python 3.x - Limiting amount of time a Python3 urllib request takes: timeout not functioning as I expect -

i trying catch unresolved url given urllib request.

import urllib.request  def getsite(url):     try:         urllib.request.urlopen(url, timeout=2) r:             print(url, "was resolved!")     except:         print(url, "wasn't resolved...")     return 

i expect attempt connection url , if there no response in 2 seconds throws error , prints out isn't resolved. if resolves in under 2 seconds, response accordingly quickly. want happen. i'd each request not last more time prescribe.

as stands, using valid url provides speedy response:

> getsite('http://stackoverflow.com')  > http://stackoverflow.com resolved!     real    0m0.449s     user    0m0.063s     sys     0m0.063s 

however, using invalid url takes longer 2 seconds:

> getsite('http://thisisntarealwebaddress.com')  > http://thisisntarealwebaddress.com wasn't resolved...     real    0m18.605s     user    0m0.063s     sys     0m0.047s 

what timeout parameter doing, , how can results want?

docs: https://docs.python.org/3.1/library/urllib.request.html

i solved using run_with_limited_time_function in this answer , running function like

run_with_limited_time_function(getsite, (url, ), {}, 2) 

i'd still hear others have why timeout doesn't work way expect, though!

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copied here sanity:

def run_with_limited_time(func, args, kwargs, time):     """runs function time limit      :param func: function run     :param args: functions args, given tuple     :param kwargs: functions keywords, given dict     :param time: time limit in seconds     :return: true if function ended successfully. false if terminated.     """     p = process(target=func, args=args, kwargs=kwargs)     p.start()     p.join(time)     if p.is_alive():         p.terminate()         return false      return true