The Forms folder structure is not sanitized which can lead to synchronization issues when uploading files

[stefan0xC]

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Describe the bug
Uploaded files are seemingly saved in a folder structure Forms/{id of form} - {title of form}/{id of submission}/{id of question} - {title of question} but the titles do not seem to get trimmed in regards to trailing white spaces, which results in syncing problems (at least on Windows 11 with NTFS).

To Reproduce
Steps to reproduce the behavior:

1. Go to Forms and create a new form
2. Call it test with a trailing whitespace
3. Add a file upload option and call it test as well
4. Upload a file

Expected behavior
I expect the fields that are used for filenames to be trimmed in regard to whitespace and maybe also sanitized regarding other invalid characters like :

Screenshots
If applicable, add screenshots to help explain your problem.

Nextcloud (please complete the following information):

• Nextcloud-Version: 30.0.2
• Forms-Version: 4.3.3

Desktop (please complete the following information):

• OS: Windows 11 with NTFS file system
• Nexcloud Desktop v3.14.3

[Chartman123]

@Koc one more bug related to the file question type. I also had a similar issue with a : in the question title. So we should remove all offending characters from the folder names.

[Koc]

I've tested it few scenarios:

1. create form with trailing :
2. create file question with trailing :
3. upload file on Linux (devcontainer)

everything works fine

1. create form with trailing :
2. create file question with trailing :
3. upload file on Linux (devcontainer)

the same

We're already using normalizeFileName which uses \OCP\Constants::FILENAME_INVALID_CHARS under the hood. And as far I can see from the constant description - we aren't supporting Windows.

[Chartman123]

@Koc yes that's right, at least server side. But the official sync client sure does support Windows. Perhaps we can have a look how Server/Files solves that problem?