packt_notification.py

from collections import namedtuple
from datetime import datetime
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import os
import smtplib
import sys

from bs4 import BeautifulSoup as Soup
import requests

FROM_MAIL = os.environ.get('FROM_MAIL') or sys.exit('set FROM_MAIL in env')

BASE_URL = 'https://www.packtpub.com'
FREE_LEARNING_PAGE = 'free-learning'
PACKT_FREE_LEARNING_LINK = BASE_URL + '/packt/offers/' + FREE_LEARNING_PAGE

TIME_LEFT = '{} hours and {} minutes'
SUBJECT = 'Free Packt ebook of the day: {} (time left: {})'
HEADERS = {'Connection': 'keep-alive',
           'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 '
           '(KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36'}

Book = namedtuple('Book', 'title description summary image link timeleft')


def retrieve_page_html():
    if os.path.isfile(FREE_LEARNING_PAGE):
        with open(FREE_LEARNING_PAGE) as f:
            return f.read()
    else:
        return requests.get(PACKT_FREE_LEARNING_LINK, headers=HEADERS).text


def _create_time_left_string(countdown_unix_tstamp):
    expires = datetime.fromtimestamp(int(countdown_unix_tstamp))
    now = datetime.now()
    left = str(expires - now)
    hh, mm, _ = left.split(':')
    return TIME_LEFT.format(hh, mm)


def extract_book_data_page(content):
    soup = Soup(content, 'html.parser')
    book_image = soup.find('div', {'class': 'dotd-main-book-image'})
    link = BASE_URL + book_image.find('a').get('href')
    image = 'https:' + book_image.find('img').get('src')
    book_main = soup.find('div', {'class': 'dotd-main-book-summary'})
    title_div = book_main.find('div', {'class': 'dotd-title'})
    title = title_div.find('h2').text.strip()
    descr_div = title_div.find_next_sibling("div")
    description = descr_div.text.strip()
    summary_html = descr_div.find_next_sibling("div")
    # sometimes 2nd paragraph = form, then don't include it
    if 'dotd-main-book-form' in str(summary_html):
        summary_html = ''
    js_countdown = book_main.find('span', {'class': 'packt-js-countdown'})
    countdown = js_countdown.get('data-countdown-to')
    timeleft = _create_time_left_string(countdown)
    return Book(title=title,
                description=description,
                summary=summary_html,
                image=image,
                link=link,
                timeleft=timeleft)


def generate_mail_msg(book):
    return '''<h2><a href='{link}'>{title}</a></h2>
        <div>{description}</div>
        {summary_html}
        <hr>
        <img src='{image}' title='{title}'>
        <hr>
        <h2>Download</h2>
        <p>Automating Captchas sucks. Just go to 
        <a href='{url}'>{url}</a>, login and grab 
        your copy. <strong>Enjoy!</strong></p>'''.format(
                link=book.link,
                title=book.title,
                description=book.description,
                image=book.image,
                summary_html=book.summary,
                url=PACKT_FREE_LEARNING_LINK)


def mail_html(recipients, subject, content):
    sender = FROM_MAIL
    msg = MIMEMultipart('alternative')
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = ", ".join(recipients)
    part = MIMEText(content, 'html')
    msg.attach(part)
    s = smtplib.SMTP('localhost')
    s.sendmail(sender, recipients, msg.as_string())
    s.quit()


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print('Usage {} email1 email2 ...'.format(sys.argv[0]))
        sys.exit(1)

    recipients = sys.argv[1:]

    content = retrieve_page_html()
    book = extract_book_data_page(content)

    subject = SUBJECT.format(book.title, book.timeleft)
    msg_body = generate_mail_msg(book)

    mail_html(recipients, subject, msg_body)