listeningdaemon/arduino/MQTT/MQTT.ino

// Board: WiFiduino

#include <ArduinoMqttClient.h>
// #include <WiFiNINA.h>
#include <ESP8266WiFi.h>
// #include "arduino_secrets.h"
#include <PubSubClient.h>

///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = VITRINE_SSID;           // your network SSID
char password[] = VITRINE_WIFI_PASS;  // your network password

WiFiClient espClient;
MqttClient mqttClient(espClient);
PubSubClient mqtt_client(espClient);


const char broker[] = "mqtt.klank.school";
int port = 8883;
const char topic[] = "real_unique_topic";
const char topic2[] = "real_unique_topic_2";
const char topic3[] = "real_unique_topic_3";
const char *mqtt_topic = "emqx/esp8266/led";  //
const char *mqtt_username = MQTT_ARDUINO_USERNAME;
const char *mqtt_password = MQTT_ARDUINO_PASS;

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ;  // wait for serial port to connect. Needed for native USB port only
  }
  // attempt to connect to Wifi network:
  Serial.print("Attempting to connect to SSID: ");
  // WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.println(". stil not");
  }

  Serial.println("You're connected to the network");
  Serial.println();

  Serial.print("Attempting to connect to the MQTT broker: ");
  Serial.println(broker);

   while (!mqtt_client.connected()) {
      String client_id = "esp8266-client-" + String(WiFi.macAddress());
      Serial.printf("Connecting to MQTT Broker as %s.....\n", client_id.c_str());
      if (mqtt_client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
          Serial.println("Connected to MQTT broker");
          mqtt_client.subscribe(mqtt_topic);
          // Publish message upon successful connection
          mqtt_client.publish(mqtt_topic, "Hi EMQX I'm ESP8266 ^^");
      } else {
          Serial.print("Failed to connect to MQTT broker, rc=");
          Serial.print(mqtt_client.state());
          Serial.println(" try again in 5 seconds");
          delay(5000);
      }
  }

  Serial.println("You're connected to the MQTT broker!");
  Serial.println();

  // set the message receive callback
  mqttClient.onMessage(onMqttMessage);

  Serial.print("Subscribing to topic: ");
  Serial.println(topic);
  Serial.println();

  // subscribe to a topic
  mqttClient.subscribe(topic);
  mqttClient.subscribe(topic2);
  mqttClient.subscribe(topic3);

  // topics can be unsubscribed using:
  // mqttClient.unsubscribe(topic);

  Serial.print("Topic: ");
  Serial.println(topic);
  Serial.print("Topic: ");
  Serial.println(topic2);
  Serial.print("Topic: ");
  Serial.println(topic3);

  Serial.println();
}

void loop() {
  // call poll() regularly to allow the library to receive MQTT messages and
  // send MQTT keep alive which avoids being disconnected by the broker
  mqttClient.poll();
}

void onMqttMessage(int messageSize) {
  // we received a message, print out the topic and contents
  Serial.println("Received a message with topic '");
  Serial.print(mqttClient.messageTopic());
  Serial.print("', length ");
  Serial.print(messageSize);
  Serial.println(" bytes:");

  // use the Stream interface to print the contents
  while (mqttClient.available()) {
    Serial.print((char)mqttClient.read());
  }
  Serial.println();
  Serial.println();
}