upload.rb

require 'active_support/core_ext/object/blank'

module ActionDispatch
  module Http
    module UploadedFile
      def self.extended(object)
        object.class_eval do
          attr_accessor :original_path, :content_type
          alias_method :local_path, :path if method_defined?(:path)
        end
      end

      # Take the basename of the upload's original filename.
      # This handles the full Windows paths given by Internet Explorer
      # (and perhaps other broken user agents) without affecting
      # those which give the lone filename.
      # The Windows regexp is adapted from Perl's File::Basename.
      def original_filename
        unless defined? @original_filename
          @original_filename =
            unless original_path.blank?
              if original_path =~ /^(?:.*[:\\\/])?(.*)/m
                $1
              else
                File.basename original_path
              end
            end
        end
        @original_filename
      end
    end

    module Upload
      # Convert nested Hashs to HashWithIndifferentAccess and replace
      # file upload hashs with UploadedFile objects
      def normalize_parameters(value)
        if Hash === value && value.has_key?(:tempfile)
          upload = value[:tempfile]
          upload.extend(UploadedFile)
          upload.original_path = value[:filename]
          upload.content_type = value[:type]
          upload
        else
          super
        end
      end
      private :normalize_parameters
    end
  end
end