[Psi-devel] Re: Re: Delivery confirmations

[Yves Goergen]

On 16.03.2005 22:21 (+0100), Trejkaz wrote:
> There is also a third possibility: the user got the message, they do support 
> the feature, but the confirmation message failed to get back to the sender.

> LOL.  But on a serious note, how do you know which client they had online at 
> the time the message was received?  Even if it were done using proper caps, 
> if you're not online at the time they receive their message, you don't know 
> their capabilities as you weren't there to see them.  The way I see it, this 
> sort of feature is almost exclusively for offline messages, as when the user 
> is online, they can respond to the message directly, and you know they 
> received it based on their response.

I'd say this is semi-determinable. You can only know for sure the
message was delivered, read, deleted or whatever the signal is about,
but you can't say it wasn't due to its missing. One-way proof.

* The network could have eaten up the message itself.
But also:
* The other client could not support this system.
* The other client could be teached to not support this system.
* The other client could be teached to not acknowledge anything.
* The network could have eaten up the reply.
* The recipient could wait an arbitrary time to take an action.
Did I forget something?

So on the UI side, there's a green checkmark if delivery has been
acknowledged and there's no checkmark otherwise. This is exactly the
same with e-mail today, be it TB's read ack message or Exchange's
delivery report. And I can't imagine public compatibility allows
anything else.

-- 
Yves Goergen "LonelyPixel" <nospam.list at unclassified.de>

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