mqtt_server = "broker.mqtt-dashboard.com";
+
+WiFiClient espClient;
+PubSubClient client(espClient);
+long lastMsg = 0;
+char msg[50];
+int value = 0;
+
+void setup_wifi() {
+
+  delay(10);
+  // We start by connecting to a WiFi network
+  Serial.println();
+  Serial.print("Connecting to ");
+  Serial.println(ssid);
+
+  WiFi.begin(ssid, password);
+
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+
+  randomSeed(micros());
+
+  Serial.println("");
+  Serial.println("WiFi connected");
+  Serial.println("IP address: ");
+  Serial.println(WiFi.localIP());
+}
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  Serial.print("Message arrived [");
+  Serial.print(topic);
+  Serial.print("] ");
+  for (int i = 0; i < length; i++) {
+    Serial.print((char)payload[i]);
+  }
+  Serial.println();
+
+  // Switch on the LED if an 1 was received as first character
+  if ((char)payload[0] == '1') {
+    digitalWrite(BUILTIN_LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
+    // but actually the LED is on; this is because
+    // it is active low on the ESP-01)
+  } else {
+    digitalWrite(BUILTIN_LED, HIGH);  // Turn the LED off by making the voltage HIGH
+  }
+
+}
+
+void reconnect() {
+  // Loop until we're reconnected
+  while (!client.connected()) {
+    Serial.print("Attempting MQTT connection...");
+    // Create a random client ID
+    String clientId = "ESP8266Client-";
+    clientId += String(random(0xffff), HEX);
+    // Attempt to connect
+    if (client.connect(clientId.c_str())) {
+      Serial.println("connected");
+      // Once connected, publish an announcement...
+      client.publish("outTopic", "hello world");
+      // ... and resubscribe
+      client.subscribe("inTopic");
+    } else {
+      Serial.print("failed, rc=");
+      Serial.print(client.state());
+      Serial.println(" try again in 5 seconds");
+      // Wait 5 seconds before retrying
+      delay(5000);
+    }
+  }
+}
+
+void setup() {
+  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
+  Serial.begin(115200);
+  setup_wifi();
+  client.setServer(mqtt_server, 1883);
+  client.setCallback(callback);
+}
+
+void loop() {
+
+  if (!client.connected()) {
+    reconnect();
+  }
+  client.loop();
+
+  long now = millis();
+  if (now - lastMsg > 2000) {
+    lastMsg = now;
+    ++value;
+    snprintf (msg, 50, "hello world #%ld", value);
+    Serial.print("Publish message: ");
+    Serial.println(msg);
+    client.publish("outTopic", msg);
+  }
+}

