class Sinatra::Base

def handle_not_found!(boom)

Special treatment for 404s in order to play nice with cascades. 
def handle_not_found!(boom)
  @env['sinatra.error']          = boom
  @response.status               = 404
  @response.headers['X-Cascade'] = 'pass'
  @response.body                 = ['<h1>Not Found</h1>']
  error_block! boom.class, NotFound
end