How to See If There's an Available and Active Network Connection in Python

How can I see if there's an available and active network connection in Python?

Perhaps you could use something like this:

import urllib2

def internet_on():
    try:
        urllib2.urlopen('http://216.58.192.142', timeout=1)
        return True
    except urllib2.URLError as err: 
        return False

Currently, 216.58.192.142 is one of the IP addresses for google.com. Change http://216.58.192.142 to whatever site can be expected to respond quickly.

This fixed IP will not map to google.com forever. So this code is
not robust -- it will need constant maintenance to keep it working.

The reason why the code above uses a fixed IP address instead of fully qualified domain name (FQDN) is because a FQDN would require a DNS lookup. When the machine does not have a working internet connection, the DNS lookup itself may block the call to urllib_request.urlopen for more than a second. Thanks to @rzetterberg for pointing this out.

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If the fixed IP address above is not working, you can find a current IP address for google.com (on unix) by running

% dig google.com  +trace 
...
google.com.     300 IN  A   216.58.192.142

Test if an internet connection is present in python

My approach would be something like this:

import socket
REMOTE_SERVER = "one.one.one.one"
def is_connected(hostname):
  try:
    # see if we can resolve the host name -- tells us if there is
    # a DNS listening
    host = socket.gethostbyname(hostname)
    # connect to the host -- tells us if the host is actually reachable
    s = socket.create_connection((host, 80), 2)
    s.close()
    return True
  except Exception:
     pass # we ignore any errors, returning False
  return False
%timeit is_connected(REMOTE_SERVER)
> 31.9 ms ± 627 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)

This will return within less than a second if there is no connection (Linux, Python 3.8).

Note: This test can return false positives -- e.g. the DNS lookup may return a server within the local network. To be really sure you are connected to the internet, and talking to a valid host, be sure to use more sophisticated methods (e.g. SSL).

Checking internet connection with Python

you should do something like

def check_internet():
    for timeout in [1,5,10,15]:
        try:
            print "checking internet connection.."
            socket.setdefaulttimeout(timeout)
            host = socket.gethostbyname("www.google.com")
            s = socket.create_connection((host, 80), 2)
            s.close()
            print 'internet on.'
            return True

        except Exception,e:
            print e
            print "internet off."
    return False

or even better (mostly taken from other answer linked in comments)

def internet_on():
    for timeout in [1,5,10,15]:
        try:
            response=urllib2.urlopen('http://google.com',timeout=timeout)
            return True
        except urllib2.URLError as err: pass
    return False

How to check if user is connected to internet in python?

You could do something like this where you check for connection to a site.

import urllib.request 
import urllib.parse 

try: 
    x = urllib.request.urlopen('https://www.google.com')        
except Exception as e: 
    print(str(e)) 

python wait until connection active

Definitely don't do it recursively. Use a loop instead:

def wait_for_internet_connection():
    while True:
        try:
            response = urllib2.urlopen('http://74.125.113.99',timeout=1)
            return
        except urllib2.URLError:
            pass

def main():
    ...

wait_for_internet_connection()
main()

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