Webdav external storage wrong type when deleted files app is enabled

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1

Hello,

Iā€™m developing a custom app for my Nextcloud instance that adds a new external storage backend option based on WebDAV, with some additional features. The integration works perfectly when connecting external storage using this new type. However, Iā€™m encountering issues when trying to perform WebDAV operations like creating a folder. Specifically, the process fails under certain conditions.

Workflow Overview:

  1. When a user registers via the Registration app, a hook is triggered.
  2. This hook iterates through all external storages of the custom type.
  3. If the backend type is WebDAV, a request is sent to create a specific folder.

The Issue:

Sometimes, instead of the expected storage type \OC\Files\Storage\DAV, the type is OCA\Files_Trashbin\Storage. Below is the relevant code snippet:

foreach ($externalStorages as $externalStorage) {
    if ($externalStorage->getBackend()->getIdentifier() != "customType") {
        continue;
    }

    if (!$externalStorage->getBackendOption('auto_create_folder')) {
        continue;
    }

    $mountPointInstance = $this->mountManager->find($externalStorage->getMountPoint());
    $storageClass = $externalStorage->getBackend()->getStorageClass();

    // Resolve the remote subfolder if it contains $user
    $storageArguments = $externalStorage->getBackendOptions();
    $resolvedMountpoint = str_replace('$user', $event->getUser()->getUID(), $externalStorage->getBackendOption('root'));
    $storageArguments['root'] = $resolvedMountpoint;

    // Get storage instance of type DAV to use mkdir and other functions
    $storage = $this->storageFactory->getInstance($mountPointInstance, $storageClass, $storageArguments);

    if ($storage instanceof DAV) {
        // Create folder
    }
}

When the type unexpectedly changes, disabling the ā€œDeleted filesā€ app resolves the issue, and everything functions correctly. However, re-enabling the app causes the failure to return.

Question:

Why would enabling the ā€œDeleted filesā€ app impact the storage type in this way? Is there something within my custom app or the Nextcloud environment that might be causing this interaction? Iā€™m uncertain whether the problem lies within my app, but without the proper type check, the WebDAV operations will fail.

Any insights would be greatly appreciated!

Thank you.

2

Hi Florian,

additional logic, like the trash bin, is implemented as storage wrapper around the actual storage.

Each storage implements the IStorage interface.

I think you are looking for server/lib/public/Files/Storage/IStorage.php at 3973a8f722c4acf5da82a611ee50f04e19627727 Ā· nextcloud/server Ā· GitHub.

1 Like
3

@kesselb do you mean, I need to replace the condition by using the instanceOfStorage function can fix this behavior ?

4

Yep, instanceOfStorage will look through the storage wrappers and tell you if the source storage is of the given type.

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