announce.py

#! /usr/bin/env python3
# -*- coding: utf-8 -*-
# Relays news entries to the announce mailing list.
# To be run with minimal privileges shortly after every full hour.

# Initial version, 10/2010:
#     B. Hof <hof@stusta.net>
# Made a little bit less unbelievably insane, 04/2012:
#     B. Braun <benjamin.braun@stusta.net>,
#     T. Klenze <tobias.klenze@stusta.net>
# Fixed stuff, 06/2016:
#     J. Schmidt <js@stusta.net>
# Fixed AM/PM handling, 02/2017
#     C. Winter <christian.winter@stusta.net>
# Complete rewrite in python3 using the API, 04/2018
#     J. Schmidt <js@stusta.net>
# Added nextcloud calendar integration
#     T. Jülg <tj@stusta.de>

import configparser
import smtplib
import sys
import os
import re
import urllib.parse
from datetime import datetime, timedelta
from email.utils import make_msgid, formatdate, formataddr
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import caldav
import mwclient
import pytz
from bs4 import BeautifulSoup
from ics import Event, Calendar


def event2cal(calendar):
    config = configparser.RawConfigParser()
    config.read(os.path.dirname(os.path.realpath(__file__)) + '/announce.ini')
    cfg = config.get

    url = cfg('cal_dav', 'dav_url')
    username = cfg('cal_dav', 'dav_user')
    password = cfg('cal_dav', 'dav_password')
    client = caldav.DAVClient(url=url, username=username, password=password)
    stustanet_calendar = client.calendar(url=cfg('cal_dav', 'calendar_url'))
    stustanet_calendar.save_event(str(calendar))


def format_news(entry, page):
    content = page.text()
    content = content.replace("{{!}}", "")
    content = content.split("\n}}\n")

    text = ""
    body = ""
    for item in content:
        if item.startswith("{{StuStaNet-News"):
            continue
        if item.startswith("{{Termin"):
            start = ""
            end = ""
            location = ""
            lines = item.splitlines()
            for line in lines:
                if line.startswith("|von="):
                    start = line[5:]
                elif line.startswith("|bis="):
                    end = line[5:]
                elif line.startswith("|Ort="):
                    location = line[5:]
            if start != "":
                body += "Datum: " + start
                if end != "":
                    body += " bis " + end
                body += "\n"
            if location != "":
                body += "Ort: " + location + "\n"

        else:
            text += item + "\n"

    calendar = None
    try:
        tz = pytz.timezone('Europe/Berlin')
        starttime = tz.localize(datetime.strptime(start, "%Y/%m/%d %H:%M:%S"))
        event = Event()
        event.name = entry['Titel']
        event.begin = starttime
        try:
            endtime = tz.localize(datetime.strptime(end, "%Y/%m/%d %H:%M:%S"))
        except ValueError:
            # default to 2 hours duration
            endtime = starttime + timedelta(hours=2)
        event.end = endtime
        if location != "":
            event.location = location
        tmp = page.text()
        ms = [re.search(r"\|Zusammenfassung=(.*)", line)
              for line in tmp.split('\n')]
        ms = [m for m in ms if m is not None]
        if len(ms) > 0:
            event.description = ms[0].groups()[0]

        calendar = Calendar()
        calendar.events.add(event)
    except ValueError:
        print(f"Value error: couldn't parse date {start}")
        calendar = None

    body += "Zusammenfassung:\n"
    body += entry['Zusammenfassung']
    body += "\n\n\n"

    text = ''.join(BeautifulSoup(
        text, "html.parser").findAll(text=True)).strip()
    body += text

    body += "\n\n\n"
    body += "Quelle: https://wiki.stusta.de/" + \
        urllib.parse.quote(entry['Page'].replace(" ", "_"))
    body += "\n\n-- \nMehr Informationen: https://info.stusta.de\n"
    return (body, calendar)


def attach_calendar(msg, calendar):
    ical_atch = MIMEText(str(calendar).encode("utf-8"), 'calendar', 'utf-8')
    ical_atch.add_header('Content-Disposition',
                         'attachment; filename="invite.ics"')
    msg.attach(ical_atch)


# send mail to announce list
def send_mail(subject, author, body, calendar=None):
    print("Sending Announce Email:", subject)
    from_addr = "no-reply@stusta.mhn.de"
    from_domain = from_addr.split('@')[1]
    to_addr = "announce@lists.stusta.mhn.de"

    msg = MIMEMultipart()
    msg['date'] = formatdate(localtime=True)

    msg['subject'] = subject
    msg['from'] = formataddr((author, from_addr))
    msg['to'] = to_addr
    msg['reply-to'] = "StuStaNet e. V. Admins <admins@lists.stusta.mhn.de>"
    msg['Message-ID'] = make_msgid(domain=from_domain)

    msg.attach(MIMEText(body, 'plain'))

    if calendar:
        attach_calendar(msg, calendar)

    smtp = smtplib.SMTP('mail.stusta.de')
    smtp.sendmail(from_addr, to_addr, msg.as_string())
    smtp.quit()


def main():
    site = mwclient.Site('wiki.stusta.de', path='/')

    # get stustanet news which should be announce between 55 minutes ago and in 5 minutes
    # If the script is run every hour, every announce is sent exactly once
    results = site.get('cargoquery',
                       tables='News',
                       fields='_pageName=Page,Titel,Autor,Zusammenfassung,Datum',
                       where='Infoseite=1 AND Kategorie="StuStaNet"'
                             'AND TIMESTAMPDIFF(MINUTE,NOW(),Datum)<=5 AND TIMESTAMPDIFF(MINUTE,NOW(),Datum)>-55',
                       order_by='Datum ASC',
                       format='json',
                       )

    for res in results['cargoquery']:
        entry = res['title']
        author = entry['Autor']
        if author == "":
            author = "Infoseite"
        subject = entry['Titel']
        body, calendar = format_news(entry, site.pages[entry['Page']])
        # create event in stustanet calendar
        event2cal(calendar)
        # send mails to announce
        send_mail(subject, author, body, calendar)


if __name__ == '__main__':
    sys.exit(main())