从URL获取协议+主机名

You should be able to do it with urlparse (docs: python2, python3):

from urllib.parse import urlparse
# from urlparse import urlparse  # Python 2
parsed_uri = urlparse('http://stackoverflow.com/questions/1234567/blah-blah-blah-blah' )
result = '{uri.scheme}://{uri.netloc}/'.format(uri=parsed_uri)
print(result)


# gives
'http://stackoverflow.com/'

https://github.com/john-kurkowski/tldextract

This is a more verbose version of urlparse. It detects domains and subdomains for you.

From their documentation:

>>> import tldextract
>>> tldextract.extract('http://forums.news.cnn.com/')
ExtractResult(subdomain='forums.news', domain='cnn', suffix='com')
>>> tldextract.extract('http://forums.bbc.co.uk/') # United Kingdom
ExtractResult(subdomain='forums', domain='bbc', suffix='co.uk')
>>> tldextract.extract('http://www.worldbank.org.kg/') # Kyrgyzstan
ExtractResult(subdomain='www', domain='worldbank', suffix='org.kg')

ExtractResult is a namedtuple, so it's simple to access the parts you want.

>>> ext = tldextract.extract('http://forums.bbc.co.uk')
>>> ext.domain
'bbc'
>>> '.'.join(ext[:2]) # rejoin subdomain and domain
'forums.bbc'

This is a bit obtuse, but uses urlparse in both directions:

import urlparse
def uri2schemehostname(uri):
urlparse.urlunparse(urlparse.urlparse(uri)[:2] + ("",) * 4)

that odd ("",) * 4 bit is because urlparse expects a sequence of exactly len(urlparse.ParseResult._fields) = 6

Is there anything wrong with pure string operations:

url = 'http://stackoverflow.com/questions/9626535/get-domain-name-from-url'
parts = url.split('//', 1)
print parts[0]+'//'+parts[1].split('/', 1)[0]
>>> http://stackoverflow.com

If you prefer having a trailing slash appended, extend this script a bit like so:

parts = url.split('//', 1)
base = parts[0]+'//'+parts[1].split('/', 1)[0]
print base + (len(url) > len(base) and url[len(base)]=='/'and'/' or '')

That can probably be optimized a bit ...

Python3 using urlsplit:

from urllib.parse import urlsplit
url = "http://stackoverflow.com/questions/9626535/get-domain-name-from-url"
base_url = "{0.scheme}://{0.netloc}/".format(urlsplit(url))
print(base_url)
# http://stackoverflow.com/

>>> import urlparse
>>> url = 'http://stackoverflow.com/questions/1234567/blah-blah-blah-blah'
>>> urlparse.urljoin(url, '/')
'http://stackoverflow.com/'

Pure string operations :):

>>> url = "http://stackoverflow.com/questions/9626535/get-domain-name-from-url"
>>> url.split("//")[-1].split("/")[0].split('?')[0]
'stackoverflow.com'
>>> url = "stackoverflow.com/questions/9626535/get-domain-name-from-url"
>>> url.split("//")[-1].split("/")[0].split('?')[0]
'stackoverflow.com'
>>> url = "http://foo.bar?haha/whatever"
>>> url.split("//")[-1].split("/")[0].split('?')[0]
'foo.bar'

That's all, folks.

Here is a slightly improved version:

urls = [
"http://stackoverflow.com:8080/some/folder?test=/questions/9626535/get-domain-name-from-url",
"Stackoverflow.com:8080/some/folder?test=/questions/9626535/get-domain-name-from-url",
"http://stackoverflow.com/some/folder?test=/questions/9626535/get-domain-name-from-url",
"https://StackOverflow.com:8080?test=/questions/9626535/get-domain-name-from-url",
"stackoverflow.com?test=questions&v=get-domain-name-from-url"]
for url in urls:
spltAr = url.split("://");
i = (0,1)[len(spltAr)>1];
dm = spltAr[i].split("?")[0].split('/')[0].split(':')[0].lower();
print dm

Output

stackoverflow.com
stackoverflow.com
stackoverflow.com
stackoverflow.com
stackoverflow.com

Fiddle: https://pyfiddle.io/fiddle/23e4976e-88d2-4757-993e-532aa41b7bf0/?i=true

if you think your url is valid then this will work all the time

domain = "http://google.com".split("://")[1].split("/")[0]

If it contains less than 3 slashes thus you've it got and if not then we can find the occurrence between it:

import re


link = http://forum.unisoftdev.com/something


slash_count = len(re.findall("/", link))
print slash_count # output: 3


if slash_count > 2:
regex = r'\:\/\/(.*?)\/'
pattern  = re.compile(regex)
path = re.findall(pattern, url)


print path

I know it's an old question, but I too encountered it today. Solved this with an one-liner:

import re
result = re.sub(r'(.*://)?([^/?]+).*', '\g<1>\g<2>', url)

to get domain/hostname and Origin*

url = 'https://stackoverflow.com/questions/9626535/get-protocol-host-name-from-url'
hostname = url.split('/')[2] # stackoverflow.com
origin = '/'.join(url.split('/')[:3]) # https://stackoverflow.com

*Origin is used in XMLHttpRequest headers

It could be solved by re.search()

import re
url = 'https://docs.google.com/spreadsheet/ccc?key=blah-blah-blah-blah#gid=1'
result = re.search(r'^http[s]*:\/\/[\w\.]*', url).group()
print(result)


#result
'https://docs.google.com'

The standard library function urllib.parse.urlsplit() is all you need. Here is an example for Python3:

>>> import urllib.parse
>>> o = urllib.parse.urlsplit('https://user:pass@www.example.com:8080/dir/page.html?q1=test&q2=a2#anchor1')
>>> o.scheme
'https'
>>> o.netloc
'user:pass@www.example.com:8080'
>>> o.hostname
'www.example.com'
>>> o.port
8080
>>> o.path
'/dir/page.html'
>>> o.query
'q1=test&q2=a2'
>>> o.fragment
'anchor1'
>>> o.username
'user'
>>> o.password
'pass'

You can simply use urljoin with relative root '/' as second argument:

import urllib.parse




url = 'https://stackoverflow.com/questions/9626535/get-protocol-host-name-from-url'
root_url = urllib.parse.urljoin(url, '/')
print(root_url)

This is the simple way to get the root URL of any domain.

from urllib.parse import urlparse


url = urlparse('https://stackoverflow.com/questions/9626535/')
root_url = url.scheme + '://' + url.hostname
print(root_url) # https://stackoverflow.com