WebBluetooth connection issues

[pwilkowski]

Hello, I am trying to implement ble simple server with notify and write services. ESP32-S3

It seems to work well inside nrf connect (to check for debugging)

However when i try to connect via web bluetooth i seem to be getting error: NotSupportedError: GATT Error Unknown

as soon as i try to subscribe to notifications (i checked if i connect to correct control point and even tried to swap them)

this.ctrlChar = await btService.getCharacteristic(BluetoothTransport.CONTROL_POINT);
console.log(this.ctrlChar);
this.ctrlChar.addEventListener('characteristicvaluechanged', this.resolver.bind(this));
console.log(1);
await this.ctrlChar.startNotifications();

this my code for whole server:

#include "AppSerial.h"

BLEServer* pServer = NULL;
BLECharacteristic* pTxCharacteristic;
bool deviceConnected = false;
bool oldDeviceConnected = false;
uint8_t txValue = 0;

void bleLoop(void* p) {
    while (true) {
        if (deviceConnected) {
            pTxCharacteristic->setValue(&txValue, 1);
            pTxCharacteristic->notify();
            txValue++;
            delay(10);  // bluetooth stack will go into congestion, if too many packets are sent
        }

        // disconnecting
        if (!deviceConnected && oldDeviceConnected) {
            delay(500);                   // give the bluetooth stack the chance to get things ready
            bool success = pServer->startAdvertising();  // restart advertising
            Serial.print("start advertising: ");
            Serial.println(success ? "true" : "false");
            oldDeviceConnected = deviceConnected;
        }
        // connecting
        if (deviceConnected && !oldDeviceConnected) {
            // do stuff here on connecting
            oldDeviceConnected = deviceConnected;
        }
        delay(10);
    }
}

void bleSetup() {
    // Serial.begin(115200);

    // Create the BLE Device
    BLEDevice::init("UART Service");
    NimBLEDevice::setPower(ESP_PWR_LVL_P9);

    // Create the BLE Server
    pServer = BLEDevice::createServer();
    pServer->setCallbacks(new MyServerCallbacks());

    // Create the BLE Service
    BLEService* pService = pServer->createService(SERVICE_UUID);

    // Create a BLE Characteristic
    pTxCharacteristic = pService->createCharacteristic(
        CHARACTERISTIC_UUID_TX, NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::WRITE | NIMBLE_PROPERTY::NOTIFY
    );

    NimBLE2904* pBeef2904 = (NimBLE2904*)pTxCharacteristic->createDescriptor("2904");
    pBeef2904->setFormat(NimBLE2904::FORMAT_UTF8);

    BLECharacteristic* pRxCharacteristic =
        pService->createCharacteristic(CHARACTERISTIC_UUID_RX, NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::WRITE, 128);

    pRxCharacteristic->setCallbacks(new MyCallbacks());

    // Start the service
    pService->start();

    // Start the server
    pServer->start();

    NimBLEAdvertising* pAdvertising = NimBLEDevice::getAdvertising();
    pAdvertising->addServiceUUID(pService->getUUID());
    /** If your device is battery powered you may consider setting scan response
     *  to false as it will extend battery life at the expense of less data sent.
     */
    pAdvertising->setScanResponse(true);
    // Start advertising
    pAdvertising->start();

    Serial.println("Waiting a client connection to notify...");

    xTaskCreatePinnedToCore(bleLoop, "bleLoop", 8192, nullptr, 6, nullptr, ARDUINO_RUNNING_CORE);
}

void MyCallbacks::onWrite(BLECharacteristic* pCharacteristic) {
    std::string rxValue = pCharacteristic->getValue();

    if (rxValue.length() > 0) {
        Serial.println("*********");
        Serial.print("Received Value: ");
        for (int i = 0; i < rxValue.length(); i++) Serial.print(rxValue[i]);

        Serial.println();
        Serial.println("*********");
    }
}

void MyServerCallbacks::onConnect(BLEServer* pServer) {
    deviceConnected = true;
}

void MyServerCallbacks::onDisconnect(BLEServer* pServer) {
    deviceConnected = false;
}

what am i doing wrong?

[pwilkowski]

Nevermind, figured it out, if anyone stumbled upon this error, you should not create Descriptor for notify service, it's created automatically. So this code above works just delete those lines:

NimBLE2904* pBeef2904 = (NimBLE2904*)pTxCharacteristic->createDescriptor("2904");
    pBeef2904->setFormat(NimBLE2904::FORMAT_UTF8);