Intelligent Mirroring the Web 2.0

1 minute read


The http-protocol provides mechanisms to determine whether a Web page has changed since the last request. Leveraging this technology, web spiders and proxy servers only download modified resources, leading to a considerably better performance of Web spider architectures. Mirroring and analysis of sites leveraging Web 2.0 technologies like AJAX and dynamic HTML pose another serious challenge for current web spider architectures. Due to dynamic elements modified by JavaScript and similar technologies, simple HTML-to-text conversion techniques like lynx and html2text do not deliver usable text representations of Web documents. New approaches based on more advanced rendering architectures are required to tackle this problem.


  • extend httrack to make use of etags and Last-Modified-Headers
  • implement, test and compare crawling and archiving strategies for httrack
  • literature review: conversion of Web 2.0 sites to text.

Literature to start

  • RFC2616 (
  • httrack (
  • Jansen, B.J., Mullen, T., Spink, A. and Pedersen, J. (2006). “Automated Gathering of Web Information: An In-depth Examination of Agents Interacting with Search Engines”, ACM Transactions on Internet Technology, 6(4): 442-464.
  • Wolf, J.L., Squillante, M.S., et al. (2002). “Optimal Crawling Strategies for Web Search Engines”, 11th International Conference on World Wide Web. Honolulu, USA. 136-147.
  • Broder, A.Z., Najork, M. and Wiener, J.L. (2003). “Efficient URL Caching for World Wide Web Crawling”, 12th International World Wide Web Conference. Budapest, Hungary. 679-689.