signature "" on interface ... doesnt exist

• bleak version: 0.3
• Python version: 3.6
• Operating System: Ubuntu

Description

I want to connect to an BLE device.

What I Did

Traceback (most recent call last):
  File "/home/jonas/Schreibtisch/TMRTFlib.py", line 572, in <module>
    loop.run_until_complete(connect_device_bleak(address, loop))
  File "/usr/lib/python3.6/asyncio/base_events.py", line 473, in run_until_complete
    return future.result()
  File "/home/jonas/Schreibtisch/TMRTFlib.py", line 552, in connect_device_bleak
    async with BleakClient(address, loop=loop) as client:
  File "/home/jonas/.local/lib/python3.6/site-packages/bleak/backends/client.py", line 35, in __aenter__
    await self.connect()
  File "/home/jonas/.local/lib/python3.6/site-packages/bleak/backends/bluezdbus/client.py", line 76, in connect
    raise BleakError(str(e))
bleak.exc.BleakError: org.freedesktop.DBus.Error.UnknownObject: Method "Connect" with signature "" on interface "org.bluez.Device1" doesn't exist

[hbldh]

I also got this error when I tried at first. Then I performed a discovery operation first (see discover example), and after that it works. It’s like the DBus interface must be “started” and have stored a entry about the peripheral you want to connect to.

Try this and it it works I will add a discover action when connect is called.

[karlp]

I’m getting this still with bluez 5.64 on openwrt (dbus, but not systemd) using the script: https://github.com/etactica/host_utilities/blob/feature/bluetooth_ota_python_bleak/bluetooth_ota_apploader_python_bleak/sl-ota-apploader.py

It happily scans and finds the device, then … fails to connect. This works fine on fedora desktop with bluez5.65, and it worked “back then” before I updated fedora as well.

Using bluetoothctl, I can see that I must leave scan on to get a connection to succeed? if I do “scan le” my device appears, but if I do “scan off” (to stop the console spam) and then “connect blah” it will fail. if I leave scan on, I can connect just fine