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

Asked By: Shekhar

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Source

Answers:

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.

Answered By: NerdyNick

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

Answered By: Chirayu Patel

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'}}
Answered By: Shekhar

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

Answered By: Jar

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.

Answered By: James Broadhead

Werkzeug has user-agent parsing built-in.

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

Answered By: Joshua Olson

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.

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.

Answered By: Chris W.

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:

Answered By: Luca Passani