python domain name split name and extension

Question

How would you split a domain name that will return name and extension

Answer 1

Wow, there are a lot of bad answers here. You can only do this if you know what's on the public suffix list. If you are using split or a regex or something else, you're doing this wrong.

Luckily, this is python, and there's a library for this: https://pypi.python.org/pypi/tldextract

From their readme:

>>> import tldextract
>>> tldextract.extract('http://forums.news.cnn.com/')
ExtractResult(subdomain='forums.news', domain='cnn', suffix='com')

ExtractResult is a namedtuple. Makes it pretty easy.

The advantage of using a library like this is that they will keep up with the additions to the public suffix list so you don't have to.

Answer 2

In general, it's not easy to work out where the user-registered bit ends and the registry bit begins. For example: a.com, b.co.uk, c.us, d.ca.us, e.uk.com, f.pvt.k12.wy.us...

The nice people at Mozilla have a project dedicated to listing domain suffixes under which the public can register domains: http://publicsuffix.org/