robot_detection is a python module to detect if a given HTTP User Agent is a web crawler. It uses the list of registered robots from http://www.robotstxt.org: (Robots Database)[http://www.robotstxt.org/db.html)
There is only one, function, is_robot that takes a string (unicode or not) and returns True iff that string matches a known robot in the robotstxt.org robot database
>>> import robot_detection
>>> robot_detection.is_robot(user_agent_string)
You can download a new version of the Robot Database from this link.
Download the database dump, and run the file robot_detection.py with the file as first argument.
$ wget http://www.robotstxt.org/db/all.txt
$ python robot_detection.py all.txt
If the database has changed, it'll print out the new version of robot_useragents variable that you need to put into the source code.
Some simple unittests are included. Running the tests.py file will run the tests.