Bump version to 0.4.1

Stabilize entry IDs

.github/workflows/python-lint.yml

@@ -0,0 +1,25 @@
+name: Python lint
+
+on: [push, pull_request]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/setup-python@v3
+      with:
+        python-version: "3.13"
+    - uses: isort/isort-action@master
+      with:
+        sortPaths: "./rss"
+    - uses: psf/black@stable
+      with:
+        src: "./rss"
+    - name: pre-commit
+      run: |
+        pip install pre-commit
+        pre-commit run -av trailing-whitespace
+        pre-commit run -av end-of-file-fixer
+        pre-commit run -av check-yaml
+        pre-commit run -av check-added-large-files

.gitlab-ci.yml

@@ -1,27 +1,3 @@
-image: dock.mau.dev/maubot/maubot
-
-stages:
-- build
-
-variables:
-  PYTHONPATH: /opt/maubot
-
-build:
-  stage: build
-  except:
-  - tags
-  script:
-  - python3 -m maubot.cli build -o xyz.maubot.$CI_PROJECT_NAME-$CI_COMMIT_REF_NAME-$CI_COMMIT_SHORT_SHA.mbp
-  artifacts:
-    paths:
-    - "*.mbp"
-
-build tags:
-  stage: build
-  only:
-  - tags
-  script:
-  - python3 -m maubot.cli build -o xyz.maubot.$CI_PROJECT_NAME-$CI_COMMIT_TAG.mbp
-  artifacts:
-    paths:
-    - "*.mbp"
+include:
+- project: 'maubot/maubot'
+  file: '/.gitlab-ci-plugin.yml'

.pre-commit-config.yaml

@@ -0,0 +1,20 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: trailing-whitespace
+        exclude_types: [markdown]
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-added-large-files
+  - repo: https://github.com/psf/black
+    rev: 25.1.0
+    hooks:
+      - id: black
+        language_version: python3
+        files: ^rss/.*\.pyi?$
+  - repo: https://github.com/PyCQA/isort
+    rev: 6.0.0
+    hooks:
+      - id: isort
+        files: ^rss/.*\.pyi?$

README.md

@@ -1,2 +1,30 @@
 # rss
 A [maubot](https://github.com/maubot/maubot) that posts RSS feed updates to Matrix.
+
+## Usage
+Basic commands:
+
+* `!rss subscribe <url>` - Subscribe the current room to a feed.
+* `!rss unsubscribe <feed ID>` - Unsubscribe the current room from a feed.
+* `!rss subscriptions` - List subscriptions (and feed IDs) in the current room.
+* `!rss notice <feed ID> [true/false]` - Set whether the bot should send new
+  posts as `m.notice` (if false, they're sent as `m.text`).
+* `!rss template <feed ID> [new template]` - Change the post template for a
+  feed in the current room. If the new template is omitted, the bot replies
+  with the current template.
+
+### Templates
+The default template is `New post in $feed_title: [$title]($link)`.
+
+Templates are interpreted as markdown with some simple variable substitution.
+The following variables are available:
+
+* `$feed_url` - The URL that was used to subscribe to the feed.
+* `$feed_link` - The home page of the feed.
+* `$feed_title` - The title of the feed.
+* `$feed_subtitle` - The subtitle of the feed.
+* `$id` - The unique ID of the entry.
+* `$date` - The date of the entry.
+* `$title` - The title of the entry.
+* `$summary` - The summary/description of the entry.
+* `$link` - The link of the entry.

base-config.yaml

@@ -1,11 +1,15 @@
 # Feed update interval in minutes
 update_interval: 60
+# Maximum backoff in minutes when failing to fetch feeds (defaults to 5 days)
+max_backoff: 7200
 # The time to sleep between send requests when broadcasting a new feed entry.
 # Set to 0 to disable sleep or -1 to run all requests asynchronously at once.
 spam_sleep: 2
 # The prefix for all commands
 # It has to be prefixed with ! in matrix to be recognised
 command_prefix: "rss"
+# Default post notification template for new subscriptions
+notification_template: "New post in $feed_title: [$title]($link)"
 # Users who can bypass room permission checks
 admins:
 - "@user:example.com"

maubot.yaml

@@ -1,6 +1,6 @@
-maubot: 0.1.0
+maubot: 0.3.0
 id: xyz.maubot.rss
-version: 0.2.3
+version: 0.4.1
 license: AGPL-3.0-or-later
 modules:
 - rss
@@ -10,3 +10,4 @@ extra_files:
 dependencies:
 - feedparser>=5.1
 database: true
+database_type: asyncpg

