Can't select OpenCloud as target for scheduled backups

[mtdcr]

For example, using AntennaPod, when opening a target folder for scheduled backups, Android (16, at least) does not offer OpenCloud as a target. The title of the chooser dialogue (hidden in the side menu) is "Öffnen aus" in German (open from).

However, when storing single files, OpenCloud does get offered. The title of the chooser is "Speichern unter" (save as).

DavX5 can be selected in both scenarios.

This can be easily reproduced with AntennaPod, which offers both manual and automatic backups in settings -> import/export. But I observed this in multiple apps.

[GZEI]

Hello,

maybe this issue is related to #24 and #69? Opencloud is sadly also not offered as a backup storage option in Aegis (a 2FA app for android).
I am not an android developer, so I am not sure how apps like seafile and nextcloud achieve this functionality, but my very short research suggests it could be related to an incomplete Storage Access Framework implementation.

Is there any update on this side?
Thank you for your great work :)

[DodoLeDev]

This app is offered in the Storage Access Framework (SAF) as a source for individual files and for exploration purposes, but is not available when choosing a target folder.

Examples :

• I want to attach a file to a mail: OpenCloud is available
• I want to explore OpenCloud through SAF's Files app: OpenCloud is available
• I want to save a file somewhere in my phone: OpenCloud is available
• I want to select a target folder in order to allow an app to automatically create backups: OpenCloud not available

Might be related to the supported actions flag the app assign to its files, or the methods that are effectively supported

Doc: https://developer.android.com/guide/topics/providers/create-document-provider#creating

[GZEI]

Any news on this?

[alvaroemtnez]

Same behaviour in GrapheneOS. Opencloud appears and works correctly as a storage provider in the native Files app, but not in other apps. It must be missing something in the SAF implementation, as in the native Files app it works incredibly well (even with airplane mode on, you can browse locally synced files perfectly). #99 seems related and on the right track (with my little knowledge about Android), and this would also solve #24, as if files can be picked from any app, there's really no need to sync local folders anymore or maintain two versions of the app like some people suggested.

In case it helps, RSAF (https://github.com/chenxiaolong/RSAF/blob/master/app/src/main/java/com/chiller3/rsaf/rclone/RcloneProvider.kt) does this brilliantly, even adding a switch to "pretend to be local storage", in case some app filters them (especially important for opencloud, as files made available offline, are actually offline...).

[alvaroemtnez]

Okay, so I ended up implementing it myself: https://github.com/alvaroemtnez/opencloud-android

I also added a toggle to pretend to be local storage (like RSAF does), in Settings > Advanced. So now you can select files from every app I tested (i did 2FAS, Tasks.org, Signal/Molly, Obsidian, Obtainium, etc.):

• Obsidian seems to be really picky and only accepts local storage. Hence the "pretend to be local storage" switch. At the moment there seems to be a bug on Obsidan's end, when you select external storage it gets in a loop with every app I tried it (even RSAF). But that's Obsidian's fault, not OpenCloud. At least now you can see the storage and select a folder.
• The rest of the apps with "normal" backup systems (i.e. a json or xml file), work like a charm instantly :)
• Apps like 2FAS that bring the native file picker to select a save location, work also flawlessy (as it's the file manager saving the file, not the app itself).
• Signal has been a complete disaster. The new backup system reads, writes and moves thousands of files concurrently. First backup works but the second one makes a mess with the tmp directories it creates and nukes the whole files directory. Push-only upload systems like Nextcloud's were a mess cos deleted files weren't synced to the remote, but opencloud's approach doesn't seem fit either. The most addequate one seems to be RSAF's: basically, "here's the webdav, do what you have to do".

For intensive (and inefficient) backup systems like Signal's with thousands of file operations I'd still recommend RSAF because it just bridges the file or operations to rclone and directly to the WebDAV endpoint, which is more simple and reliable than an upload queue in an Android app with limited resources. Tradeoff is, if there's no internet connection, it doesn't work, while OpenCloud's sync is specifically for that use case (keeps them in the upload queue, and when there's network, it uploads them). But the way Signal has implemented the new local backup system seems way out of scope to be considered for these kind of apps, they clearly decided to enforce local-only so you use their cloud backup. Former backup system would've worked (just the actual backup file, and the former one).

I used AI (Gemini 3.1 Pro) but the code generated is fairly easy to review (and so I did review). It's just adding the isChildDocument override function in DocumentsStorageProvider.kt, changing a couple things around in openDocument to make the UUID-based upload queue work, and then the UI changes for the "pretend to be local storage" toggle that just add that flag. And I obviously did the translations with AI, I don't know that many languages! :)

As soon as I do a bit more real-world testing, I'll prepare a PR (first time I do one and contribute to a project, sorry if i don't do it properly :/ i'll try my best). We'll see :)