I am investigating the possibilities of screen scraping/web extraction/ automated web navigation/wrapper generation in Ruby. I have been working with these technologies for several years, (unfortunately) in Java and partially C/C++ only. I came to know Ruby a few months ago and I am currently investigating the existing tools for the above tasks. Since i have the feeling that i am not alone (this topic is brought up regularly here, maybe not as often as the "how to create an Object from it's name", but it is close to that ;-) I have summarized my findings (tools that i have found, descriptions, examples, comparison etc.), maybe can help someone.
You can find simple example solutions of the same problem (scraping links from a google result page) with regular expressions, HTree+REXML, RubyfulSoup and WWW::Mechanize.
I am planning to write more entries on this topic, involving screen scraping from Rails, Gecko to Ruby GTK widget embedding, wrapper generation etc. Please note that i am new to Ruby so it is possible that my code snippets are not the most optimal yet (suggestions welcome), but they are all tested and working.
Feedback/corrections/suggestions would be very much appreciated!