Ok the content is harvested even if not published inside OJS, but bibliographic databases fetch url that are then presented to their users. Which url is presented if the original content has not been published?
To give you the context of my question my aim would be to build a journal, using a CMS different from OJS, may be with a good JSON Api (e.g. wordpress), that could be able to use the great functions that have been developed inside OJS, to connect to DOAJ, CrossRef, etc.
I've read the page in OJS wiki on the integration between Wordpress and OJS and I've got the feeling that there is a lot of code to rewrite (for example the OJS rest plugin doesn't work, etc.)