Scanning and connecting to a device without SCAN_RESP packet?

[zapta]

• bleak version: 0.19.5
• Python version: Python 3.10.7
• Operating System: Windows 10
• BlueZ version (bluetoothctl -v) in case of Linux:

Description

I have a BLE device which sends adv packets but for some reason doesn't send scan response packets and am resolving it with the vendor espressif/esp-idf#10660 . My question here is regarding Bleak.

If I use the Nordic nRF Connect app on my phone, I see the device in the scan list and can connect to it with no problem even though the device didn't respond to SCAN_REQ (verified with wireshark). However, when I use a python program with Bleak, it doesn't show in the Bleak scan list and if I try to connect directly by specifying the address it Bleak still doesn't connect.

Is there a way to tell Bleak to not require a SCAN_RESP packet and list and connect to the device regardless?

What I Did

I ran a python script with a bleak scanner and captured the traffic with wireshark and a Nordic dongle. The computer with the Bleak scanner did sends a SCAN_REQ, but didn't get back a SCAN_RESP and ignored the device. The wireshark packet file and screen shot are included below.

Logs

C:\projects\esp32\repo\release\windows>set BLEAK_LOGGING=1

C:\projects\esp32\repo\release\windows>analyzer.exe --scan
OS: Windows-10-10.0.19044-SP0
Platform:: uname_result(system='Windows', node='Ryzen', release='10', version='10.0.19044', machine='AMD64')
Python 3.10.7 (tags/v3.10.7:6cc6b13, Sep 5 2022, 14:08:36) [MSC v.1933 64 bit (AMD64)]
Scanning 5 secs for advertising BLE devices ...

2023-01-30 19:33:32,751 bleak.backends.winrt.scanner DEBUG: Received 30:E2:83:7C:F3:11: .
2023-01-30 19:33:32,752 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:32,752 bleak.backends.winrt.scanner DEBUG: Received 3A:35:F1:22:AE:BD: .
2023-01-30 19:33:32,849 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:32,849 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:32,983 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:32,984 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:33,568 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:33,569 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:33,797 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:33,797 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:33,799 bleak.backends.winrt.scanner DEBUG: Received 3A:35:F1:22:AE:BD: .
2023-01-30 19:33:34,394 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:34,395 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:34,516 bleak.backends.winrt.scanner DEBUG: Received 3A:35:F1:22:AE:BD: .
2023-01-30 19:33:34,624 bleak.backends.winrt.scanner DEBUG: Received 3A:35:F1:22:AE:BD: .
2023-01-30 19:33:34,887 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:34,887 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:34,984 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:34,985 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:35,568 bleak.backends.winrt.scanner DEBUG: Received 3A:35:F1:22:AE:BD: .
2023-01-30 19:33:35,573 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:35,573 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:36,162 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:36,163 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:36,514 bleak.backends.winrt.scanner DEBUG: Received 3A:35:F1:22:AE:BD: .
2023-01-30 19:33:36,527 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:36,527 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:36,750 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:36,751 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:37,111 bleak.backends.winrt.scanner DEBUG: Received 24:D7:EB:15:27:8E: ESP_GATTS_DEMO.
2023-01-30 19:33:37,112 bleak.backends.winrt.scanner DEBUG: skipping callback, waiting for scan response
2023-01-30 19:33:37,317 bleak.backends.winrt.scanner DEBUG: 1 devices found. Watcher status: 3.
1 device address: 3A:35:F1:22:AE:BD ()

Scanning done.

C:\projects\esp32\repo\release\windows>

Attachments

bleak_scan.zip

[zapta]

... Not an expert but it seems that bleak ignores devices that have adv data only. Could be added to the device list at the end of the scanning period (?).

https://github.com/hbldh/bleak/blob/develop/bleak/backends/winrt/scanner.py#L139