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Comment by jeffbr13 | Hacker News Reader

So, the problem is that the app itself can't run (reliably) in the background to respond to key-exchange requests?

It looks like iOS apps aren't allowed network connections when in the background[0]. So would another platform with fewer restrictions on background processes (e.g. Android?) be able to perform key-exchange while the app is backgrounded?

(forgot the link:)

[0]: https://developer.apple.com/library/ios/documentation/iPhone...

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Not really...you'd still need to be online which isn't always the case.

But surely you must have enough connectivity for a key-exchange to take place (most of the time) if you're able to receive push notifications in the first place?

iOS push notifications are about one idea: power management. By forcing all servers to communicate to their apps through one channel, the actual iOS hardware only needs to maintain one connection: the connection to Apple's servers.

The alternative is that 3, or 8, or dozens of apps all maintain separate connections to their own motherships, which drains a device's battery like a mynock with a case of the munchies.

i guess there could be a system service where you register "please check server x for new messages every y minutes" and the service would handle the queue intelligently to save power?

In real life, apps just leak your passwords into the cloud and send you push notifications. Thats how the average jabber IM on an iphone stays online when the app is in the background.

One of these apps tried to connect to my jabber server even after I deleted it from the phone.

Actually you can have time limited connections with VoIP socket background processing mode. IOS 7 also has some new push features that cover one corner case that VoIP sockets didn't cover.

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