module RouteSpy
  def matches?(request)
    if response = super(request)
      File.open(Rails.root.join('tmp', 'default_route.txt').to_s, 'a') do |file|
        file.write(request.inspect)
      end
      response
    else
      false
    end
  end
end

default_route = Rails.application.routes.set.detect do |route|
  route.ast.to_s == '/:controller(/:action(/:id))(.:format)'
end
default_route.singleton_class.prepend(RouteSpy)