zulip/api/integrations/rss/rss-bot

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-
#
# RSS integration for Zulip
#
# Copyright © 2014 Zulip, Inc.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import calendar
import errno
import hashlib
from HTMLParser import HTMLParser
import logging
import optparse
import os
import sys
import time
from six.moves import urllib

import feedparser
import zulip
VERSION = "0.9"
RSS_DATA_DIR = os.path.expanduser(os.path.join('~', '.cache', 'zulip-rss'))
OLDNESS_THRESHOLD = 30 # days

usage = """Usage: Send summaries of RSS entries for your favorite feeds to Zulip.

This bot requires the feedparser module.

To use this script:

1. Create an RSS feed file containing 1 feed URL per line (default feed
   file location: ~/.cache/zulip-rss/rss-feeds)
2. Subscribe to the stream that will receive RSS updates (default stream: rss)
3. create a ~/.zuliprc as described on https://zulip.com/api#api_keys
4. Test the script by running it manually, like this:

/usr/local/share/zulip/integrations/rss/rss-bot

You can customize the location on the feed file and recipient stream, e.g.:

/usr/local/share/zulip/integrations/rss/rss-bot --feed-file=/path/to/my-feeds --stream=my-rss-stream

4. Configure a crontab entry for this script. A sample crontab entry for
processing feeds stored in the default location and sending to the default
stream every 5 minutes is:

*/5 * * * * /usr/local/share/zulip/integrations/rss/rss-bot"""

parser = optparse.OptionParser(usage)
parser.add_option('--stream',
                  dest='stream',
                  help='The stream to which to send RSS messages.',
                  default="rss",
                  action='store')
parser.add_option('--data-dir',
                  dest='data_dir',
                  help='The directory where feed metadata is stored',
                  default=os.path.join(RSS_DATA_DIR),
                  action='store')
parser.add_option('--feed-file',
                  dest='feed_file',
                  help='The file containing a list of RSS feed URLs to follow, one URL per line',
                  default=os.path.join(RSS_DATA_DIR, "rss-feeds"),
                  action='store')
parser.add_option_group(zulip.generate_option_group(parser))
(opts, args) = parser.parse_args()

def mkdir_p(path):
    # Python doesn't have an analog to `mkdir -p` < Python 3.2.
    try:
        os.makedirs(path)
    except OSError, e:
        if e.errno == errno.EEXIST and os.path.isdir(path):
            pass
        else:
            raise

try:
    mkdir_p(opts.data_dir)
except OSError:
    # We can't write to the logfile, so just print and give up.
    print >>sys.stderr, "Unable to store RSS data at %s." % (opts.data_dir,)
    exit(1)

log_file = os.path.join(opts.data_dir, "rss-bot.log")
log_format = "%(asctime)s: %(message)s"
logging.basicConfig(format=log_format)

formatter = logging.Formatter(log_format)
file_handler = logging.FileHandler(log_file)
file_handler.setFormatter(formatter)

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
logger.addHandler(file_handler)

def log_error_and_exit(error):
    logger.error(error)
    logger.error(usage)
    exit(1)

class MLStripper(HTMLParser):
    def __init__(self):
        self.reset()
        self.fed = []

    def handle_data(self, data):
        self.fed.append(data)

    def get_data(self):
        return ''.join(self.fed)

def strip_tags(html):
    stripper = MLStripper()
    stripper.feed(html)
    return stripper.get_data()

def compute_entry_hash(entry):
    entry_time = entry.get("published", entry.get("updated"))
    entry_id = entry.get("id", entry.get("link"))
    return hashlib.md5(entry_id + str(entry_time)).hexdigest()

def elide_subject(subject):
    MAX_TOPIC_LENGTH = 60
    if len(subject) > MAX_TOPIC_LENGTH:
        subject = subject[:MAX_TOPIC_LENGTH - 3].rstrip() + '...'
    return subject

def send_zulip(entry, feed_name):
    content = "**[%s](%s)**\n%s\n%s" % (entry.title,
                                  entry.link,
                                  strip_tags(entry.summary),
                                  entry.link)
    message = {"type": "stream",
               "sender": opts.email,
               "to": opts.stream,
               "subject": elide_subject(feed_name),
               "content": content,
               }
    return client.send_message(message)

try:
    with open(opts.feed_file, "r") as f:
        feed_urls = [feed.strip() for feed in f.readlines()]
except IOError:
    log_error_and_exit("Unable to read feed file at %s." % (opts.feed_file,))

client = zulip.Client(email=opts.email, api_key=opts.api_key,
                       site=opts.site, client="ZulipRSS/" + VERSION)

first_message = True

for feed_url in feed_urls:
    feed_file = os.path.join(opts.data_dir, urllib.parse.urlparse(feed_url).netloc)

    try:
        with open(feed_file, "r") as f:
            old_feed_hashes = dict((line.strip(), True) for line in f.readlines())
    except IOError:
        old_feed_hashes = {}

    new_hashes = []
    data = feedparser.parse(feed_url)

    for entry in data.entries:
        entry_hash = compute_entry_hash(entry)
        # An entry has either been published or updated.
        entry_time  = entry.get("published_parsed", entry.get("updated_parsed"))
        if entry_time is not None and (time.time() - calendar.timegm(entry_time)) > OLDNESS_THRESHOLD * 60 * 60 * 24:
            # As a safeguard against misbehaving feeds, don't try to process
            # entries older than some threshold.
            continue
        if entry_hash in old_feed_hashes:
            # We've already seen this. No need to process any older entries.
            break
        if (not old_feed_hashes) and (len(new_hashes) >= 3):
            # On a first run, pick up the 3 most recent entries. An RSS feed has
            # entries in reverse chronological order.
            break

        feed_name = data.feed.title or feed_url

        response = send_zulip(entry, feed_name)
        if response["result"] != "success":
            logger.error("Error processing %s" % (feed_url,))
            logger.error(response)
            if first_message:
                # This is probably some fundamental problem like the stream not
                # existing or something being misconfigured, so bail instead of
                # getting the same error for every RSS entry.
                log_error_and_exit("Failed to process first message")
        # Go ahead and move on -- perhaps this entry is corrupt.
        new_hashes.append(entry_hash)
        first_message = False

    with open(feed_file, "a") as f:
        for hash in new_hashes:
            f.write(hash + "\n")

    logger.info("Sent zulips for %d %s entries" % (len(new_hashes), feed_url))