switching

  for (int i = 0; i < length; i++) {
    Serial.print((char)message[i]);
    messageTemp += (char)message[i];
  }
  Serial.println();

  // Feel free to add more if statements to control more GPIOs with MQTT

  // If a message is received on the topic home/office/sonoff01X, you check if the message is either 1 or 0. Turns the ESP GPIO according to the message
  if(topic=="home/office/sonoff01X"){
      Serial.print("Changing sonoff01X to ");
      if(messageTemp == "on"){
        digitalWrite(gpio13Led, LOW);
        digitalWrite(gpio12Relay, HIGH);
        Serial.print("On");
        client.publish("home/office/sonoff01X/state","on");
      }
      else if(messageTemp == "off"){
        digitalWrite(gpio13Led, HIGH);
        digitalWrite(gpio12Relay, LOW);
        Serial.print("Off");
       client.publish("home/office/sonoff01X/state","off");
      }
  }
  Serial.println();
}