Browsecap is a simple library for django for detecting browser type.
The main interface consists of two function in browsecap.browser:
is_mobile: returns True if the given user agent is a known mobile browser
is_crawler: returns True if the given user agent is a known crawler
For your convenience there is also a middleware that automatically redirects all mobile users to alternate domain.
To use just add browsecap.middleware.MobileRedirectMiddleware to your settings.MIDDLEWARE_CLASSES and define a MOBILE_DOMAIN that you want your mobile users redirected to. Note that the value must contain full path including the protocol (http://)
The middleware sets ismobile cookie to value 1 and can be overriden by deleting that cookie setting isbrowser cookie to 1.
Browsecap works by parsing the browscap.ini file and storing a list of browsers as regexps in memory. Each user agent to be checked is then matched against the set of regexps until we run out (False) or a match is found (True). The result is stored in a dictionary to speedup further processing of the same user agent (in our experience, 200k users only have around 8k distinct user agents, so caching works).
Performance of the matchig is adequate and shouldn't slow down the request processing even if used every time (middleware), the only thing that is somewhat slow (under a second on a laptop) is parsing the browscap.ini file. This is done only when the module is first loaded and stores it's results in cache so that start of the next thread/process should not be hindered.
You can provide your own browscap.ini file by setting BROWSCAP_DIR in django settings pointing to a directory containing the file.
It is based on henning's snippet #267 - http://www.djangosnippets.org/snippets/267/
Thank you very much for the great work!