support chunked uploads

[butonic]

from https://github.com/owncloud/ios/issues/187#issuecomment-222617620

The iOS app does not take advantage of the file chunking as the desktop or the Android app does. The reason why we decided to drop this was because we'd rather the background support (keep transfers alive althought the app is closed for more than 3 min); we had to decide either support chunks or background and we though that it was better the second one so that we avoid having to have the app open for the transfer to happen.

why not make chunks small enough to fit inside the 3min background window? how does dropbox handle this?

00006472

cc @davivel @PhilippSchaffrath

[rperezb]

@butonic dropbox cancel the transfers if the app is not in the foreground This is not only for uploads but also for downloads (imagine a folder download)

[butonic]

@rperezb do they resume or start over?

[butonic]

@davivel this is the ios issue regarding uploads on iOS

[butonic]

@davivel maybe it is easier to send heartbeat requests in parralel so the session does not timeout.

[butonic]

@davivel ping mo to create a test account at the customer.

[davivel]

@butonic, we don't use heartbeat in mobile clients.

How long is the session timeout?

[phisch]

@davivel: the session lifetime is 24 hours by default but it is configurable and might be 1 hour or a few minutes. Depends on the owncloud admins security guidelines.