pyproject.toml

@@ -0,0 +1,11 @@
+[tool.isort]
+profile = "black"
+force_to_top = "typing"
+from_first = true
+combine_as_imports = true
+known_first_party = ["mautrix", "maubot"]
+line_length = 99
+
+[tool.black]
+line-length = 99
+target-version = ["py310"]

rss/bot.py

@@ -1,5 +1,5 @@
 # rss - A maubot plugin to subscribe to RSS/Atom feeds.
-# Copyright (C) 2020 Tulir Asokan
+# Copyright (C) 2022 Tulir Asokan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
@@ -13,30 +13,47 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from typing import Type, List, Any, Dict, Tuple, Awaitable, Iterable, Optional
+from __future__ import annotations
+
+from typing import Any, Iterable
 from datetime import datetime
-from time import mktime, time
 from string import Template
+from time import mktime, time
 import asyncio
+import hashlib
+import html
+import io
 
 import aiohttp
-import hashlib
+import attr
 import feedparser
 
-from mautrix.util.config import BaseProxyConfig, ConfigUpdateHelper
-from mautrix.types import (StateEvent, EventType, MessageType, RoomID, EventID,
-                           PowerLevelStateEventContent)
-from maubot import Plugin, MessageEvent
+from maubot import MessageEvent, Plugin, __version__ as maubot_version
 from maubot.handlers import command, event
+from mautrix.types import (
+    EventID,
+    EventType,
+    MessageType,
+    PowerLevelStateEventContent,
+    RoomID,
+    StateEvent,
+)
+from mautrix.util.async_db import UpgradeTable
+from mautrix.util.config import BaseProxyConfig, ConfigUpdateHelper
 
-from .db import Database, Feed, Entry, Subscription
+from .db import DBManager, Entry, Feed, Subscription
+from .migrations import upgrade_table
+
+rss_change_level = EventType.find("xyz.maubot.rss", t_class=EventType.Class.STATE)
 
 
 class Config(BaseProxyConfig):
     def do_update(self, helper: ConfigUpdateHelper) -> None:
         helper.copy("update_interval")
+        helper.copy("max_backoff")
         helper.copy("spam_sleep")
         helper.copy("command_prefix")
+        helper.copy("notification_template")
         helper.copy("admins")
 
 
@@ -44,7 +61,7 @@ class BoolArgument(command.Argument):
     def __init__(self, name: str, label: str = None, *, required: bool = False) -> None:
         super().__init__(name, label, required=required, pass_raw=False)
 
-    def match(self, val: str, **kwargs) -> Tuple[str, Any]:
+    def match(self, val: str, **kwargs) -> tuple[str, Any]:
         part = val.split(" ")[0].lower()
         if part in ("f", "false", "n", "no", "0"):
             res = False
@@ -52,26 +69,30 @@ class BoolArgument(command.Argument):
             res = True
         else:
             raise ValueError("invalid boolean")
-        return val[len(part):], res
+        return val[len(part) :], res
 
 
 class RSSBot(Plugin):
-    db: Database
+    dbm: DBManager
     poll_task: asyncio.Future
     http: aiohttp.ClientSession
-    power_level_cache: Dict[RoomID, Tuple[int, PowerLevelStateEventContent]]
+    power_level_cache: dict[RoomID, tuple[int, PowerLevelStateEventContent]]
 
     @classmethod
-    def get_config_class(cls) -> Type[BaseProxyConfig]:
+    def get_config_class(cls) -> type[BaseProxyConfig]:
         return Config
 
+    @classmethod
+    def get_db_upgrade_table(cls) -> UpgradeTable:
+        return upgrade_table
+
     async def start(self) -> None:
         await super().start()
         self.config.load_and_update()
-        self.db = Database(self.database)
+        self.dbm = DBManager(self.database)
         self.http = self.client.api.session
         self.power_level_cache = {}
-        self.poll_task = asyncio.ensure_future(self.poll_feeds(), loop=self.loop)
+        self.poll_task = asyncio.create_task(self.poll_feeds())
 
     async def stop(self) -> None:
         await super().stop()
@@ -85,43 +106,77 @@ class RSSBot(Plugin):
         except Exception:
             self.log.exception("Fatal error while polling feeds")
 
