MQTT client rcommand completion

README.md

@@ -50,6 +50,9 @@ LoLin32lite + [LoraNode32-Lite shield](https://github.com/hallard/LoLin32-Lite-L
 - Generic ESP32
 
 Depending on board hardware following features are supported:
+- LoRaWAN communication, supporting various payload formats (see enclosed .js converters)
+- MQTT communication via TCP/IP and Ethernet interface (note: payload transmitted over MQTT will be base64 encoded)
+- SPI serial communication to a local host
 - LED (shows power & status)
 - OLED Display (shows detailed status)
 - RGB LED (shows colorized status)
@@ -62,7 +65,6 @@ Depending on board hardware following features are supported:
 - Switch external power / battery
 - LED Matrix display (similar to [this 64x16 model](https://www.instructables.com/id/64x16-RED-LED-Marquee/), can be ordered on [Aliexpress](https://www.aliexpress.com/item/P3-75-dot-matrix-led-module-3-75mm-high-clear-top1-for-text-display-304-60mm/32616683948.html))
 - SD-card (see section SD-card here) for logging pax data
-- Ethernet interface for MQTT communication via TCP/IP
 
 Target platform must be selected in `platformio.ini`.<br>
 Hardware dependent settings (pinout etc.) are stored in board files in /hal directory. If you want to use a ESP32 board which is not yet supported, use hal file generic.h and tailor pin mappings to your needs. Pull requests for new boards welcome.<br>

include/mqttclient.h

@@ -5,6 +5,7 @@
 #include "rcommand.h"
 #include <MQTT.h>
 #include <ETH.h>
+#include <mbedtls/base64.h>
 
 #ifndef MQTT_CLIENTNAME
 #define MQTT_CLIENTNAME clientId
@@ -17,8 +18,7 @@ uint32_t mqtt_queuewaiting(void);
 void mqtt_queuereset(void);
 void mqtt_client_task(void *param);
 int mqtt_connect(const char *my_host, const uint16_t my_port);
-void mqtt_callback(MQTTClient *client, char topic[], char payload[],
-                   int length);
+void mqtt_callback(MQTTClient *client, char *topic, char *payload, int length);
 void NetworkEvent(WiFiEvent_t event);
 esp_err_t mqtt_init(void);
 void mqtt_deinit(void);

src/mqttclient.cpp

@@ -1,7 +1,6 @@
 #ifdef HAS_MQTT
 
 #include "mqttclient.h"
-#include <base64.h>
 
 static const char TAG[] = __FILE__;
 
@@ -99,12 +98,20 @@ void mqtt_client_task(void *param) {
       // prepare mqtt topic
       char topic[16];
       snprintf(topic, 16, "%s/%u", MQTT_OUTTOPIC, msg.MessagePort);
+      size_t out_len = 0;
 
-      // send base64 encoded message to mqtt server and delete it from queue
-      if (mqttClient.publish(topic,
-                             base64::encode(msg.Message, msg.MessageSize))) {
-        ESP_LOGD(TAG, "%s/%s sent to MQTT server", topic,
-                 base64::encode(msg.Message, msg.MessageSize));
+      // get length of base64 encoded message
+      mbedtls_base64_encode(NULL, 0, &out_len, (unsigned char *)msg.Message,
+                            msg.MessageSize);
+
+      // base64 encode the message
+      unsigned char encoded[out_len];
+      mbedtls_base64_encode(encoded, out_len, &out_len,
+                            (unsigned char *)msg.Message, msg.MessageSize);
+
+      // send encoded message to mqtt server and delete it from queue
+      if (mqttClient.publish(topic, (const char *)encoded, out_len)) {
+        ESP_LOGD(TAG, "%u bytes sent to MQTT server", out_len);
         xQueueReceive(MQTTSendQueue, &msg, (TickType_t)0);
       } else
         ESP_LOGD(TAG, "Couldn't sent message to MQTT server");
@@ -117,19 +124,29 @@ void mqtt_client_task(void *param) {
   } // while (1)
 }
 
+// process incoming MQTT messages
+void mqtt_callback(MQTTClient *client, char *topic, char *payload, int length) {
+  if (strcmp(topic, MQTT_INTOPIC) == 0) {
+
+    // get length of base64 encoded message
+    size_t out_len = 0;
+    mbedtls_base64_decode(NULL, 0, &out_len, (unsigned char *)payload, length);
+
+    // decode the base64 message
+    unsigned char decoded[out_len];
+    mbedtls_base64_decode(decoded, out_len, &out_len, (unsigned char *)payload,
+                          length);
+
+    rcommand(decoded, out_len);
+  }
+}
+
 // enqueue outgoing messages in MQTT send queue
 void mqtt_enqueuedata(MessageBuffer_t *message) {
   if (xQueueSendToBack(MQTTSendQueue, (void *)message, (TickType_t)0) != pdTRUE)
     ESP_LOGW(TAG, "MQTT sendqueue is full");
 }
 
-// process incoming MQTT messages
-void mqtt_callback(MQTTClient *client, char topic[], char payload[],
-                   int length) {
-  if (strcmp(topic, MQTT_INTOPIC) == 0)
-    rcommand((const uint8_t *)payload, (const uint8_t)length);
-}
-
 void mqtt_queuereset(void) { xQueueReset(MQTTSendQueue); }
 
 uint32_t mqtt_queuewaiting(void) {