class Doorkeeper::TokensController

def introspect
  introspection = OAuth::TokenIntrospection.new(server, token)
  if introspection.authorized?
    render json: introspection.to_json, status: 200
  else
    error = introspection.error_response
    headers.merge!(error.headers)
    render json: error.body, status: error.status
  end
end