-    def _send(self, feed: Feed, entry: Entry, sub: Subscription) -> Awaitable[EventID]:
-        return self.client.send_markdown(sub.room_id, sub.notification_template.safe_substitute({
-            "feed_url": feed.url,
-            "feed_title": feed.title,
-            "feed_subtitle": feed.subtitle,
-            "feed_link": feed.link,
-            **entry._asdict(),
-        }), msgtype=MessageType.NOTICE if sub.send_notice else MessageType.TEXT, allow_html=True)
+    async def _send(self, feed: Feed, entry: Entry, sub: Subscription) -> EventID:
+        message = sub.notification_template.safe_substitute(
+            {
+                "feed_url": feed.url,
+                "feed_title": feed.title,
+                "feed_subtitle": feed.subtitle,
+                "feed_link": feed.link,
+                **attr.asdict(entry),
+            }
+        )
+        msgtype = MessageType.NOTICE if sub.send_notice else MessageType.TEXT
+        try:
+            return await self.client.send_markdown(
+                sub.room_id, message, msgtype=msgtype, allow_html=True
+            )
+        except Exception as e:
+            self.log.warning(f"Failed to send {entry.id} of {feed.id} to {sub.room_id}: {e}")
 
-    async def _broadcast(self, feed: Feed, entry: Entry, subscriptions: List[Subscription]) -> None:
+    async def _broadcast(
+        self, feed: Feed, entry: Entry, subscriptions: list[Subscription]
+    ) -> None:
+        self.log.debug(f"Broadcasting {entry.id} of {feed.id}")
         spam_sleep = self.config["spam_sleep"]
         tasks = [self._send(feed, entry, sub) for sub in subscriptions]
         if spam_sleep >= 0:
             for task in tasks:
                 await task
-                await asyncio.sleep(spam_sleep, loop=self.loop)
+                await asyncio.sleep(spam_sleep)
         else:
             await asyncio.gather(*tasks)
 
     async def _poll_once(self) -> None:
-        subs = self.db.get_feeds()
+        subs = await self.dbm.get_feeds()
         if not subs:
             return
-        for res in asyncio.as_completed([self.try_parse_feed(feed=feed) for feed in subs]):
+        now = int(time())
+        tasks = [self.try_parse_feed(feed=feed) for feed in subs if feed.next_retry < now]
+        feed: Feed
+        entries: Iterable[Entry]
+        self.log.info(f"Polling {len(tasks)} feeds")
+        for res in asyncio.as_completed(tasks):
             feed, entries = await res
+            self.log.trace(
+                f"Fetching {feed.id} (backoff: {feed.error_count} / {feed.next_retry}) "
+                f"success: {bool(entries)}"
+            )
             if not entries:
+                error_count = feed.error_count + 1
+                next_retry_delay = self.config["update_interval"] * 60 * error_count
+                next_retry_delay = min(next_retry_delay, self.config["max_backoff"] * 60)
+                next_retry = int(time() + next_retry_delay)
+                self.log.debug(f"Setting backoff of {feed.id} to {error_count} / {next_retry}")
+                await self.dbm.set_backoff(feed, error_count, next_retry)
                 continue
+            elif feed.error_count > 0:
+                self.log.debug(f"Resetting backoff of {feed.id}")
+                await self.dbm.set_backoff(feed, error_count=0, next_retry=0)
             try:
                 new_entries = {entry.id: entry for entry in entries}
             except Exception:
-                self.log.exception(f"Error items of {feed.url}")
+                self.log.exception(f"Weird error in items of {feed.url}")
                 continue
-            for old_entry in self.db.get_entries(feed.id):
+            for old_entry in await self.dbm.get_entries(feed.id):
                 new_entries.pop(old_entry.id, None)
-            self.db.add_entries(new_entries.values())
-            for entry in new_entries.values():
+            self.log.trace(f"Feed {feed.id} had {len(new_entries)} new entries")
+            new_entry_list: list[Entry] = list(new_entries.values())
+            new_entry_list.sort(key=lambda entry: (entry.date, entry.id))
+            await self.dbm.add_entries(new_entry_list)
+            for entry in new_entry_list:
                 await self._broadcast(feed, entry, feed.subscriptions)
+        self.log.info(f"Finished polling {len(tasks)} feeds")
 
     async def _poll_feeds(self) -> None:
         self.log.debug("Polling started")
@@ -132,24 +187,35 @@ class RSSBot(Plugin):
                 self.log.debug("Polling stopped")
             except Exception:
                 self.log.exception("Error while polling feeds")
-            await asyncio.sleep(self.config["update_interval"] * 60, loop=self.loop)
+            await asyncio.sleep(self.config["update_interval"] * 60)
 
