Error on additional parameters?

[timjnh]

Are there any options to trigger error responses if extra parameters are provided? I'd like to get errors by default if a caller provides fields beyond my specification. I understand that I can strip them with declared but I want to tell people when they're calling my API incorrectly and I'd prefer not to have to write boilerplate to compare params and declared(params) for every route.

To be clear, I'm looking for this configuration:

params do
  requires :user, type: Hash do
    requires :name, type: String
  end
end

to return a 400 if I provide the following JSON:

{ "user": { "name": "me", "other_field": "bleh" } }

[dblock]

This is a dup of #810, so I am going to close it, but this is a great feature! Would love to see someone contribute a solution for it. There are some ideas in that issue about how this could be implemented.