Hide upload button with zero quota

[PVince81]

Whenever a user has zero quota, for example like guest app users, don't
display the upload button.

The quota value is retrieved for the attachment folder.

Fixes #4138

[SystemKeeper]

Shouldn’t this distinguish between upload and share? If a normal user is created without quota, he‘s not allowed to upload something, but he could still share something that was shared with him. This PR would hide both options..?

[PVince81]

Shouldn’t this distinguish between upload and share? If a normal user is created without quota, he‘s not allowed to upload something, but he could still share something that was shared with him. This PR would hide both options..?

I have tested this scenario as follows:

1. Admin shares a folder "pics" with guest user guest1 and allows everything, even reshares
2. Admin uploads a few pics into the "pics" directory
3. Admin starts a conversation and invites Guest1
4. Guest1 logs in and accesses the conversation
5. Guest1 selects "Share" from the attachment menu and pics one of the pictures out of the "pics" directory
   💥

The request fails with a 500 error that returns a page:

So it seems this is explicitly blocked by the backend.
If we want this as a feature, need to look into it separately and also examine potential side effects as I don't fully understand what else the backend is doing, like creating shares.

[SystemKeeper]

I've tested this yesterday with @Ivansss and it worked just fine. He shared a folder with me, I uploaded a picture and in talk shared in our conversation. So only difference was, that I uploaded the picture, but I don't see why it should behave differently there.

[PVince81]

I've tested this yesterday with @Ivansss and it worked just fine. He shared a folder with me, I uploaded a picture and in talk shared in our conversation. So only difference was, that I uploaded the picture, but I don't see why it should behave differently there.

@SystemKeeper were you logged in as a guest user from the "guests" app or as a regular user ?
Guest users from the "guests" app are blocked by the API.

[PVince81]

Alright, I think I see your point. You could be a regular user (not guest app user) but have zero quota.

Then the API would allow it.

This means we need another mechanism to detect if the current user is a guest app user.
So far I haven't found any in the frontend.

[SystemKeeper]

@PVince81 I'm a guest user on cloud.nextcloud.com (at least as far as I know)

[SystemKeeper]

Alright, I think I see your point. You could be a regular user (not guest app user) but have zero quota.

That was my main concern, yes!

[PVince81]

I need to retest everything (including changing attachment folder as guest) because I had an incomplete local setup. I had set the guest whitelist of apps to "files,spreed" and apparently it breaks shares.

[PVince81]

Okay, with the correct whitelist (default one + spreed) sharing from a received folder works fine.

I've adjusted the code to distinguish between "upload perm" and "share perm".