class Sinatra::Base

def filter!(type, base = settings, &block)

Accepts an optional block to call after each filter is applied.
Run filters defined on the class and all superclasses. 
def filter!(type, base = settings, &block)
  filter!(type, base.superclass, &block) if base.superclass.respond_to?(:filters)
  base.filters[type].each do |args|
    result = process_route(*args)
    block.call(result) if block_given?
  end
end