Unavailable External Storage (server-side) prevents Nextcloud App from working (maintenance mode)

[ytausch]

Steps to reproduce

1. Add a external WebDAV storage that is unavailable in a normal user account
2. Login with a newly installed Nextcloud App

Expected behaviour

• Everything should work normally - when opening the unavailable storage, a helpful message should appear

Actual behaviour

• No folder sync happens - instead the app displays a "maintenance mode" message.

Can you reproduce this problem on https://try.nextcloud.com?

• Not possible as I cannot add external storage there.

Environment data

Android version: 8.0.0

Device model: Samsung SM-A520F

Stock or customized system: Stock

Nextcloud app version: latest from Google Play (3.11.1)

Nextcloud server version: 18.0.3

Reverse proxy: nginx-proxy (Docker)

[tobiasKaminsky]

@nextcloud/server-triage without having this checked, but as Android "only" displays the list we get from server, might this be a problem on server side?

@ytausch how does web behave?

[ytausch]

Web works fine. It displays an error message when opening the unavailable external storage folder.

[MorrisJobke]

@nextcloud/server-triage without having this checked, but as Android "only" displays the list we get from server, might this be a problem on server side?

@tobiasKaminsky Maybe try to create a external storage, mount it to root and then make it unavailable in the external storage itself (stop ftp/sftp for example). Check then if the Android app supports this.

[tobiasKaminsky]

I did this:

• created an external mount on my server1 to server2
• disabled server2
• webdav request shows:

<d:response>
    <d:href>/nc/remote.php/webdav/Nextcloud/</d:href>
    <d:propstat>
      <d:prop>
        <d:resourcetype>
          <d:collection/>
        </d:resourcetype>
        <oc:favorite>0</oc:favorite>
        <nc:is-encrypted>0</nc:is-encrypted>
        <nc:mount-type>external</nc:mount-type>
        <oc:id>-0000001ocjycgrudn78</oc:id>
        <d:getetag>&quot;&quot;</d:getetag>
        <oc:permissions>MG</oc:permissions>
        <oc:share-types/>
        <oc:owner-id>tobi</oc:owner-id>
        <d:quota-used-bytes>0</d:quota-used-bytes>
        <nc:sharees/>
      </d:prop>
      <d:status>HTTP/1.1 200 OK</d:status>
    </d:propstat>

Question: how does web UI knows that it not available (entry marked red)
Then I can prevent entering this folder.

Accessing it gives:

<?xml version="1.0" encoding="utf-8"?>
<d:error
  xmlns:d="DAV:"
  xmlns:s="http://sabredav.org/ns">
  <s:exception>Sabre\DAV\Exception\ServiceUnavailable</s:exception>
  <s:message>Storage is temporarily not available</s:message>
</d:error>

--> I will parse this response and show it as error message.

[MorrisJobke]

So there are two ways:

• either you call /status.php to check for the maintenance mode - there shouldn't be too often a 503 anyways and status.php is quite cheap
• another option would be that we add another HTTP header that indicates if the system is in maintenance mode

[tobiasKaminsky]

I would like to go with option 2 as this is just a more cleaner behaviour, and also other clients can more easily adopt this.