libraries/PubSubClient/examples/mqtt_large_message/mqtt_large_message.ino

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+/*
+ Long message ESP8266 MQTT example
+
+ This sketch demonstrates sending arbitrarily large messages in combination
+ with the ESP8266 board/library.
+
+ It connects to an MQTT server then:
+  - publishes "hello world" to the topic "outTopic"
+  - subscribes to the topic "greenBottles/#", printing out any messages
+    it receives. NB - it assumes the received payloads are strings not binary
+  - If the sub-topic is a number, it publishes a "greenBottles/lyrics" message
+    with a payload consisting of the lyrics to "10 green bottles", replacing
+    10 with the number given in the sub-topic.
+
+ It will reconnect to the server if the connection is lost using a blocking
+ reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
+ achieve the same result without blocking the main loop.
+
+ To install the ESP8266 board, (using Arduino 1.6.4+):
+  - Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
+       http://arduino.esp8266.com/stable/package_esp8266com_index.json
+  - Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
+  - Select your ESP8266 in "Tools -> Board"
+
+*/
+
+#include <ESP8266WiFi.h>
+#include <PubSubClient.h>
+
+// Update these with values suitable for your network.
+
+const char* ssid = "........";
+const char* password = "........";
+const char* mqtt_server = "broker.mqtt-dashboard.com";
+
+WiFiClient espClient;
+PubSubClient client(espClient);
+long lastMsg = 0;
+char msg[50];
+int value = 0;
+
+void setup_wifi() {
+
+  delay(10);
+  // We start by connecting to a WiFi network
+  Serial.println();
+  Serial.print("Connecting to ");
+  Serial.println(ssid);
+
+  WiFi.begin(ssid, password);
+
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+
+  randomSeed(micros());
+
+  Serial.println("");
+  Serial.println("WiFi connected");
+  Serial.println("IP address: ");
+  Serial.println(WiFi.localIP());
+}
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  Serial.print("Message arrived [");
+  Serial.print(topic);
+  Serial.print("] ");
+  for (int i = 0; i < length; i++) {
+    Serial.print((char)payload[i]);
+  }
+  Serial.println();
+
+  // Find out how many bottles we should generate lyrics for
+  String topicStr(topic);
+  int bottleCount = 0; // assume no bottles unless we correctly parse a value from the topic
+  if (topicStr.indexOf('/') >= 0) {
+    // The topic includes a '/', we'll try to read the number of bottles from just after that
+    topicStr.remove(0, topicStr.indexOf('/')+1);
+    // Now see if there's a number of bottles after the '/'
+    bottleCount = topicStr.toInt();
+  }
+
+  if (bottleCount > 0) {
+    // Work out how big our resulting message will be
+    int msgLen = 0;
+    for (int i = bottleCount; i > 0; i--) {
+      String numBottles(i);
+      msgLen += 2*numBottles.length();
+      if (i == 1) {
+        msgLen += 2*String(" green bottle, standing on the wall\n").length();
+      } else {
+        msgLen += 2*String(" green bottles, standing on the wall\n").length();
+      }
+      msgLen += String("And if one green bottle should accidentally fall\nThere'll be ").length();
+      switch (i) {
+      case 1:
+        msgLen += String("no green bottles, standing on the wall\n\n").length();
+        break;
+      case 2:
+        msgLen += String("1 green bottle, standing on the wall\n\n").length();
+        break;
+      default:
+        numBottles = i-1;
+        msgLen += numBottles.length();
+        msgLen += String(" green bottles, standing on the wall\n\n").length();
+        break;
+      };
+    }
+  
+    // Now we can start to publish the message
+    client.beginPublish("greenBottles/lyrics", msgLen, false);
+    for (int i = bottleCount; i > 0; i--) {
+      for (int j = 0; j < 2; j++) {
+        client.print(i);
+        if (i == 1) {
+          client.print(" green bottle, standing on the wall\n");
+        } else {
+          client.print(" green bottles, standing on the wall\n");
+        }
+      }
+      client.print("And if one green bottle should accidentally fall\nThere'll be ");
+      switch (i) {
+      case 1:
+        client.print("no green bottles, standing on the wall\n\n");
+        break;
+      case 2:
+        client.print("1 green bottle, standing on the wall\n\n");
+        break;
+      default:
+        client.print(i-1);
+        client.print(" green bottles, standing on the wall\n\n");
+        break;
+      };
+    }
+    // Now we're done!
+    client.endPublish();
+  }
+}
+
+void reconnect() {
+  // Loop until we're reconnected
+  while (!client.connected()) {
+    Serial.print("Attempting MQTT connection...");
+    // Create a random client ID
+    String clientId = "ESP8266Client-";
+    clientId += String(random(0xffff), HEX);
+    // Attempt to connect
+    if (client.connect(clientId.c_str())) {
+      Serial.println("connected");
+      // Once connected, publish an announcement...
+      client.publish("outTopic", "hello world");
+      // ... and resubscribe
+      client.subscribe("greenBottles/#");
+    } else {
+      Serial.print("failed, rc=");
+      Serial.print(client.state());
+      Serial.println(" try again in 5 seconds");
+      // Wait 5 seconds before retrying
+      delay(5000);
+    }
+  }
+}
+
+void setup() {
+  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
+  Serial.begin(115200);
+  setup_wifi();
+  client.setServer(mqtt_server, 1883);
+  client.setCallback(callback);
+}
+
+void loop() {
+
+  if (!client.connected()) {
+    reconnect();
+  }
+  client.loop();
+}

libraries/PubSubClient/examples/mqtt_publish_in_callback/mqtt_publish_in_callback.ino

