    # File lib/action_controller/base.rb, line 484
          def filter_parameter_logging(*filter_words, &block)
            parameter_filter = Regexp.new(filter_words.collect{ |s| s.to_s }.join('|'), true) if filter_words.length > 0

            define_method(:filter_parameters) do |unfiltered_parameters|
              filtered_parameters = {}

              unfiltered_parameters.each do |key, value|
                if key =~ parameter_filter
                  filtered_parameters[key] = '[FILTERED]'
                elsif value.is_a?(Hash)
                  filtered_parameters[key] = filter_parameters(value)
                elsif block_given?
                  key = key.dup
                  value = value.dup if value
                  yield key, value
                  filtered_parameters[key] = value
                else
                  filtered_parameters[key] = value
                end
              end

              filtered_parameters
            end
            protected :filter_parameters
          end