11.5 Popular Redirectors

As I already mentioned, the Squid source code doesn't include any redirectors. However, you can find a number of useful third-party redirectors linked from the Related Software page on http://www.squid-cache.org. Here are some of the more popular offerings:

11.5.1 Squirm

http://squirm.foote.com.au/

Squirm comes from Chris Foote. It is written in C and distributed as source code under the GNU General Public License (GPL). Squirm's features include:

• Being very fast with minimal memory usage

• Full regular expression pattern matching and replacement

• Ability to apply different redirection lists to different client groups

• Interactive mode for testing on the command line

• Fail-safe mode passes requests through unchanged in the event that configuration files contain errors

• Writing debugging, errors, and more to various log files

11.5.2 Jesred

http://www.linofee.org/~elkner/webtools/jesred/

Jesred comes from Jens Elkner. It is written in C, based on Squirm, and also released under the GNU GPL. Its features include:

• Being faster than Squirm, with slightly more memory usage

• Ability to reread its configuration files while running

• Full regular expression pattern matching and replacement

• Fail-safe mode passes requests through unchanged in the event that configuration files contain errors

• Optionally logging rewritten requests to a log file

11.5.3 squidGuard

http://www.squidguard.org/

squidGuard comes from Pål Baltzersen and Lars Erik Håland at Tele Danmark InterNordia. It is released under the GNU GPL. The authors also make sure squidGuard compiles easily on modern Unix systems. Their site contains a lot of good documentation. Here are some of squidGuard's features:

• Highly configurable; you can apply different rules to different groups of clients or users and at different times or days

• URI substitution, not just replacement, à la sed

• printf-like substitutions allow passing parameters to CGI scripts for customized messages

• Supportive of the 301/302/303/307 HTTP redirect status code feature for redirectors

• Selective logging for rewrite rule sets

At the squidGuard site, you can also find a blacklist of more than 100,000 sites categorized as porn, aggressive, drugs, hacking, ads, and more.

11.5.4 AdZapper

http://www.adzapper.sourceforge.net

AdZapper is a popular redirector because it specifically targets removal of advertisements from HTML pages. It is a Perl script written by Cameron Simpson. AdZapper can block banners (images), pop-up windows, flash animations, page counters, and web bugs. The script includes a list of regular expressions that match URIs known to contain ads, pop-ups, etc. Cameron updates the script periodically with new patterns. You can also maintain your own list of patterns.