Collabora not loading when trying to open document from not logged in user

[borjaevo]

Describe the bug Im trying to use VDR functionlity. I set up collabora online to display watermarks for some tagged files and user groups. When trying to share a folder with a public share link (so its the only option where i can hide download button) and the anonymous user try to open the files, collabora online starts loading but only loads the header and a grey content screen. No errors displayed.

To Reproduce Steps to reproduce the behavior:

1. Go to the folder that contains the documents you want to share
2. Click on share link
3. Enable hide downloads button
4. Open the link in a private window in some browser
5. Try to open the file

Expected behavior Collabora opens the file with the watermarking

Screenshots

Client details:

• OS: [e.g. iOS] PopOS
• Browser [e.g. chrome, safari] Firefox 90
• Version [e.g. 22] 22
• Device: Multiple browsers and devices tested

Server details

Operating system: Debian 10

Web server: Apache

Database: MariaDB

PHP version: 7.4

Nextcloud version: 22

Version of the richdocuments app 6.4.1004

Version of Collabora Online 4.2.1

Logs

Nextcloud log (data/nextcloud.log)

Exception: Argument 1 passed to OC\Group\Manager::getUserIdGroupIds() must be of the type string, null given, called in /home/cloud.xxxx.com/public_html/lib/private/Group/Manager.php on line 316

Browser log

Uncaught TypeError: docLayer is undefined
    _handleKeyEvent https://cloud.biobide.com/apps/richdocumentscode/proxy.php?req=/loleaflet/2afbc52/bundle.js:1
    _onKeyDown https://cloud.biobide.com/apps/richdocumentscode/proxy.php?req=/loleaflet/2afbc52/bundle.js:1
    handler https://cloud.biobide.com/apps/richdocumentscode/proxy.php?req=/loleaflet/2afbc52/bundle.js:1
proxy.php:1:1786242
Uncaught TypeError: docLayer is undefined
    _handleKeyEvent https://cloud.biobide.com/apps/richdocumentscode/proxy.php?req=/loleaflet/2afbc52/bundle.js:1
    _onKeyDown https://cloud.biobide.com/apps/richdocumentscode/proxy.php?req=/loleaflet/2afbc52/bundle.js:1
    handler https://cloud.biobide.com/apps/richdocumentscode/proxy.php?req=/loleaflet/2afbc52/bundle.js:1




</details>

[juliusknorr]

Looks similar to https://github.com/nextcloud/deck/issues/3247

Could you share the full error message from the nextcloud.log file as that would give a better hint on where exactly the error occurs.

[juliusknorr]

From the forum trace it looks like it could be related to watermarking https://help.nextcloud.com/t/nextcloud-office-bug-document-fails-to-load-on-share/135192

Caused by TypeError: OC\Group\Manager::getUserIdGroupIds(): Argument #1 ($uid) must be of type string, null given, called in /var/www/nextcloud/lib/private/Group/Manager.php on line 316
    /var/www/nextcloud/lib/private/Group/Manager.php - line 316:
    OC\Group\Manager->getUserIdGroupIds()
    /var/www/nextcloud/apps/richdocuments/lib/Controller/WopiController.php - line 334:
    OC\Group\Manager->isInGroup()
    /var/www/nextcloud/apps/richdocuments/lib/Controller/WopiController.php - line 223:
    OCA\Richdocuments\Controller\WopiController->shouldWatermark()
    /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 217:
    OCA\Richdocuments\Controller\WopiController->checkFileInfo()
    /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 126:
    OC\AppFramework\Http\Dispatcher->executeController()
    /var/www/nextcloud/lib/private/AppFramework/App.php - line 157:
    OC\AppFramework\Http\Dispatcher->dispatch()
    /var/www/nextcloud/lib/private/Route/Router.php - line 302:
    OC\AppFramework\App::main()
    /var/www/nextcloud/lib/base.php - line 1006:
    OC\Route\Router->match()
    /var/www/nextcloud/index.php - line 36:
    OC::handleRequest()

[juliusknorr]

The relevant code part has been moved and now has a proper null check already at

https://github.com/nextcloud-releases/richdocuments/blob/2056dfdb6971cad28d9c0eaf85cca7cfc36ee0b4/lib/PermissionManager.php#L175-L178