Adafruit_MQTT_Library/examples/mqtt_esp8266_callback/mqtt_esp8266_callback.ino

/***************************************************
  Adafruit MQTT Library ESP8266 Example

  Must use ESP8266 Arduino from:
    https://github.com/esp8266/Arduino

  Works great with Adafruit's Huzzah ESP board:
  ----> https://www.adafruit.com/product/2471

  Adafruit invests time and resources providing this open source code,
  please support Adafruit and open-source hardware by purchasing
  products from Adafruit!

  Written by Tony DiCola for Adafruit Industries.
  MIT license, all text above must be included in any redistribution
 ****************************************************/
#include <ESP8266WiFi.h>
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"

/************************* WiFi Access Point *********************************/

#define WLAN_SSID       "network"
#define WLAN_PASS       "password"

/************************* Adafruit.io Setup *********************************/

#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  1883
#define AIO_USERNAME    "user"
#define AIO_KEY         "key"

/************ Global State (you don't need to change this!) ******************/

// Create an ESP8266 WiFiClient class to connect to the MQTT server.
WiFiClient client;

// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_USERNAME, AIO_KEY);

/****************************** Feeds ***************************************/

// Setup a feed called 'time' for subscribing to current time
Adafruit_MQTT_Subscribe timefeed = Adafruit_MQTT_Subscribe(&mqtt, "time/seconds");

// Setup a feed called 'slider' for subscribing to changes on the slider
Adafruit_MQTT_Subscribe slider = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/slider", MQTT_QOS_1);

// Setup a feed called 'onoff' for subscribing to changes to the button
Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/onoff", MQTT_QOS_1);

/*************************** Sketch Code ************************************/

int sec;
int min;
int hour;

int timeZone = -4; // utc-4 eastern daylight time (nyc)

void timecallback(uint32_t current) {

  // adjust to local time zone
  current += (timeZone * 60 * 60);

  // calculate current time
  sec = current % 60;
  current /= 60;
  min = current % 60;
  current /= 60;
  hour = current % 24;

  // print hour
  if(hour == 0 || hour == 12)
    Serial.print("12");
  if(hour < 12)
    Serial.print(hour);
  else
    Serial.print(hour - 12);

  // print mins
  Serial.print(":");
  if(min < 10) Serial.print("0");
  Serial.print(min);

  // print seconds
  Serial.print(":");
  if(sec < 10) Serial.print("0");
  Serial.print(sec);

  if(hour < 12)
    Serial.println(" am");
  else
    Serial.println(" pm");

}

void slidercallback(double x) {
  Serial.print("Hey we're in a slider callback, the slider value is: ");
  Serial.println(x);
}

void onoffcallback(char *data, uint16_t len) {
  Serial.print("Hey we're in a onoff callback, the button value is: ");
  Serial.println(data);
}


void setup() {
  Serial.begin(115200);
  delay(10);

  Serial.println(F("Adafruit MQTT demo"));

  // Connect to WiFi access point.
  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);
    Serial.print(".");
  }
  Serial.println();

  Serial.println("WiFi connected");
  Serial.println("IP address: "); Serial.println(WiFi.localIP());

  timefeed.setCallback(timecallback);
  slider.setCallback(slidercallback);
  onoffbutton.setCallback(onoffcallback);
  
  // Setup MQTT subscription for time feed.
  mqtt.subscribe(&timefeed);
  mqtt.subscribe(&slider);
  mqtt.subscribe(&onoffbutton);

}

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();

  // this is our 'wait for incoming subscription packets and callback em' busy subloop
  // try to spend your time here:
  mqtt.processPackets(10000);
  
  // ping the server to keep the mqtt connection alive
  // NOT required if you are publishing once every KEEPALIVE seconds
  
  if(! mqtt.ping()) {
    mqtt.disconnect();
  }
}

// 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... ");

  uint8_t retries = 3;
  while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
       Serial.println(mqtt.connectErrorString(ret));
       Serial.println("Retrying MQTT connection in 10 seconds...");
       mqtt.disconnect();
       delay(10000);  // wait 10 seconds
       retries--;
       if (retries == 0) {
         // basically die and wait for WDT to reset me
         while (1);
       }
  }
  Serial.println("MQTT Connected!");
}