PubSubClient sample for ESP8266 Arduino

esp8266_pubsubclient.ino

#include <PubSubClient.h>
#include <ESP8266WiFi.h>

const char* ssid = ".................";
const char* password = "................";

char* topic = "esp8266_arduino_out";
char* server = "iot.eclipse.org";


WiFiClient wifiClient;
PubSubClient client(server, 1883, callback, wifiClient);

void callback(char* topic, byte* payload, unsigned int length) {
  // handle message arrived
}


String macToStr(const uint8_t* mac)
{
  String result;
  for (int i = 0; i < 6; ++i) {
    result += String(mac[i], 16);
    if (i < 5)
      result += ':';
  }
  return result;
}

void setup() {
  Serial.begin(115200);
  delay(10);
  
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

  // Generate client name based on MAC address and last 8 bits of microsecond counter
  String clientName;
  clientName += "esp8266-";
  uint8_t mac[6];
  WiFi.macAddress(mac);
  clientName += macToStr(mac);
  clientName += "-";
  clientName += String(micros() & 0xff, 16);

  Serial.print("Connecting to ");
  Serial.print(server);
  Serial.print(" as ");
  Serial.println(clientName);
  
  if (client.connect((char*) clientName.c_str())) {
    Serial.println("Connected to MQTT broker");
    Serial.print("Topic is: ");
    Serial.println(topic);
    
    if (client.publish(topic, "hello from ESP8266")) {
      Serial.println("Publish ok");
    }
    else {
      Serial.println("Publish failed");
    }
  }
  else {
    Serial.println("MQTT connect failed");
    Serial.println("Will reset and try again...");
    abort();
  }
}

void loop() {
  static int counter = 0;
  
  String payload = "{\"micros\":";
  payload += micros();
  payload += ",\"counter\":";
  payload += counter;
  payload += "}";
  
  if (client.connected()){
    Serial.print("Sending payload: ");
    Serial.println(payload);
    
    if (client.publish(topic, (char*) payload.c_str())) {
      Serial.println("Publish ok");
    }
    else {
      Serial.println("Publish failed");
    }
  }
  ++counter;
  delay(5000);
}

Compilation failed with arduino ide, had to move the void callback above PubSubClient, but it should be fine as Naish21 mentioned above aswell..

Has anyone got this working with connection to port 8883 with username/pass/TLS etc ?

@AdamMiltonBarker - I've been trying and keep getting
"Attempting MQTT connection...failed, rc=-2 try again in 5 seconds"

Thanks Naish21 for your advice.

I downloaded my version of Mosquitto (v0.15) direct from the rasperian wheezy library & it was failing. When I wised up and downloaded Mosquitto from the Debian library (Latest version) all was goodness.

So if you have followed the instructions above and are still not connecting, try checking your Mosquitto version - you need the latest as the old ones done work

Instructions here
[(http://mosquitto.org/2013/01/mosquitto-debian-repository/)]

i have used esp 12e pubsub client. i will sent the message through mqtt using ardunio ide 1,6.5.once upload my code with iot.eclipse.org mqtt server url means data will send . so i change my own mqtt server means message not send it show the error
WiFi connected
IP address:
192.168.100.49
Attempting MQTT connection...failed, rc=-2 try again in 5 seconds

give me any suggestion pls?

Thank you. It works good.
Mosquitto Mqtt broker is on Ubuntu 12.04
I monitor the esp8266 through COM port /dev/ttyUSB0.
I have changed just this:
const char* ssid = "ququ2";
const char* password = "george34";
char* topic = "home/motions/Holl";
char* server = "192.168.1.19";