pitrix/src/mqtt.h

#ifdef MQTT_ENABLE
PubSubClient mqtt_client(wifi);
long mqtt_last_reconnect_attempt = 0;

void mqtt_callback(char* complete_topic, byte* pl, unsigned int length) {
  pl[length] = '\0';
  char* payload = (char*)pl;
  char* topic = complete_topic + strlen(MQTT_TOPIC); // Strip MQTT_TOPIC from the beginning

  // Here, payload is a char* (but has to be casted).
  if(strcmp(topic, "mode")==0) {
    for (int i=0; i<NUM_EFFECTS; i++) {
      EffectEntry* e = &effects[i];
      if (strcmp(e->name, payload)==0) {
        //Serial.printf("Effect found in mqtt_callback: %p\n", (void *)&e->effect);
        current_effect = e->effect;
        clear();
        return;
      }
    }
  } else if (strcmp(topic, "reboot")==0) {
    ESP.restart();
  }

  long value = atol(payload);

  if (strcmp(topic, "brightness")==0 && value > 0 && value <= 255) {
    config_brightness = value;
    FastLED.setBrightness(config_brightness);
  } else if (strcmp(topic, "cycle_time")==0 && value > 0) {
    config_effect_cycle_time = value;
  }
}

boolean mqtt_connect() {
  char client_id[30];
  snprintf(client_id, 30, HOSTNAME, ESP.getChipId());
  LOG("MQTT * Connecting to MQTT server with client id "); LOGln(client_id);
  if (mqtt_client.connect(client_id, MQTT_USER, MQTT_PASS)) {
    LOGln("MQTT * Connected.");
    mqtt_client.publish(MQTT_TOPIC "status", "ONLINE");
    mqtt_client.subscribe(MQTT_TOPIC "+");
  }
  return mqtt_client.connected();
}

void mqtt_setup() {
  mqtt_client.setServer(MQTT_SERVER, MQTT_PORT);
  mqtt_client.setCallback(mqtt_callback);
  mqtt_last_reconnect_attempt = 0;
}

void mqtt_loop() {
  if (!mqtt_client.connected()) {
    long now = millis();
    if (now - mqtt_last_reconnect_attempt > 5000) {
      mqtt_last_reconnect_attempt = now;
      if (mqtt_connect()) {
        mqtt_last_reconnect_attempt = 0;
      }
    }
  } else {
    mqtt_client.loop();
  }
}
#endif // MQTT_ENABLE