notask-esp32.ino

#include <WiFi.h>

#include <espMqttClient.h>

#define WIFI_SSID "yourSSID"
#define WIFI_PASSWORD "yourpass"

#define MQTT_HOST IPAddress(192, 168, 1, 10)
#define MQTT_PORT 1883

espMqttClient mqttClient(espMqttClientTypes::UseInternalTask::NO);
bool reconnectMqtt = false;
uint32_t lastReconnect = 0;

void connectToWiFi() {
  Serial.println("Connecting to Wi-Fi...");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
}

void connectToMqtt() {
  Serial.println("Connecting to MQTT...");
  if (!mqttClient.connect()) {
    reconnectMqtt = true;
    lastReconnect = millis();
    Serial.println("Connecting failed.");
  } else {
    reconnectMqtt = false;
  }
}

void WiFiEvent(WiFiEvent_t event) {
  Serial.printf("[WiFi-event] event: %d\n", event);
  switch(event) {
  case ARDUINO_EVENT_WIFI_STA_GOT_IP:
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
    connectToMqtt();
    break;
  case ARDUINO_EVENT_WIFI_STA_DISCONNECTED:
    Serial.println("WiFi lost connection");
    break;
  default:
    break;
  }
}

void onMqttConnect(bool sessionPresent) {
  Serial.println("Connected to MQTT.");
  Serial.print("Session present: ");
  Serial.println(sessionPresent);
  uint16_t packetIdSub = mqttClient.subscribe("foo/bar", 2);
  Serial.print("Subscribing at QoS 2, packetId: ");
  Serial.println(packetIdSub);
  mqttClient.publish("foo/bar", 0, true, "test 1");
  Serial.println("Publishing at QoS 0");
  uint16_t packetIdPub1 = mqttClient.publish("foo/bar", 1, true, "test 2");
  Serial.print("Publishing at QoS 1, packetId: ");
  Serial.println(packetIdPub1);
  uint16_t packetIdPub2 = mqttClient.publish("foo/bar", 2, true, "test 3");
  Serial.print("Publishing at QoS 2, packetId: ");
  Serial.println(packetIdPub2);
}

void onMqttDisconnect(espMqttClientTypes::DisconnectReason reason) {
  Serial.printf("Disconnected from MQTT: %u.\n", static_cast<uint8_t>(reason));

  if (WiFi.isConnected()) {
    reconnectMqtt = true;
    lastReconnect = millis();
  }
}

void onMqttSubscribe(uint16_t packetId, const espMqttClientTypes::SubscribeReturncode* codes, size_t len) {
  Serial.println("Subscribe acknowledged.");
  Serial.print("  packetId: ");
  Serial.println(packetId);
  for (size_t i = 0; i < len; ++i) {
    Serial.print("  qos: ");
    Serial.println(static_cast<uint8_t>(codes[i]));
  }
}

void onMqttUnsubscribe(uint16_t packetId) {
  Serial.println("Unsubscribe acknowledged.");
  Serial.print("  packetId: ");
  Serial.println(packetId);
}

void onMqttMessage(const espMqttClientTypes::MessageProperties& properties, const char* topic, const uint8_t* payload, size_t len, size_t index, size_t total) {
  (void) payload;
  Serial.println("Publish received.");
  Serial.print("  topic: ");
  Serial.println(topic);
  Serial.print("  qos: ");
  Serial.println(properties.qos);
  Serial.print("  dup: ");
  Serial.println(properties.dup);
  Serial.print("  retain: ");
  Serial.println(properties.retain);
  Serial.print("  len: ");
  Serial.println(len);
  Serial.print("  index: ");
  Serial.println(index);
  Serial.print("  total: ");
  Serial.println(total);
}

void onMqttPublish(uint16_t packetId) {
  Serial.println("Publish acknowledged.");
  Serial.print("  packetId: ");
  Serial.println(packetId);
}

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.println();

  WiFi.persistent(false);
  WiFi.setAutoReconnect(true);
  WiFi.onEvent(WiFiEvent);

  mqttClient.onConnect(onMqttConnect);
  mqttClient.onDisconnect(onMqttDisconnect);
  mqttClient.onSubscribe(onMqttSubscribe);
  mqttClient.onUnsubscribe(onMqttUnsubscribe);
  mqttClient.onMessage(onMqttMessage);
  mqttClient.onPublish(onMqttPublish);
  mqttClient.setServer(MQTT_HOST, MQTT_PORT);

  connectToWiFi();
}

void loop() {
  static uint32_t currentMillis = 0;
  currentMillis = millis();

  if (reconnectMqtt && currentMillis - lastReconnect > 5000) {
    connectToMqtt();
  }

  // We used to option not to use the internal task
  // so we need to call the loop-method ourselves.
  // During connecting it may block.
  // Creating a separate task yourself is obviously
  // also a possibility.
  mqttClient.loop();
}