Cloud storage where others can add/modify but not delete?

Question

I have a large collection of files to share for everyone, and I'm looking for a cloud service that matches all or some of these needs (sorted by importance):

• Allow others to upload, download files, create folders and move files between folders, but restrict them from delete files
• Be recoverable if something goes wrong (revert deletions)
• Visitors can view without downloading (mostly PDF)
• Have stat, or can integrate with Google Analytics
• Free for a couple GB (at least 3 GB)
• Visitors can have a synced copy in their hard drive

So far I'm using Google Drive, but the edit mode allow others to delete the files as well.

Answer 1

Nextcloud is an open-source alternative to google drive. The software is free but it is self-hosted. Registered users can also sync documents shared with them.

✔️ Allow visitors to upload, download files, create folders and move files between folders, but restrict them from delete files
✔️ Be recoverable if something goes wrong
✔️ Visitors can view without downloading
❌ Have stat, or can integrate with Google Analytics
✔️ Free for a couple GB: you can choose free providers listed on their website, or your own host by your wish
✔️ Visitors can have a synced copy in their hard drive

Answer 2

One limited option is to keep using Google Drive, set the whole folder as "can view" privilege, and create a folder in "can edit" privilege.

Many good discussion and other options can be found here: Cloud services that can open for everyone to edit, but not delete files : opendirectories