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

Solution 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'}}

Solution 2

Werkzeug has user-agent parsing built-in.

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

Solution 3

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.

Solution 4

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.

Solution 5

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

View more solutions

Comments

[pythonBOI]

This doesn't seem to work particularly well for mobile phones. In particular, blackberry isn't detected. (although you got my +1 for writing it!)

[Shekhar]

@Jason Sundram If you help by providing agent strings and expected results, blackberry, others can be supported. Check github.com/shon/httpagentparser/issues

[James Broadhead]

I was interested in comparison, but that's a fair point. Retracted.

[Shekhar]

Interesting. I quickly checked the code. It is really simple, nice code essentially a series of regex to match against agent string. Interesting would be how it performs. One plus point of Werkzeug is it also detects language, while advantage of httpagentparaser is that it also detect os version.

[mbarkhau]

I think a more current version is in this repo: github.com/tobie/ua-parser

[daveoncode]

nice! I've Just wrote a django middleware for my app which prints a message to user if his browser is Internet Explorer < 10 and tested it against a lot of user agent strings... works perfectly! thank you :)

[Erik]

The current link is werkzeug.pocoo.org/docs/0.14/utils/#module-werkzeug.useragen‌​ts ; SO rejects that change for being too small.

[Mohammadhzp]

the user-agent parser is now deprecated. werkzeug.palletsprojects.com/en/2.0.x/utils/…