tg_rss_bot/database.py

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import sqlite3
from exceptions import DisplayableException
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from rss import FeedItem
class Database:
"""Implement interaction with the database."""
def __init__(self, path: str) -> None:
"""Create a database file if not exists."""
# TODO: think about removing check_same_thread=False
self.conn = sqlite3.connect(path, check_same_thread=False)
self.conn.row_factory = sqlite3.Row
self.cur = self.conn.cursor()
self.__init_schema()
def add_user(self, telegram_id: int) -> int:
"""Add a user's telegram id to the database and return its database id."""
self.cur.execute('INSERT INTO users (telegram_id) VALUES (?)', [telegram_id])
self.conn.commit()
return self.cur.lastrowid
def find_user(self, telegram_id: int) -> int | None:
"""Get a user's telegram id and return its database id."""
self.cur.execute('SELECT id FROM users WHERE telegram_id = ?', [telegram_id])
row = self.cur.fetchone()
if row is None:
return None
return row['id']
def add_feed(self, url: str) -> int:
"""Add a feed to the database and return its id."""
self.cur.execute('INSERT INTO feeds (url) VALUES (?)', [url])
self.conn.commit()
return self.cur.lastrowid
def find_feed_by_url(self, url: str) -> int | None:
"""Find feed ID by url."""
self.cur.execute('SELECT id FROM feeds WHERE url = ?', [url])
row = self.cur.fetchone()
if row is None:
return None
return row['id']
def subscribe_user_by_url(self, user_id: int, url: str) -> None:
"""Subscribe user to the feed creating it if does not exist yet."""
feed_id = self.find_feed_by_url(url)
if feed_id is None:
feed_id = self.add_feed(url)
if self.is_user_subscribed(user_id, feed_id):
raise DisplayableException('Already subscribed')
self.subscribe_user(user_id, feed_id)
def subscribe_user(self, user_id: int, feed_id: int) -> None:
"""Subscribe a user to the feed."""
self.cur.execute('INSERT INTO subscriptions (user_id, feed_id) VALUES (?, ?)', [user_id, feed_id])
self.conn.commit()
def unsubscribe_user_by_url(self, user_id: int, url: str) -> None:
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"""Subscribe a user to the feed by url."""
feed_id = self.find_feed_by_url(url)
if feed_id is None:
raise DisplayableException('Feed does not exist')
if not self.is_user_subscribed(user_id, feed_id):
raise DisplayableException('Not subscribed')
self.unsubscribe_user(user_id, feed_id)
if self.get_feed_subscribers_count(feed_id) == 0:
# Feed is not used anymore. Removing.
self.delete_feed(feed_id)
def unsubscribe_user(self, user_id: int, feed_id: int) -> None:
"""Unsubscribe a user from the feed."""
self.cur.execute('DELETE FROM subscriptions WHERE feed_id = ? AND user_id = ?', [feed_id, user_id])
self.conn.commit()
def is_user_subscribed(self, user_id: int, feed_id: int) -> bool:
"""Check if user subscribed to specific feed."""
self.cur.execute('SELECT 1 FROM subscriptions WHERE user_id = ? AND feed_id = ?', [user_id, feed_id])
row = self.cur.fetchone()
if row is None:
return False
return True
def delete_feed(self, feed_id: int) -> None:
"""Delete a feed."""
self.cur.execute('DELETE FROM feeds WHERE id = ?', [feed_id])
self.conn.commit()
def get_feed_subscribers_count(self, feed_id: int) -> int:
"""Count feed subscribers."""
self.cur.execute('SELECT COUNT(user_id) AS amount_subscribers FROM subscriptions WHERE feed_id = ?', [feed_id])
row = self.cur.fetchone()
return row['amount_subscribers']
def find_feed_subscribers(self, feed_id: int) -> list[int]:
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"""Return feed subscribers"""
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self.cur.execute('SELECT telegram_id FROM users WHERE id IN (SELECT user_id FROM subscriptions WHERE feed_id = ?)',
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[feed_id])
subscribers = self.cur.fetchall()
return list(map(lambda x: x['telegram_id'], subscribers))
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def find_feeds(self) -> list[sqlite3.Row]:
"""Get a list of feeds."""
self.cur.execute('SELECT * FROM feeds')
return self.cur.fetchall()
def find_user_feeds(self, user_id: int) -> list[sqlite3.Row]:
"""Return a list of feeds the user is subscribed to."""
self.cur.execute('SELECT * FROM feeds WHERE id IN (SELECT feed_id FROM subscriptions WHERE user_id = ?)',
[user_id])
return self.cur.fetchall()
def find_feed_items(self, feed_id: int) -> list[sqlite3.Row]:
"""Get last feed items."""
self.cur.execute('SELECT * FROM feeds_last_items WHERE feed_id = ?', [feed_id])
return self.cur.fetchall()
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def find_feed_items_urls(self, feed_id: int) -> list[str]:
"""Return urls last feed items"""
items = self.find_feed_items(feed_id)
if not items:
return items
return list(map(lambda x: x['url'], items))
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def update_feed_items(self, feed_id: int, new_items: list[FeedItem]) -> None:
"""Replace last feed items with a list items that receive."""
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for i, _ in enumerate(new_items):
new_items[i] = [feed_id] + list(new_items[i].__dict__.values())[:-1]
self.cur.execute('DELETE FROM feeds_last_items WHERE feed_id = ?', [feed_id])
self.cur.executemany(
'INSERT INTO feeds_last_items (feed_id, url, title, description) VALUES (?, ?, ?, ?)', new_items)
self.conn.commit()
def __init_schema(self):
# TODO: Move to migrations
self.cur.execute(
'CREATE TABLE IF NOT EXISTS users (id INTEGER, telegram_id INTEGER NOT NULL UNIQUE, PRIMARY KEY(id))'
)
self.cur.execute('CREATE TABLE IF NOT EXISTS feeds (id INTEGER, url TEXT NOT NULL UNIQUE, PRIMARY KEY(id))')
self.cur.execute(
'CREATE TABLE IF NOT EXISTS subscriptions ('
' user_id INTEGER,'
' feed_id INTEGER,'
' UNIQUE (user_id, feed_id),'
' FOREIGN KEY(user_id) REFERENCES users(id),'
' FOREIGN KEY(feed_id) REFERENCES feeds(id)'
')'
)
self.cur.execute(
'CREATE TABLE IF NOT EXISTS feeds_last_items ('
' feed_id INTEGER,'
' url TEXT NOT NULL UNIQUE,'
' title TEXT,'
' description TEXT,'
' FOREIGN KEY(feed_id) REFERENCES feeds(id)'
')'
)