Storage Access Framework support

[gilbsgilbs]

Hi,

I thought it would be useful should this app implemented the Storage Access Framework interface so that third-party apps could read/write files directly from/to the remotes through rclone.

Do you think it would be feasible? I could give it a try sometimes.

[x0b]

Development for Storage Access Framework (SAF) support has been going on for over a year now, but has been slow because you need to bridge the java/kotlin environment of Android into the go environment for rclone. And both the design and implementation of SAF in Android have numerous flaws.

Anyway, I've spent a bit more time over summer on this issue. Part I of the SAF integration is close to ready and is planned for preview release in September. This will include a SAF client and a translation layer between SAF <==> rclone. With this, rclone can address SAF storage locations just like any other remote.

Part II however, a SAF DocumentsProvider, is still in a very early development phase. This is what's required to allow third party apps to access rclone remotes using Android SAF APIs.

Meta operations (list/delete/move/rename) are relatively easy to implement. Most problems currently revolve around retrieving and storing actual file bytes efficiently. And with my next semester starting soon, development effort will focus on maintenance rather than feature development.

You can see the current state in the wiki: RcloneExplorer 1.9 feature preview

[gilbsgilbs]

Great @x0b, thanks. If you need any help, please let me know.

Edit: crap, I did not realize Android 10 drops support for file access through Linux API. This is so bad. Thanks Google I guess 😒.

[x0b]

If you need any help, please let me know.

I appreciate the offer and may come back to it :).

Edit: crap, I did not realize Android 10 drops support for file access through Linux API. This is so bad. Thanks Google I guess 😒.

So technically this is not true - you can still use the Linux API to access your app-specific directories. You just can't use the API for anything outside of these locations, i.e. the API is useless to access user-visible storage.

For Android 10 at least, we can opt-out - but:

Warning: Apps will be required to use scoped storage in next year's major platform release for all apps, independent of target SDK level.

...meaning that on Android 10.1/Android 11, SAF integration needs to be ready regardless of Target SDK, so this is the hard deadline.

[x0b]

I'll reopen this since part II is not yet released.

Part I, the SAF client, has been released since 1.9.0 and can be used as described in the documentation

Update 2019-11-03: I've fixed a few major bugs with the VirtualContentProvider and it is slowly progressing towards a usable state. There's still a security review and clean-up to do, so it will probably take a bit of time until the next major feature update.