Can an app reliably upload data when it is backgrounded?

Question

The docs don't seem to offer any guarantees - I'm just wondering if anyone's had any experience of uploading a large amount data after a user 'backgrounds' an iPhone app.

Eg, recording some audio or video and uploading it while there's the possibility that the user will start another app. Is is reasonable to expect to be able to be able to upload several MB of data in the background, perhaps using the VOPI UIBackgroundMode, which should keep sockets active?

Answer 1

First, uploading anything that is not VoIP data in a VoIP background mode violates Apple's guidelines and will probably get your app rejected. But you still have the option of using the normal background task completion API that gives your app another 10 minutes (at the moment, the amount might change in a future release) to finish a task like an upload.

If a foreground app uses a large amount of bandwidth, it is likely that the OS will give it priority over the background task.

Of course, you cannot rely on your upload being finished. If you run out of time, the system will notify you and you should try to resume the upload when the user reactivates your app. But you can't rely on a stable internet connection anyway, even if your app is in the foreground, so I don't really see the difference.

Answer 2

NO, this is not possible. i agree that it creates problems when you have a long operation to make but it is defiantly not possible.