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Bluetooth support for the Web.
http://www.w3.org/community/web-bluetooth/
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How to invalidate characteristics cache given that Service Changed is not implemented yet? #592

Open zachmoshe opened 1 year ago

zachmoshe commented 1 year ago

I look for the supported way to cause Chrome (or any browser) to invalidate the services and characteristic cache it holds on my device (still under development so I play with the services quite frequently). As far as I understand, the Service Changed characteristic is the bluetooth way to go, but it seems (here) that it's not implemented yet in any of the browsers.

Is there any other supported (and implemented) API to make the browser rediscover services? If not - is there any cache folder that I can delete? (I assume that would be browser specific, I'm referring to Chrome here, but I guess any answer will be useful for some of the future readers)

dlech commented 1 year ago

The browser doesn't cache the services, it is all done in the OS Bluetooth stack, so clearing the cache is OS-specific.

If the services don't actually change at runtime, I would suggest using the Database Hash characteristic (0x2B2A) instead of Services Changed characteristic or using a random Bluetooth address so that the OS cache is avoided altogether.

zachmoshe commented 1 year ago

Thanks! I wasn't aware of that.
IIUC I can just set a random value for the Database Hash Characteristic every time, right?