paperclip attachment remote file download

paperclip.rb

require 'open-uri'

def get_file(url)
  filename = url.split("/").last.gsub(/_[0-9a-f\-]{36}\./,".")
  begin
    file = open( url )
    file.instance_variable_set(:@original_filename, filename)
    def file.original_filename; @original_filename; end
    file
  rescue OpenURI::HTTPError
    nil
  end
end

# Usage
m = PaperclipModel.new
m.attachment = get_file("http://some-place-with-a-file/")
m.save!