Check a date of last news at archlinux.org and compare it with saved

arch_news.py

import re
import sys
import os.path 
import datetime
import urllib.request
from os.path import expanduser


def get_news_page():
    try:
        f = urllib.request.urlopen('http://www.archlinux.org')
    except urllib.error.URLError:
        print('Cannot fetch page content, terminate.')
        sys.exit()
    else:
        return f.read()


def check_date(news_file):
    try:
        if os.path.isfile(news_file):
            with open(news_file) as f:
                saved_date = f.read()
            print('Last date is ' + saved_date)
            return datetime.datetime.strptime(saved_date, '%Y-%m-%d')
        else:
            print('Last date not found.')
            return
    except ValueError:
        print('WARNING: News file does not contain a valid date value!')
        return

def main():
    news_file = os.path.join(expanduser("~"), '.archnews')
    time_pattern = b'<p class="timestamp">(?P<timestamp>\d{4}-\d{2}-\d{2})<\/p>'
    saved_date = check_date(news_file)

    html = get_news_page()

    dt = re.search(time_pattern,html)
    last_site_date = datetime.datetime.strptime(dt.group(1).decode('utf-8'), '%Y-%m-%d')

    if not saved_date or (saved_date and saved_date < last_site_date):
        print('Check news at <http://www.archlinux.org>, please.')
        with open(news_file, 'w') as f:
            f.write(datetime.date.strftime(last_site_date, '%Y-%m-%d'))
    else:
        print('All right, you can safely update.')

if __name__ == '__main__':
    main()