tg_rss_bot/update_manager.py

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from logging import Logger
from rss import RssReader, FeedItem
from database import Database
from telegram import Notifier
class UpdateManager:
"""Implement the feed update."""
def __init__(self, database: Database, notifier: Notifier, rss_reader: RssReader, logger: Logger) -> None:
self.log: Logger = logger
self.log.debug(
'UpdateManager.__init__(database=%s, notifier=%s, rss_reader=%s, logger=%s)',
database, notifier, rss_reader, logger
)
self.database: Database = database
self.notifier: Notifier = notifier
self.rss_reader: RssReader = rss_reader
def update(self):
"""Send new feed items to the user."""
self.log.info('Running update')
feeds = self.database.find_feeds()
self.log.info('Feeds to update: %d', len(feeds))
for feed in feeds:
self.log.info('Processing [%d] %s', feed['id'], feed['url'])
feed_obj = self.rss_reader.get_feed(feed['url'])
new_items = feed_obj.items
old_items = self.database.find_feed_items(feed['id'])
diff = self.__calculate_difference(new_items, old_items)
if not diff:
continue
chat_ids = self.database.find_feed_subscribers(feed['id'])
self.notifier.send_updates(chat_ids, diff, feed_obj.title)
self.database.update_feed_items(feed['id'], new_items)
def __calculate_difference(self, new_items: list[FeedItem], old_items: list[dict]) -> list[FeedItem]:
"""Calculate new feed items."""
self.log.debug(
'__calculate_difference(new_items=list(%d), old_items=list(%d))', len(new_items), len(old_items)
)
if not old_items:
self.log.debug('Old items are empty, returning new')
return new_items
diff = []
guids = [item['guid'] for item in old_items if item['guid']]
urls = [item['url'] for item in old_items]
self.log.debug('Comparing %d new items with %d old', len(new_items), len(old_items))
for item in new_items:
if not guids and item.url not in urls:
diff.append(item)
continue
if item.guid not in guids:
diff.append(item)
self.log.debug('%d updates found', len(diff))
return diff