One thing I noticed when working with nested resource routes in Rails is that it is technically possible for a user to visit a route where the child resource exists (and is therefore displayed correctly), but the id for the parent resource represents an object that is not actually related to the child resource. 

For example, in the route `users/:user_id/post/:id`, the user could type in a route where `:user_id` represents a user who did not make the post corresponding to `:id`.

What would be the best way to fix this so that if the user visits an invalid URL, the server redirects the user to the correct URL? 

I have already put some code in my controllers to handle this, but it's kind of awkward having to check the path in every controller action and then redirect the user to the appropriate url, especially since the URL helpers are different for every action. 

(`edit_user_post_path(@user, @post)`, `new_user_post_path(@user, @post)`) 

There has to be a better way, right?