How to get the name of connected device over BLE?

Question

I am implementing a BLE peripheral in my firmware with Arduino ESP32.

When the central gets connected to it, I'd like to log the name of the central & its address.

How can I do that?

#include <BLEServer.h>
class ServerCallbacks: public BLEServerCallbacks {
 void onConnect(BLEServer* pServer) {
 ble.log("ServerCallbacks: Connected");
// ==> how can I add the connected device ID or name in the log?
 ble.deviceConnected = true;
 #if SUPPORT_LEDS_INDICATOR
 // === Show France flag colors
 // RGBW = 1,2,3, 4
 // CODE : BBWRR
 // CODE = 33411
 const String code = "BBWRR"; 
 ledIndicator.showAccessCode(code);
 #endif
 #if SUPPORT_BUZZER
 /// BLE connection jingle
 buzzer.playBleConnectedMelody();
 #endif
 };
 
 void onDisconnect(BLEServer* pServer) {
 ble.deviceConnected = false;
 ble.log("ServerCallbacks: Disconnected");
 #if SUPPORT_BUZZER
 /// BLE connection jingle
 buzzer.playBleDisconnectedMelody();
 #endif
 }
};
/// Somewhere in the setup:
server = BLEDevice::createServer();
 
// == Set up our calbacks
server->setCallbacks(new ServerCallbacks());

Answer 1

(Note: this is all just from reading the library source code, nothing has been tested).

You can't get the details of the just-connected-client. However you can get a list of the currently connected clients.

There is a function in the BLEServer class:

std::map<uint16_t, conn_status_t> getPeerDevices(bool client);

You can use that to get the list of connected clients. The "key" of the map is the connection id, and the "value" of the map is the "conn_status_t" struct, which includes a pointer to the peer device structure:

typedef struct {
 void *peer_device;
 bool connected;
 uint16_t mtu;
} conn_status_t;

You can keep your own list of "current" connection IDs and compare that to the "live" list when a new connection is made to find which is the new connection.

So you can take that peer_device pointer, cast it to a BLEClient pointer, then you call any of the normal BLEClient functions on that, including toString() which will return a string representation of the client.

That of course isn't the "name" of the client. I am not sure (not being an expert on BLE) how you get the name, but I think you may have to actively query it from the client, which should be perfectly possible now you have the BLEClient object pointer.

• anishsane: Sorry, but this does not look right to me. (Or it may have been changed after you posted the answer.) The peer_device points to the BLEserver object itself. So, we cannot just cast it to BLEClient See here: github.com/espressif/arduino-esp32/blob/master/libraries/BLE/…