MQTT_Basic

#include <WiFi.h>
#include <PubSubClient.h>
 
/* reference https://youtu.be/5tG3JXFYrUo von Ali Panjaitan
*/
const char* ssid="SSID";
const char* pass="password";
const char* brokerUser = "user";
const char* brokerPass = "password";
const char* broker = "mqtt.dioty.co";
const char* outTopic ="/out";
const char* inTopic ="/in";
char Recdata[100]; 
String response;
WiFiClient espClient;
PubSubClient client(espClient);
long currentTime, lastTime;
int count = 0;
char messages[50];
int LED = 18;
void setupWifi(){
  delay(100);
  Serial.print("\nConnecting to");
  Serial.println(ssid);
 
  WiFi.begin(ssid, pass);
 
  while(WiFi.status() != WL_CONNECTED) {
    delay(100);
    Serial.print("-");
  }
 
  Serial.print("\nConnected to ");
  Serial.println(ssid);
}
 
void reconnect(){
  while(!client.connected()){
    Serial.print("\nConncting to ");
    Serial.println(broker);
    if(client.connect("esp32", brokerUser, brokerPass)){
      Serial.print("\nConnected to ");
      Serial.println(broker);
      client.subscribe(inTopic);
    } else {
      Serial.println("\n Trying to reconnect");
      delay(5000);
    }
  }
}
 
void callback(char* topic, byte* payload, unsigned int length){
  
  Serial.print("Message received : ");
//  Serial.println(topic);
  for(int i=0; i<length; i++){
    response += (char)payload[i];
  }
  Serial.println(response);

  if(response == "on")  // Turn the light on
  {
    digitalWrite(LED, HIGH);
    response = "";
  }
  else if(response == "off")  // Turn the light off
  {
    digitalWrite(LED, LOW);
    response = "";
  }
}
 
void setup() {
    // put your setup code here, to run once:
    Serial.begin(115200);
    setupWifi();
    client.setServer(broker, 1883);
    client.setCallback(callback);
    pinMode(18, OUTPUT);
}
 
void loop() {
    // put your main code here, to run repeatedly:
    if (!client.connected()){
      reconnect();
    }
  client.loop();
 
//  currentTime = millis();
//  if(currentTime - lastTime > 2000){
//    count++;
//    snprintf(messages, 75, "Count: %ld", count);
//    Serial.print("Sending Messages: ");
//    Serial.println(messages);
//    client.publish(outTopic, messages);
//    lastTime = millis();
//  }
}