mhsw-espurna/code/espurna/uart_mqtt

#ifdef UARTtoMQTT

#include <queue>
#include <Ticker.h>

// -----------------------------------------------------------------------------
// GLOBALS TO THE MODULE
// -----------------------------------------------------------------------------
const byte numChars = 100;
char receivedChars[numChars]; // an array to store the received data
boolean newData = false;

void _recvWithEndMarker() {
  static byte ndx = 0;
  char endMarker = '\n';
  char rc;
 
  while (Serial.available() > 0 && newData == false) {
    rc = Serial.read();

    if (rc != endMarker) {
      receivedChars[ndx] = rc;
      ndx++;
      if (ndx >= numChars) {
        ndx = numChars - 1;
      }
    }
    else {
      receivedChars[ndx] = '\0'; // terminate the string
      ndx = 0;
      newData = true;
    }
  }
}

void _sendNewData() {
  if (newData == true && MQTT_SUPPORT) {
       mqttSend(MQTT_TOPIC_UARTIN, receivedChars); // publish: UART -> mqtt bus
    newData = false;
  }
}

#if MQTT_SUPPORT
void _UARTtoMQTTMqttCallback(unsigned int type, const char * topic, const char * payload) {
    if (type == MQTT_CONNECT_EVENT) {
        mqttSubscribe(MQTT_TOPIC_UARTOUT);
    }

    if (type == MQTT_MESSAGE_EVENT) {

        // Match topic
        String t = mqttTopicKey((char *) topic);
        bool isUARTOut = t.equals(MQTT_TOPIC_UARTOUT);

        if (isUARTOut) {
          Serial.print(payload);
          Serial.println();
        }

    }

}
#endif

// -----------------------------------------------------------------------------
// SETUP & LOOP
// -----------------------------------------------------------------------------

void UARTtoMQTTSetup() {

    #if MQTT_SUPPORT
        mqttRegister(_UARTtoMQTTMqttCallback);
    #endif

    // Register oop
    espurnaRegisterLoop(UARTtoMQTTLoop);

}

void UARTtoMQTTLoop() {
     _recvWithEndMarker();
     _sendNewData();
}

#endif