OK, maybe maybe I didn't express myself correctly =)
I would like to select a storage medium via the dashboard. So that you can save the created pdf in the desired location.
I would actually like to be able to guarantee that the path is correct when I exchange the storage medium.
the node-red-contrib-fs-ops node can probably be used here to dir list and there is another fs-ops node that can check access etc. After that you will need to build/populate dashboard elements that present the options.
PS, is node-red installed in the same place you insert the USB? Or a different computer?