Wait notification functionality feature

[vovagorodok]

Will be nice to have functionality like client.wait_for_notify() in order to have possibility to write simple scripts of serial communication that works like:

await client.wait_for_notify()
await client.read_gatt_char(tx_char)

I have this issue in my ArduinoBleOTA library for firmware uploading over ble:
https://github.com/vovagorodok/ArduinoBleOTA/blob/7fb9e079cf54e02b0701d117754e14ebe5db34cf/tools/uploader.py#L144

[dlech]

As a workaround, you could use an asyncio.Event(). The notification callback would need to call event.set(), then you would do:

await event.wait()
await client.read_gatt_char(tx_char)
event.clear()

[vovagorodok]

As I see callback has bytearray as second argument. It means that value from characteristics is being read during callback and await client.read_gatt_char(tx_char) will read from characteristics second time?

[dlech]

Based on your example, I thought that maybe you had a case where the value was too large to fit in a notification and you had to do a read to get the full value. But if you just want to use the value from the notification and not read again, then you can use asyncio.Queue() instead of asyncio.Event() and leave out the read.

[vovagorodok]

Thanks! I will use asyncio.Queue() as solution. There are any plans to add method like client.wait_for_notify() or solution with asyncio.Queue() looks ok from Your PoV?

[dlech]

No concrete plans. But having something that could be used in an async for loop like we did for advertisement data in #1361 could be nice.

[vovagorodok]

Should we close this issue or hold in order to track progress?

[dlech]

I don't see any duplicate issues, so let's leave this one open.