Limiting one Content item per Member in a Folder on Plone 4
Well, it is a sort of validation constraint, so maybe add a validator to the title field that in reality does not bother about the title, but checks the user etc.? (I think a field validator is passed enough information to pull this off, if not, overriding the post_validate method or listening to the corresponding event should work.)
If you try this, bear in mind that post_validate is already called while the user is editing (ie on moving focus out of a field).
I have created a custom Archetypes content type called "Résumé" and would like to enforce a limitation that lets a Member add only one item of this type inside a folder. Even better would be redirecting the member to the edit page of his or her item, if it already exists in that folder.
How can I enforce this limitation and provide this extra functionality?