Parsing HTTP User-Agent string

Question

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

Browser
Browser version
OS

Or perhaps any helper library that does it

More to the point, depending on browser OSes and versions for capability detection is not a good strategy. What problem are you trying to solve? — Dan Davies Brackett
– Dan Davies Brackett, Commented May 29, 2009 at 19:06
We have a simple ticket reporter form for our web app. And we frequently ask users what's the broswer/OS etc. So we might just detect it beforehand and ask the user to confirm. Well, if thats not so trivial we will just dump the user-agent but still need to ask questions, as user might be using a different browser to submit the ticket. — Shekhar
– Shekhar, Commented May 29, 2009 at 19:12
You may wish to just let Python render the form and use Javascript to change the input field values to those of the current OS and what ever else you wish. — NerdyNick
– NerdyNick, Commented May 29, 2009 at 19:23

Cody Gray · Accepted Answer · 2019-12-08 13:40:56Z

82

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'}}

edited Dec 8, 2019 at 13:40

Cody Gray♦

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answered Jul 20, 2009 at 6:24

Shekhar

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5 Comments

Jason Sundram Over a year ago

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 Over a year ago

@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 Over a year ago

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

daveoncode Over a year ago

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 :)

DS_Enthusiast Over a year ago

Is there any way to know the device name i.e desktop, iphone, ipad etc.?

Jar · Accepted Answer · 2009-08-27 09:10:50Z

10

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

answered Aug 27, 2009 at 9:10

Jar

2 Comments

Dexter Over a year ago

I would recommend UA Parser too.

Maksim Vi. Over a year ago

worth mentioning it's a paid product and a data file that is required by this product and contains user agent definitions is not availkable unless purchased. github.com/udger/udger-python/issues/5#issuecomment-739843620

Chris W. · Accepted Answer · 2014-12-24 21:08:03Z

8

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 Dec 24, 2014 at 21:08

Chris W.

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Comments

Joshua Olson · Accepted Answer · 2018-06-19 03:44:36Z

8

Werkzeug has user-agent parsing built-in.

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

edited Jun 19, 2018 at 3:44

answered Jun 21, 2012 at 23:25

Joshua Olson

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3 Comments

Shekhar Over a year ago

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.

Nova Over a year ago

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

Mohammadhzp Over a year ago

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

James Broadhead · Accepted Answer · 2012-04-11 16:35:53Z

6

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.

edited Apr 11, 2012 at 16:35

answered Apr 11, 2012 at 16:25

James Broadhead

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1 Comment

mbarkhau Over a year ago

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

Chirayu Patel · Accepted Answer · 2009-05-30 05:28:49Z

3

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

answered May 30, 2009 at 5:28

Chirayu Patel

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Comments

NerdyNick · Accepted Answer · 2009-05-29 19:25:27Z

2

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 May 29, 2009 at 19:25

NerdyNick

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Comments

Luca P. · Accepted Answer · 2020-10-27 17:38:20Z

1

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 Oct 27, 2020 at 17:38

Luca P.

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