open_uri_or_path (Gem::RemoteFetcher)

    # File lib/rubygems/remote_fetcher.rb, line 233
      def open_uri_or_path(uri, last_modified = nil, head = false, depth = 0)
        raise "block is dead" if block_given?

        return open(get_file_uri_path(uri)) if file_uri? uri

        uri = URI.parse uri unless URI::Generic === uri
        raise ArgumentError, 'uri is not an HTTP URI' unless URI::HTTP === uri

        fetch_type = head ? Net::HTTP::Head : Net::HTTP::Get
        response   = request uri, fetch_type, last_modified

        case response
        when Net::HTTPOK, Net::HTTPNotModified then
          head ? response : response.body
        when Net::HTTPMovedPermanently, Net::HTTPFound, Net::HTTPSeeOther,
             Net::HTTPTemporaryRedirect then
          raise FetchError.new('too many redirects', uri) if depth > 10

          open_uri_or_path(response['Location'], last_modified, head, depth + 1)
        else
          raise FetchError.new("bad response #{response.message} #{response.code}", uri)
        end
      end