Actually done some WebDAV, did a small client (talking to Apache) from JS that worked well enough for my purposes.

The nasty surprise was doing the server-side (for a hobby-project), many layers. Luckily found out that something called DavTest exists (it's included with Debian) so testing most basic things wasn't too bad.

Then tried mounting from Windows and running into a bunch of small issues (iirc you need to support locking), got it to mount before noticing notes about a 50mb file-size limit by default (raisable.. but yeah).

It's a shame it's all such a fragmented hodge-podge because adding SMB (the only other "universal" protocol) to an application server is just way too much complexity.