device.uuids() returns a set of service UUID but then none discovered once connected

[mpiotrowski]

I am working on a project to connect ESP32 over bluetooth to a raspberry pi zero w. My ESP32 is going to be a basic server with a sensor that will notify the sensor data.

I was planning on using bluer as a raspberry client to automatically discover the ESP and connect on the notify characteristic. The discovery itself works fine, the devices are able to see each other but the problem occurs when I am actually trying to discover the right service. Following the gatt_client example this code actually gives me the service UUID I expect.

    let uuids = device.uuids().await?.unwrap_or_default();                                                                                                                                                                                                                                                                                                                                                                     
    println!("Discovered device {} with service UUIDs {:?}", addr, &uuids); 

However, later on when calling device.services() I receive an empty vector of services while device.app_properties() claims services were resolved.

I don't think I understand how to resolve this issue, any ideas greatly appreciated!

[surban]

device.uuids() returns the advertised services from the LE advertisement broadcast packet.

After connected to the device, device.services() returns the services described by the GATT attributes retrieved over the ATT protocol.

It is possible to include service UUIDs in the LE advertisement packet that are not present in the GATT table and vice versa.