How to add restrictions on who can delete a wiki page

Question

We are running an enterprise wiki site collection, now to improve contributions we have defined all users as Contributors to the wiki site, so they can add, edit, delete any wiki pages. And we have restricted certain people with the permission to approve. But we have run into a problem is that contributor users can (intentionally or by mistake) delete any wiki page, even if they are not the creator. So can I force this restriction on the wiki page deletion:-

1. Site collection admin & Approver users can delete any wiki page.

2. Contributor user can only delete a wiki page if he is the creator & its version number is 3 or less .version 3 means that the wiki page have been created but never modified by any user.

Can anyone advice on this please? Thanks

Answer 1

You can create a custom permission level that does not allow deleting. You'd essentially copy contribute and deselect the delete option. This solves point 1.

For point 2, there isn't really anything that handles this. Item level security settings on lists comes close, but it isn't fully what you need and isn't available in libraries. You'd probably need to roll an event receiver on item deleting and handle logic there.