# File lib/webby/link_validator.rb, line 140
  def validate_external_uri( uri, dir, doc )
    return unless @validate_externals

    if @invalid_uris.include? uri.to_s
      @log.error "could not open URI '#{uri.to_s}'"
      return
    end

    begin
      uri.open {|_| nil}
      @valid_uris << uri.to_s
    rescue Exception
      @log.error "could not open URI '#{uri.to_s}'"
      @invalid_uris << uri.to_s
    end 
  end