Thanks Kovid,
I already found that.
Problem is I am (still) unable to find out what I should use.
Problem at hand is I want to programmatically control a Calibre lib which reside on my NAS (I'm using
https://hub.docker.com/r/aptalca/docker-rdp-calibre/, if that matters) accessible only through web.
What I need is essentially to be able to insert an empty book to the lib and, later, to modify metadata and/or content.
The srv/ajax.py module has means to query but apparently not to POST a new book.
srv/cdb.py may be what I need, but it's usage isn't obvious.
Can You provide a bit more insight?
TiA