MqttConnection.cpp

// Include the required headers
#include <ESP8266WiFi.h>
#include "MqttConnection.h"
#include "DataStructures.h"
#include <WiFiClientSecure.h>
#include <MQTT.h>

// create an instance of WifiClientSecure, and call it espClient
WiFiClientSecure espClient;

// create an instance of the MQTTClient called client, provide it with a buffer of 4096 bytes to handle incoming messages
MQTTClient client(4096);

void mqtt_connection::ensure_mqtt_connected(void(*callback)(String&, String&))
{ 
  if (client.connected()) {
    return;
  }
  
  //  set up an SSL fingerprint so that the secure client can verify the SSL cert of the MQTT broker
  espClient.setFingerprint(cfg_->mqtt.certificate);

  // tell the client the address of our broker, and provide it a wifi client (our secure client) to connect over
  client.begin(cfg_->mqtt.server, cfg_->mqtt.port, espClient);
	
  // pass a callback function to the client - which will call it for each message that's delivered over MQTT	
  client.onMessage(callback);

  // receiving loop
  while (!client.connected())
  {    
    Serial.print(F("Attempting MQTT connection..."));
    
    if (client.connect("tshirtHardware", cfg_->mqtt.user, cfg_->mqtt.password)) 
    {
      Serial.println(F("Connected."));
      client.subscribe(cfg_->mqtt.subscription);
    } 
    else 
    {
      Serial.println(F("Failed to connect to MQTT - Trying again in 5 seconds..."));
      delay(5000);
    }
  }
  
}

void mqtt_connection::process_messages()
{ 
	client.loop();
}

int mqtt_connection::publish(String message) 
{
	return client.publish(cfg_->mqtt.subscription, message);
}