smart_file_list.rb

require 'fileutils'
require 'Rake'

class SmartFileList < Rake::FileList
  attr_accessor :base_path

  def initialize(base_path)
    super()
    @base_path = base_path.sub(%r{/$}, "")
  end

  def extensions(*extensions)
    puts extensions
    paths = Array.new
    extensions.each do |ext|
      paths << "*.#{ext}"
    end
    include(paths)
  end
  
  def include(*filenames)

    filenames.each do |fn|
      if fn.respond_to? :to_ary
          include(*fn.to_ary)
      else
        puts "path: #{fn}"
        new_path = map_on_base_path(fn)
        puts new_path
        super new_path
      end
    end
  end

private
  def map_on_base_path(pattern)
    return "#{@base_path}/**/#{pattern}"
  end


end

usage.rb

list = SmartFileList.new("/my/path")

list.extensions("aspx", "etc")
list.exclude("obj", "whatever")

list.each do |file|
  do_whatever(file)
end