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+/*
+ Publishing in the callback
+
+  - connects to an MQTT server
+  - subscribes to the topic "inTopic"
+  - when a message is received, republishes it to "outTopic"
+
+  This example shows how to publish messages within the
+  callback function. The callback function header needs to
+  be declared before the PubSubClient constructor and the
+  actual callback defined afterwards.
+  This ensures the client reference in the callback function
+  is valid.
+
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+#include <PubSubClient.h>
+
+// Update these with values suitable for your network.
+byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
+
+// Callback function header
+void callback(char* topic, byte* payload, unsigned int length);
+
+EthernetClient ethClient;
+PubSubClient client(server, 1883, callback, ethClient);
+
+// Callback function
+void callback(char* topic, byte* payload, unsigned int length) {
+  // In order to republish this payload, a copy must be made
+  // as the orignal payload buffer will be overwritten whilst
+  // constructing the PUBLISH packet.
+
+  // Allocate the correct amount of memory for the payload copy
+  byte* p = (byte*)malloc(length);
+  // Copy the payload to the new buffer
+  memcpy(p,payload,length);
+  client.publish("outTopic", p, length);
+  // Free the memory
+  free(p);
+}
+
+void setup()
+{
+
+  Ethernet.begin(mac, ip);
+  if (client.connect("arduinoClient")) {
+    client.publish("outTopic","hello world");
+    client.subscribe("inTopic");
+  }
+}
+
+void loop()
+{
+  client.loop();
+}

libraries/PubSubClient/examples/mqtt_reconnect_nonblocking/mqtt_reconnect_nonblocking.ino

@@ -0,0 +1,67 @@
+/*
+ Reconnecting MQTT example - non-blocking
+
+ This sketch demonstrates how to keep the client connected
+ using a non-blocking reconnect function. If the client loses
+ its connection, it attempts to reconnect every 5 seconds
+ without blocking the main loop.
+
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+#include <PubSubClient.h>
+
+// Update these with values suitable for your hardware/network.
+byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  // handle message arrived
+}
+
+EthernetClient ethClient;
+PubSubClient client(ethClient);
+
+long lastReconnectAttempt = 0;
+
+boolean reconnect() {
+  if (client.connect("arduinoClient")) {
+    // Once connected, publish an announcement...
+    client.publish("outTopic","hello world");
+    // ... and resubscribe
+    client.subscribe("inTopic");
+  }
+  return client.connected();
+}
+
+void setup()
+{
+  client.setServer(server, 1883);
+  client.setCallback(callback);
+
+  Ethernet.begin(mac, ip);
+  delay(1500);
+  lastReconnectAttempt = 0;
+}
+
+
+void loop()
+{
+  if (!client.connected()) {
+    long now = millis();
+    if (now - lastReconnectAttempt > 5000) {
+      lastReconnectAttempt = now;
+      // Attempt to reconnect
+      if (reconnect()) {
+        lastReconnectAttempt = 0;
+      }
+    }
+  } else {
+    // Client connected
+
+    client.loop();
+  }
+
+}

libraries/PubSubClient/examples/mqtt_stream/mqtt_stream.ino

@@ -0,0 +1,57 @@
+/*
+ Example of using a Stream object to store the message payload
+
+ Uses SRAM library: https://github.com/ennui2342/arduino-sram
+ but could use any Stream based class such as SD
+
+  - connects to an MQTT server
+  - publishes "hello world" to the topic "outTopic"
+  - subscribes to the topic "inTopic"
+*/
+
+#include <SPI.h>
+#include <Ethernet.h>
+#include <PubSubClient.h>
+#include <SRAM.h>
+
+// Update these with values suitable for your network.
+byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
+
+SRAM sram(4, SRAM_1024);
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  sram.seek(1);
+
+  // do something with the message
+  for(uint8_t i=0; i<length; i++) {
+    Serial.write(sram.read());
+  }
+  Serial.println();
+
+  // Reset position for the next message to be stored
+  sram.seek(1);
+}
+
+EthernetClient ethClient;
+PubSubClient client(server, 1883, callback, ethClient, sram);
+
+void setup()
+{
+  Ethernet.begin(mac, ip);
+  if (client.connect("arduinoClient")) {
+    client.publish("outTopic","hello world");
+    client.subscribe("inTopic");
+  }
+
+  sram.begin();
+  sram.seek(1);
+
+  Serial.begin(9600);
+}
+
+void loop()
+{
+  client.loop();
+}