thingsboard-client-sdk: Server-side RPC no longer working with ThingsBoard-arduino-sdk version 0.7.1

I’ve been evaluating serve-side RPC with ThingsBoard-arduino-sdk version 0.7.1 and an ESP32 development board with PlatformIO. I believe I have found a bug. When I test my code, which is heavily inspired on the ‘0002-arduino_rpc’ example, the ESP32 callbacks are never called although I can see that messages are being sent by the ThingsBoard platform.

After reviewing my code, I attempted to revert back to ThingsBoard-arduino-sdk version 0.6.0 and re-test my code, with minor changes using #define, at which point the RPC callbacks are working. See below for terminal debug messages confirming functionality:

Connecting to AP … Attempting to connect to WPA SSID: “YOUR_WIFI_AP” Connecting to: "THINGSBOARD_SERVER " with token “YOUR_ACCESS_TOKEN” Subscribing for RPC… Subscribe done [TB] Callback on_message from topic: v1/devices/me/rpc/request/1725 [TB] received RPC: [TB] example_set_temperature [TB] calling RPC: [TB] example_set_temperature [TB] params: [TB] {“state”:2} Received the set temperature RPC method [TB] response: [TB] {“example_response”:42}

From what I can see, server-side RPC is not working with ThingsBoard-arduino-sdk version 0.7.1 but is working with 0.6.0. Has anyone else seen this problem? More importantly, is there a solution? Please see my code below for additional details:

`// This sketch demonstrates connecting and receiving RPC calls from // ThingsBoard using ThingsBoard SDK. // // Hardware: // - ESP32

#include <Arduino.h> #include <ThingsBoard.h> #include <WiFi.h>

#define WIFI_AP “YOUR_WIFI_AP” #define WIFI_PASSWORD “YOUR_WIFI_PASSWORD”

// See https://thingsboard.io/docs/getting-started-guides/helloworld/ // to understand how to obtain an access token #define TOKEN “YOUR_ACCESS_TOKEN” #define THINGSBOARD_SERVER “thingsboard.cloud”

// Initialize the Ethernet client object WiFiClient espClient; // Initialize ThingsBoard instance ThingsBoard tb(espClient);

void setup() { // initialize serial for debugging Serial.begin(9600);

WiFi.config(INADDR_NONE, INADDR_NONE, INADDR_NONE); WiFi.setHostname(“MY_ESP32”); WiFi.begin(WIFI_AP, WIFI_PASSWORD); }

// Processes function for RPC call “example_set_temperature” // RPC_Data is a JSON variant, that can be queried using operator[] // See https://arduinojson.org/v5/api/jsonvariant/subscript/ for more details RPC_Response processTemperatureChange(const RPC_Data &data) { Serial.println(“Received the set temperature RPC method”);

// Just an response example return RPC_Response(“example_response”, 42); }

// Processes function for RPC call “example_set_switch” // RPC_Data is a JSON variant, that can be queried using operator[] // See https://arduinojson.org/v5/api/jsonvariant/subscript/ for more details RPC_Response processSwitchChange(const RPC_Data &data) { Serial.println(“Received the set switch method”);

// Just an response example return RPC_Response(“example_response”, 22.02); }

//#define THINGSBOARD_VERSION_060 #define THINGSBOARD_VERSION_07X

#ifdef THINGSBOARD_VERSION_060 const size_t callbacks_size = 2; RPC_Callback callbacks[callbacks_size] = { { “example_set_temperature”, processTemperatureChange }, { “example_set_switch”, processSwitchChange } }; #endif

#ifdef THINGSBOARD_VERSION_07X const std::vector<RPC_Callback> callbacks = { { “example_set_temperature”, processTemperatureChange }, { “example_set_switch”, processSwitchChange } }; #endif

bool subscribed = false;

void loop() { delay(100);

while(WiFi.status() != WL_CONNECTED) { Serial.println(“Connecting to AP …”); Serial.print("Attempting to connect to WPA SSID: "); Serial.println(WIFI_AP); delay(1000); }

if (!tb.connected()) { subscribed = false;

// Connect to the ThingsBoard
Serial.print("Connecting to: ");
Serial.print(THINGSBOARD_SERVER);
Serial.print(" with token ");
Serial.println(TOKEN);
if (!tb.connect(THINGSBOARD_SERVER, TOKEN)) {
  Serial.println("Failed to connect, retrying ...");
  return;
}

}

if (!subscribed) { Serial.println(“Subscribing for RPC…”);

#ifdef THINGSBOARD_VERSION_060
  if (!tb.RPC_Subscribe(callbacks, callbacks_size)) {
    Serial.println("Failed to subscribe for RPC");
    return;
  }
#endif

#ifdef THINGSBOARD_VERSION_07X
  if (!tb.RPC_Subscribe(callbacks.cbegin(), callbacks.cend())) {
    Serial.println("Failed to subscribe for RPC");
    return;
  }
#endif

Serial.println("Subscribe done");
subscribed = true;

}

tb.loop(); } `