class Sinatra::Base

def error_detection
  errmap = self.class.errors
  yield
rescue NotFound => boom
  @env['sinatra.error'] = boom
  @response.status = 404
  @response.body = ['<h1>Not Found</h1>']
  handler = errmap[boom.class] || errmap[NotFound]
  invoke handler unless handler.nil?
rescue ::Exception => boom
  @env['sinatra.error'] = boom
  if options.dump_errors?
    msg = ["#{boom.class} - #{boom.message}:", *boom.backtrace].join("\n ")
    @env['rack.errors'] << msg
  end
  raise boom if options.raise_errors?
  @response.status = 500
  invoke errmap[boom.class] || errmap[Exception]
ensure
  if @response.status >= 400 && errmap.key?(response.status)
    invoke errmap[response.status]
  end
end