Rails - solution for records-level acl

I find many plugins which implements access control under controller-methods level, but i have some special situation:

for example, we have PostsController#index

def index
  @posts = Posts.all
end

i want to get records with scope -> where(:user_id => current_user.id). This is simple, but i want to do this on acl-level. Of course scopes and conditions can be much more complex, like -> 'retri开发者_如何学Cve only posts posted in specific country' etc.

The simplest approach would be to solve that via associations and not additional plugins.

 current_user.posts.all

 country = Country.find(...)
 country.posts.all

 ...

A perfect balance of readability, performance, and flexibility.