BLEClient -> getServices() doesn't work

[GF65gh]

Hi, I'm working on a personal project to connect to a bluetooth enabled robot device and control it from an ESP32. Using a bluetooth app on my phone, I can connect to this device, access the service + characteristic I need, and write a value e.g. to change the color.

I'm working on a program based on the BLE Beacon Scanner example. I'm trying to connect to the service and characteric based on their UUID. The first issue I got is that the ESP32 doesn't see any service. advertisedDevice.haveServiceUUID() returns 0 and advertisedDevice.getServiceUUID() is null

Looking at my device on an iPhone app (LightBlue), it sees the robot device and it mentions "No services" below (or BlueCap app says Services: 0) When I connect to it, I can see and browse into 5 services, including the one I want to use. Opening this service, I have access to the 2 characteristics I want to use.

So I assume the solution involves using BLEClient::getServices yet running the program (see below) go until message "Client created, connecting..."

Is there a solution to loop on BLERemoteService items returned by getServices to use the appropriate service.

static BLEAdvertisedDevice* myDevice;
int scanTime = 5; //In seconds
BLEScan *pBLEScan;

class MyAdvertisedDeviceCallbacks : public BLEAdvertisedDeviceCallbacks
{
    void onResult(BLEAdvertisedDevice advertisedDevice)
    {
      if (advertisedDevice.haveName())
      {
        Serial.print("Device name: ");
        Serial.println(advertisedDevice.getName().c_str());        
        Serial.print("Address : ");        
        Serial.println(advertisedDevice.getAddress().toString().c_str());
        Serial.print("haveServiceUUID: "); Serial.println(advertisedDevice.haveServiceUUID());
        Serial.print("device's UUID: "); Serial.println(advertisedDevice.getServiceUUID().toString().c_str());
        //Connecting to client      
        BLEClient* pMyClient = BLEDevice::createClient(); 
        if (pMyClient == NULL) Serial.println("Unable to create client");
        else
        {
            Serial.print("Client created, connecting...");
            esp_ble_addr_type_t type = advertisedDevice.getAddressType(); 
            Serial.println("Server address type: " + String(type));
            delay(100);
            pMyClient->connect(advertisedDevice.getAddress(), type); 
            Serial.println("Client connected...");
            Serial.print("Nb of services  "); Serial.println(String(pMyClient->getServices()->size()));
            std::map<std::string, BLERemoteService*> *pRemoteServices = pMyClient->getServices();
            Serial.println("Getting services...");
        }     
      }
   }
};

void setup()
{
  Serial.begin(115200);
  Serial.println("Scanning...");
  BLEDevice::init("Controller");
  pBLEScan = BLEDevice::getScan(); //create new scan
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
  pBLEScan->setActiveScan(true); //active scan uses more power, but get results faster
  pBLEScan->setInterval(100);
  pBLEScan->setWindow(99); // less or equal setInterval value
}

void loop()
{
  // put your main code here, to run repeatedly:
  BLEScanResults foundDevices = pBLEScan->start(scanTime, false);
  Serial.print("Devices found: ");
  Serial.println(foundDevices.getCount());
  Serial.println("Scan done!");
  pBLEScan->clearResults(); // delete results fromBLEScan buffer to release memory
  delay(2000);
}

[chegewara]

Yes, it does not work the way you are doing it. Code is based on events and you cant perform some operations from withing an event. Follow examples.

[GF65gh]

Thank you, I used the BLE Client Test and getServices() works but I'm getting a size of 0. With the BlueCap app I use, I can see that my device has 5 UUIDs yet could these be not exposed as services and require a different access ?

`bool connectToServer() {
    Serial.print("Forming a connection to ");
    Serial.println(myDevice->getAddress().toString().c_str());    
    BLEClient*  pClient  = BLEDevice::createClient();
    Serial.println(" - Created client");
    pClient->setClientCallbacks(new MyClientCallback());
    // Connect to the remove BLE Server.
    pClient->connect(myDevice);  // if you pass BLEAdvertisedDevice instead of address, it will be recognized type of peer device address (public or private)
    Serial.println(" - Connected to server");

      //OK
      //Get Services
      std::map<std::string, BLERemoteService*> *pRemoteServices = pClient->getServices();
      Serial.print("Nb of services: "); Serial.println(pRemoteServices->size());`

[chegewara]

Maybe it is case similar to other one recently was reported. Solution was to add small delay between connect and get services.