refactor

from bs4 import BeautifulSoup

logging.basicConfig(format="%(asctime)s - %(levelname)s - %(message)s", level=logging.DEBUG)

logging.getLogger('requests').setLevel(logging.WARNING)

login = requests.session()

CONNECTED = 10001

CONNECTION_TIMEOUT = 10002

NEED_LOGIN = 10003

def load_config():

   return config

def do_login(url, username, password):

   soup_login = BeautifulSoup(login.get(url).content, 'html5lib')

   logging.info('Start to get login information')

   action = soup_login.find('form', id='fm1')['action']  # get login url

   logging.debug('action= ' + action)

   info = {}

   for element in soup_login.find('form').find_all('input'):

      if element.has_attr('value'):

         info[element['name']] = element['value']

   logging.debug(info)

   logging.info('Login information acquired.')

   info['username'] = username

   info['password'] = password

   url = 'https://cas.sustc.edu.cn{}'.format(action)

   logging.info('Login as ' + username)

   r = login.post(url, data=info, timeout=30)

   logging.info('Login information posted to the CAS server.')

   soup_response = BeautifulSoup(r.content, 'html5lib')

   success = soup_response.find('div', {'class': 'success'})

   err = soup_response.find('div', {'class': 'errors', 'id': 'msg'})

   return success, err

def test_network(url):

   try:

      test = login.get(url, timeout=30)

      content = test.content

      if test.status_code == 204:

         status = CONNECTED

      else:

         status = NEED_LOGIN

   except requests.Timeout:

      status = CONNECTION_TIMEOUT

      content = None

   return status, content

def main():

   logging.info('Program started.')

   try:

      os.chdir(os.path.dirname(sys.argv[0]))  # To read config in the same directory

   except OSError:

      pass

    logging.info('Reading configurations...')

   config = load_config()

   times_retry_login = config['max_times_retry_login']

   test_url = config['captive_portal_server']

   logging.info('Configurations successfully imported.')

   while True:

      logging.info('Checking network status...')

        try:

            login = requests.Session()

            test = login.get(test_url, timeout=30)

        except requests.RequestException:

      status, content = test_network(test_url)

      if status == CONNECTION_TIMEOUT:

         logging.info('Connection FAILED. Try again in ' + str(config['interval_retry_connection']) + ' sec.')

         sleep(config['interval_retry_connection'])

         continue

        while test.status_code != 204:

            soup_login = BeautifulSoup(test.content, 'html5lib')

      while status == NEED_LOGIN:

         soup_login = BeautifulSoup(content, 'html5lib')

         if 'CAS' not in soup_login.title.string:

            logging.warning('Not connected to a SUSTC network')

            sleep(config['interval_retry_connection'])

         logging.info('You are offline. Starting login...')

         hostname = 'http://enet.10000.gd.cn:10001/sz/sz112/'

            rem_link = re.search(r'window\.location = \'(.*)\';', test.text).group(1)

         rem_link = re.search(r'window\.location = \'(.*)\';', soup_login.text).group(1)

         url = hostname + rem_link

            soup_login = BeautifulSoup(login.get(url).content, 'html5lib')

            logging.info('Start to get login information')

            action = soup_login.find('form', id='fm1')['action']  # get login url

            logging.debug('action= ' + action)

         success, err = do_login(url, config['username'], config['password'])

            info = {}

            for element in soup_login.find('form').find_all('input'):

                if element.has_attr('value'):

                    info[element['name']] = element['value']

            logging.debug(info)

            logging.info('Login information acquired.')

            info['username'] = config['username']

            info['password'] = config['password']

            url = 'https://cas.sustc.edu.cn{}'.format(action)

            h = {

                'Cache-Control': 'max-age=0',

                'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',

                'Origin': 'http://cas.sustc.edu.cn',

                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36',

                'Content-Type': 'application/x-www-form-urlencoded',

                'DNT': '1',

                'Referer': url,

                'Accept-Encoding': 'gzip, deflate',

                'Accept-Language': 'en-US,en;q=0.8,zh-CN;q=0.6,zh;q=0.4'

            }

            logging.info('Login as ' + config['username'])

            r = login.post(url, data=info, headers=h, timeout=30)

            logging.info('Login information posted to the CAS server.')

            soup_response = BeautifulSoup(r.content, 'html5lib')

            success = soup_response.find('div', {'class': 'success'})

            err = soup_response.find('div', {'class': 'errors'})

         if err:

            times_retry_login -= 1

                logging.error('An error occurred.')

                logging.error(err.h2.text)

                logging.error(err.p.text)

            logging.error('Error occurred: ' + err.text)

            if times_retry_login > 0:

               # If keep trying to login too many times, it may trigger security alarm on the CAS server

               logging.info(

                     .format(time=config['interval_retry_login'], attempt=times_retry_login))

            else:

               logging.info('Login FAILED. Attempts used up. The program will quit.')

                    sys.exit('Login FAILED')

               sys.exit(1)

            sleep(config['interval_retry_login'])

         elif success:

Java version with GUI (discontinued): [caslogin-gui](https://github.com/CubicPill/caslogin-gui)

## Requirements

Python2.7+

requests==2.11.1

requests==2.11.

beautifulsoup4==4.5.3

## Configuration items