auto_reconnect.py

# Monitor Internet Connection #
import os
import sys
import time
import datetime
import argparse

RECONNECT_COMMAND = """
networksetup -setairportpower en0 off;
sleep 1;
networksetup -setairportpower en0 on;
"""

HAS_INTERNET_COMMAND = """
curl -i --connect-timeout 3 --max-time 5 www.google.com 1> stdout.txt 2> stderr.txt;
TEMP_OUTPUT=$(cat stdout.txt | grep "HTTP/1.1 200 OK")
if [ -n "$TEMP_OUTPUT" ]
then
  exit 0;
fi
exit 1;
"""

def time_stamp():
	return datetime.datetime.fromtimestamp(time.time()).strftime('%Y-%m-%d %H:%M:%S')

# return 0 if okay
# assume error if not 0
def check_internet():
	return interruptible_command(HAS_INTERNET_COMMAND)

def reconnect_to_internet():
	os.system(RECONNECT_COMMAND)

def interruptible_command(com_str):
	try:
		return_value = os.system(com_str)
		if return_value == 2:
			raise KeyboardInterrupt()
		return return_value
	except KeyboardInterrupt, e:
		raise e

def monitor_connection(verbose=True, interval=0.5):
	counter = 0
	print "Beginnning Monitor (interval: {0} sec)...".format(interval)
	while True:
		time.sleep(interval)
		counter = counter + 1
		sys.stdout.write('\r' + str(counter) + ' ticks')
		sys.stdout.flush()
		if check_internet() != 0:
			print ''
			print '---'
			print 'internet lost, waiting 2 sec for reconnect...'
			time.sleep(2.0)
			if check_internet() != 0:
				print 'internet still lost, force reconnect...'
				print 'counter = 0'
				counter = 0
				reconnect_to_internet()
				print 'wait for 2 sec before beginning loop...'
				time.sleep(2.0)
			print '---'

if __name__ == '__main__':
	parser = argparse.ArgumentParser(description='Automatically reconnect if internet connection is lost')
	parser.add_argument('--interval', '-i', type=float, default=0.5, help='Interval time (default: 0.5 sec)')
	parser.add_argument('--verbose', '-v', action='store_true')
	args = parser.parse_args()
	try:
		monitor_connection(verbose=args.verbose, interval=args.interval)
	except KeyboardInterrupt, e:
		print "\n\nQuitting now..."