Information-Hiding URLs for Easier Website Evolution

Abstract

Many common elements of URLs do not adhere to the principle of information hiding. For example, filename extensions and parameter names can reveal volatile implementation details. As a result, when website implementations change, links between pages break. Bookmarks and code that generates URLs often break as well. In this paper, we present two tools for information-hiding URLs. An information-hiding URL uses an alias to identify a web resource and appends parameter values into the hierarchical structure of the URL. The InformationHidingFilter uses a Java Servlet filter to facilitate the use of informationhiding URLs with JSP/Servlet web applications. Given a request, the filter identifies the JSP or Servlet being requested and identifies parameter values contained in the information-hiding URL. Required values not provided in the URL are automatically substituted with default values specified by the web developer. Thus, old links remain valid even when the website changes and new parameters have been added to the page. The InformationHidingChecker helps web developers adhere to information hiding by helping them identify JSPs or Servlets that lack URL information for the InformationHidingFilter or lack default values for parameters. We also discuss the performance cost of using information-hiding URLs.