Is there a way to share a file/folder to another owncloud user directly from the desktop client ? I know it's possible from the web UI, but from any desktop app (tested windows and macOS), i only have the public link sharing available.
Is it totally impossible ? Have I missed something ?
When you right-click you have an option "share with ownCloud" there you can create both a public link as well as share with any user or group in your ownCloud!
Hey @plesyx, as @hodyroff points out, there's two main sections on the "Share with ownCloud" dialog: the one you mentioned on your first comment and one for users. Check this out for an explanation on how to share with users/groups inside or outside (federated shares) your ownCloud:
Note that, for the federated share you just need to use the qualified name of the user: <username>@<server_URL> in the searchbox.