[Question] How to get non null characteristic handles?

[Braincoke]

Hi,

Thanks for your work, I've just discovered this library and I spent quite some time trying to make it work.

Issue

I have setup an ESP-32 with ble-ctf and I am trying to use go-bluetooth to solve the CTF (to get acquainted with the library).
I managed to find my device, connect to it and get a list of characteristics but my handles are always equal to 0.

Code

Here is the gist of how I am using the library. I have a fully "working" snippet here

	// Display device characteristics
	chars, err := dev.GetCharacteristics()
	if err != nil {
		log.Error(err)
		os.Exit(5)
	}
	log.Infof("Found %d characteristics", len(chars))

	for _, char := range chars {
		// Uncomment to get the value
		// p := map[string]interface{}{}
		// char.ReadValue(p)
		charProps, _ := char.GetProperties()
		handle := charProps.Handle
		value := charProps.Value
		uuid := charProps.UUID

		// ISSUE : handle is always 0
		log.Infof("handle = %d, uuid = %s , value = %s", handle, uuid, hex.EncodeToString(value))
	}

I don't have the issue with gatttool:

gatttool -i hci0 -b B8:F0:09:C5:B5:2E --characteristics
handle = 0x0002, char properties = 0x20, char value handle = 0x0003, uuid = 00002a05-0000-1000-8000-00805f9b34fb
handle = 0x0015, char properties = 0x02, char value handle = 0x0016, uuid = 00002a00-0000-1000-8000-00805f9b34fb

What am I doing wrong? I have tried multiple variants like char.GetProperty("Handle") and so on but nothing works.

System information

OS : Ubuntu 20.04
Bluez version : 5.53
Go version : 1.16.2

[lia]

I have the same problem. Do you have a solution？

[Luca Capra]

I would suggest to check on dbus if it is actually returning the correct information. A tool like dfeet can help with a visual interface. If you find a solution would you like to share here so we can try to address with a fix?

Thank you