disconnect() behaviour mismatch WinRT/bluezdbus

[patman15]

Hi!

To avoid stale connections, I thought (and I think I have seen an example like this) that it is a good idea to always call disconnect() on a BleakClient to avoid stale connection before connecting again. I did so in my code
https://github.com/patman15/aiobmsble/blob/7c0ea3e3220745a3d98ef10c532602fee2726099/aiobmsble/basebms.py#L331-L343

I didn't find any hints in the user manual whether this is allowed or not, so I checked the bluezdbus implementation which is safe. Unfortunately, I now found out that the WinRT implementation has an assert that raises in case the client is not connected.

Thus, my question(s): should the behavior be identical, if so, which way? If not, should it be documented, that the application needs to check the connection state? (Honestly, I considered the way that I always can call disconnect() very handy!)

Thanks,
Patrick

[dlech]

Bleak works best if you create a new BleakClient object each time you want to connect instead of reusing the same one. The current situation with the state of the object after disconnect is kind of a mess and isn't easy to fix, which is why creating a new object is recommended.

[patman15]

Ok, I was a bit imprecise. I do not try to reconnect the "old" client, I just try to disconnect the old instance (which may or may not be connected) before I leave it to the garbage collection and generate a new instance with which I connect. In essence something like:

for i in range(5):
  myclient = BleakClient()
  if in_the_mood:
     myclient.connect()
     myclient.start_notify()
  myclient.disconnect()
  sleep(1)

Of course my code is more complex, see previous link, but in essence it is this and works well on Linux. The main question is "can I call disconnect if I'm not sure the BleakClient is connected" which seems to be answered with yes on Linux but no on Windows.

[dlech]

If you never connected the instance, then there is no need to call disconnect(). Also, we have an async context manager so that you don't have to worry about disconnect at all.

for i in range(5):
  myclient = BleakClient()

  if in_the_mood:
     async with my_client:
         myclient.start_notify()
         # needs some waiting here to avoid immediate disconnect
  sleep(1)

It probably makes sense to allow calling disconnect() even when not connected though.

[patman15]

Also, we have an async context manager so that you don't have to worry about disconnect at all.

I know, but unfortunately, that doesn't work in my case.

It probably makes sense to allow calling disconnect() even when not connected though.

Well, that was my point (or that it needs to be documented that you shall not call disconnect() when not connected). Do you want me to prepare a PR for the code change (or the documentation)?