bug: iOS advertisment manufactuer data is not available when scanning while app is in background

[drolpi]

When I run a scan task while my app is in background the manufacturer data is not included in the advertisement data.

I am using capacitor v7 and iOS 18.3.

[peitschie]

Hi @drolpi

This sounds like a passive vs active scan difference: https://uynguyen.github.io/2020/08/23/Best-practice-Advanced-BLE-scanning-process-on-iOS/

If the advertisement data is important, you'll want to shift it from the scan response packet into the primary advertise packet 🙂

Unfortunately, there's nothing we can do from the plugin side.

[drolpi]

@peitschie what do you mean with "shift it from the scan response packet into the primary advertise packet"?

[drolpi]

On the peripheral side?

[peitschie]

@drolpi correct. This is a peripheral side change. This is the difference between the advertising packet (ADV_IND) and the scan response packet (SCAN_RSP): https://stackoverflow.com/questions/75292547/are-ble-devices-required-to-respond-to-a-scan-req-requests

The fact this only shows up when the application is in the foreground means the peripheral only provides the data in the scan response. If it's critical to receive this data in the background, the only solution is for the peripheral to instead send the data in the advertising packet itself.

[peitschie]

You can see the distinction more clearly using something like nrf Connect (Android, but they may have an iPhone equivalent)