#!/usr/bin/env python  import pickle, os, sys, loggingfrom httplib import HTTPConnection, socketfrom smtplib import SMTP def email_alert(message, status): fromaddr = 'xxx@163.com' toaddrs = 'xxxx@qq.com'  server = SMTP('smtp.163.com:25') server.starttls() server.login('xxxxx', 'xxxx') server.sendmail(fromaddr, toaddrs, 'Subject: %s/r/n%s' % (status, message)) server.quit() def get_site_status(url): response = get_response(url) try:  if getattr(response, 'status') == 200:   return 'up' except AttributeError:  pass return 'down'  def get_response(url): try:  conn = HTTPConnection(url)  conn.request('HEAD', '/')  return conn.getresponse() except socket.error:  return None except:  logging.error('Bad URL:', url)  exit(1)  def get_headers(url): response = get_response(url) try:  return getattr(response, 'getheaders')() except AttributeError:  return 'Headers unavailable' def compare_site_status(prev_results):  def is_status_changed(url):  status = get_site_status(url)  friendly_status = '%s is %s' % (url, status)  print friendly_status  if url in prev_results and prev_results[url] != status:   logging.warning(status)   email_alert(str(get_headers(url)), friendly_status)  prev_results[url] = status  return is_status_changed def is_internet_reachable(): if get_site_status('www.baidu.com') == 'down' and get_site_status('www.sohu.com') == 'down':  return False return True def load_old_results(file_path): pickledata = {} if os.path.isfile(file_path):  picklefile = open(file_path, 'rb')  pickledata = pickle.load(picklefile)  picklefile.close() return pickledata def store_results(file_path, data): output = open(file_path, 'wb') pickle.dump(data, output) output.close() def main(urls): logging.basicConfig(level=logging.WARNING, filename='checksites.log',    format='%(asctime)s %(levelname)s: %(message)s',    datefmt='%Y-%m-%d %H:%M:%S')  pickle_file = 'data.pkl' pickledata = load_old_results(pickle_file) print pickledata   if is_internet_reachable():  status_checker = compare_site_status(pickledata)  map(status_checker, urls) else:  logging.error('Either the world ended or we are not connected to the net.')   store_results(pickle_file, pickledata) if __name__ == '__main__': main(sys.argv[1:])