gistfile1.txt

require 'open-uri'
require 'tempfile'

class Downloadable
  # The filename, *not* including the path, of the "uploaded" file
  attr_reader :original_filename

  # The content type of the "uploaded" file
  attr_accessor :content_type

  def initialize(uri, content_type = Mime::TEXT, binary = false)
    @stream = open(uri)
    @content_type = content_type
    @original_filename = File.basename( uri )
    @tempfile = Tempfile.new(@original_filename)
    @tempfile.set_encoding(Encoding::BINARY) if @tempfile.respond_to?(:set_encoding)
    @tempfile.binmode if binary
    File.open(@tempfile.path, 'wb') { |f| f.write @stream.read }
  end

  def path #:nodoc:
    @tempfile.path
  end

  alias local_path path

  def method_missing(method_name, *args, &block) #:nodoc:
    @tempfile.__send__(method_name, *args, &block)
  end
end

__END__

== How to use ==

d = Downloadable.new('http://www.google.com.ph/intl/en_com/images/logo_plain.png', 'image/png')


Photo.create! :image => d, :attachable => e