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Re: Should we expose all devices as if they were bonded?

From: Rob Moran <Rob.Moran@arm.com>
Date: Thu, 17 Mar 2016 11:06:36 +0000
To: "Christiansen, Kenneth R" <kenneth.r.christiansen@intel.com>, "Jeffrey Yasskin" <jyasskin@google.com>, public-web-bluetooth <public-web-bluetooth@w3.org>
Message-ID: <AM2PR08MB0180E8880135ED67819E03E2E58B0@AM2PR08MB0180.eurprd08.prod.outlook.com>

IMO having the device appear unbonded and requiring a user to re-discover services and re-register for events, etc. after a disconnect is a cleaner and more atomic approach.
Requiring the user to register for service changed events and possibly holding stale services (as they may not exist after a reconnect) could create more edge cases and potential errors to cover.

In this scenario, I think the item to persist between connections is the security context, so that any further reconnections don't require a user action to undertake, but still honour the original service / name filters.

Cheers,

Rob
________________________________________
From: Christiansen, Kenneth R <kenneth.r.christiansen@intel.com>
Sent: 17 March 2016 10:39
To: Jeffrey Yasskin; public-web-bluetooth
Subject: RE: Should we expose all devices as if they were bonded?

At least for development purposes it would be nice to have them unbounded (but I guess we could have a way to change the behavior in devtools when it is open)

I am not sure whether I want the notifications to be queued, at least not by default. Think about something like temperature change and heart rate measurements.

Kenneth

> -----Original Message-----
> From: Jeffrey Yasskin [mailto:jyasskin@google.com]
> Sent: Thursday, March 17, 2016 2:22 AM
> To: public-web-bluetooth <public-web-bluetooth@w3.org>
> Subject: Should we expose all devices as if they were bonded?
>
> Two issues came up recently where the Bluetooth spec defines different
> behavior depending on whether a device is bonded.
>
> In https://groups.google.com/a/chromium.org/d/topic/web-
> bluetooth/PQpZAFNlvT4/discussion
> and https://github.com/thegecko/web-bluetooth-dfu/issues/12, Luiz is
> suggesting that we have Web Bluetooth remember services, characteristics,
> and descriptors across disconnection, even when there's no physical bond.
> That's similar to treating the web site as bonded to the peripheral. We'd in
> the case of no bond, we'd re-discover the known services, etc. after re-
> connecting, and send service-changed events for the ones that have
> changed. We'd also allow users to hold onto Service, etc. objects across
> disconnect/connect pairs, and continue using the objects afterward. On the
> other hand, if we treat pages as un-bonded, users would need to re-fetch
> services, etc. before using them after a disconnect/reconnect pair.
>
> In https://github.com/WebBluetoothCG/web-bluetooth/issues/220 and
> https://bugs.chromium.org/p/chromium/issues/detail?id=589796, we have
> to decide whether users need to re-subscribe to notifications after a
> disconnection. If we treat pages as bonded, the notification state should
> persist across disconnections. If we treat pages as non-bonded, the state
> should reset to unsubscribed on disconnection. (3.G.3.3.3.3) If we keep the
> page subscribed across disconnection, users might expect us to queue
> notifications, or at least indications, and deliver them the next time the page
> is connected. Should we do the same if the page is unloaded? That kind of
> unbounded queueing seems problematic.
>
> And, of course, beyond always treating a page as bonded or not-bonded, we
> could make the page's bonded-ness depend on the presence of a physical
> bond.
>
> Are there other areas where treating the page as having or not-having a
> bond would cause divergent behavior?
>
> Which behavior do you folks think makes more sense for the web API?
>
> Jeffrey

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Received on Thursday, 17 March 2016 11:07:04 UTC

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