Parsing HTTP User-Agent string

Question

What is the best method to parse a User-Agent string in Python to reliably detect

1. Browser
2. Browser version
3. OS

Or perhaps any helper library that does it

Answer 1

I finally decided to write my own, and I am happy with the outcome. Please feel free to use/modify/send me patches, etc.

It's here: http://pypi.python.org/pypi/httpagentparser

Usage example:

>>> import httpagentparser
>>> s = "Mozilla/5.0 (X11; U; Linux i686; en-US) AppleWebKit/532.9 (KHTML, like Gecko) \
        Chrome/5.0.307.11 Safari/532.9"
>>> print(httpagentparser.simple_detect(s))
('Linux', 'Chrome 5.0.307.11')
>>> print(httpagentparser.detect(s))
{'os': {'name': 'Linux'},
 'browser': {'version': '5.0.307.11', 'name': 'Chrome'}}

>>> s = "Mozilla/5.0 (Linux; U; Android 2.3.5; en-in; HTC_DesireS_S510e Build/GRJ90) \
        AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1"
>>> print(httpagentparser.simple_detect(s))
('Android Linux 2.3.5', 'Safari 4.0')
>>> print(httpagentparser.detect(s))
{'dist': {'version': '2.3.5', 'name': 'Android'},
'os': {'name': 'Linux'},
'browser': {'version': '4.0', 'name': 'Safari'}}

Answer 2

UASparser for Python by Hicro Kee. Auto updated datafile and cache from remote server with version checking.

Answer 3

Werkzeug has user-agent parsing built-in.

New link (Jun 2018) http://werkzeug.pocoo.org/docs/0.14/utils/#module-werkzeug.useragents

Answer 4

The other responses to this question are rather old now. I believe the new standard in Browser User Agent parsing is Browserscope's user agent parser .

• UA Parser pypi package
• UA Parser on github

Also conveniently available with the exact same matching patterns in many other languages . Someday you might want to also parse some UA strings in JavaScript and you don't need to worry about inconsistent parsing.

Answer 5

Having run these suggestions against the full corpus of Firefox User Agents , I've found that the version-number parsing for comparison is quite poor.

If that's what you need, I suggest that you take a look at UAparser , which used to be part of the browserscope project. Documentation here.

Answer 6

Th Browser Cap Parser should work. It may be a bit slow though..

Answer 7

However if you wish to parse all this on the Python side you can use the XML/INI files provided at http://browsers.garykeith.com/downloads.asp to do lookups on the user agent. This is the same file that is used in php's get_browser() function.

Answer 8

As this is not about an open source solution, I doubt this will become the first answer. Anyway, when it comes to User-Agent analysis, the de-facto standard is WURFL (now a commercial product.

Here is a reference to the technical docs.

https://docs.scientiamobile.com/documentation/infuze/infuze-python-module-user-guide

In addition to that, WURFL Microservice is available on the major Cloud Providers marketplaces and also supports a Python client :