-    async def try_parse_feed(self, feed: Optional[Feed] = None) -> Tuple[Feed, Iterable[Entry]]:
+    async def try_parse_feed(self, feed: Feed | None = None) -> tuple[Feed, list[Entry]]:
         try:
+            self.log.trace(
+                f"Trying to fetch {feed.id} / {feed.url} "
+                f"(backoff: {feed.error_count} / {feed.next_retry})"
+            )
             return await self.parse_feed(feed=feed)
-        except Exception:
-            self.log.exception(f"Failed to parse feed {feed.id} / {feed.url}")
+        except Exception as e:
+            self.log.warning(f"Failed to parse feed {feed.id} / {feed.url}: {e}")
             return feed, []
 
-    async def parse_feed(self, *, feed: Optional[Feed] = None, url: Optional[str] = None
-                         ) -> Tuple[Feed, Iterable[Entry]]:
+    @property
+    def _feed_get_headers(self) -> dict[str, str]:
+        return {
+            "User-Agent": f"maubot/{maubot_version} +https://github.com/maubot/rss",
+        }
+
+    async def parse_feed(
+        self, *, feed: Feed | None = None, url: str | None = None
+    ) -> tuple[Feed, list[Entry]]:
         if feed is None:
             if url is None:
                 raise ValueError("Either feed or url must be set")
-            feed = Feed(-1, url, "", "", "", [])
+            feed = Feed(id=-1, url=url, title="", subtitle="", link="")
         elif url is not None:
             raise ValueError("Only one of feed or url must be set")
-        resp = await self.http.get(feed.url)
+        resp = await self.http.get(feed.url, headers=self._feed_get_headers)
         ct = resp.headers["Content-Type"].split(";")[0].strip()
         if ct == "application/json" or ct == "application/feed+json":
             return await self._parse_json(feed, resp)
@@ -157,67 +223,71 @@ class RSSBot(Plugin):
             return await self._parse_rss(feed, resp)
 
     @classmethod
-    async def _parse_json(cls, feed: Feed, resp: aiohttp.ClientResponse
-                          ) -> Tuple[Feed, Iterable[Entry]]:
+    async def _parse_json(
+        cls, feed: Feed, resp: aiohttp.ClientResponse
+    ) -> tuple[Feed, list[Entry]]:
         content = await resp.json()
-        if content["version"] not in ("https://jsonfeed.org/version/1",
-                                      "https://jsonfeed.org/version/1.1"):
+        if content["version"] not in (
+            "https://jsonfeed.org/version/1",
+            "https://jsonfeed.org/version/1.1",
+        ):
             raise ValueError("Unsupported JSON feed version")
         if not isinstance(content["items"], list):
             raise ValueError("Feed is not a valid JSON feed (items is not a list)")
-        feed = Feed(id=feed.id, title=content["title"], subtitle=content.get("subtitle", ""),
-                    url=feed.url, link=content.get("home_page_url", ""),
-                    subscriptions=feed.subscriptions)
-        return feed, (cls._parse_json_entry(feed.id, entry) for entry in content["items"])
+        feed.title = content["title"]
+        feed.subtitle = content.get("subtitle", "")
+        feed.link = content.get("home_page_url", "")
+        return feed, [cls._parse_json_entry(feed.id, entry) for entry in content["items"]]
 
     @classmethod
-    def _parse_json_entry(cls, feed_id: int, entry: Dict[str, Any]) -> Entry:
+    def _parse_json_entry(cls, feed_id: int, entry: dict[str, Any]) -> Entry:
         try:
             date = datetime.fromisoformat(entry["date_published"])
         except (ValueError, KeyError):
             date = datetime.now()
         title = entry.get("title", "")
-        summary = (entry.get("summary")
-                   or entry.get("content_html")
-                   or entry.get("content_text")
-                   or "")
+        summary = (
+            entry.get("summary") or entry.get("content_html") or entry.get("content_text") or ""
+        ).strip()
         id = str(entry["id"])
         link = entry.get("url") or id
         return Entry(feed_id=feed_id, id=id, date=date, title=title, summary=summary, link=link)
 
     @classmethod
-    async def _parse_rss(cls, feed: Feed, resp: aiohttp.ClientResponse
-                         ) -> Tuple[Feed, Iterable[Entry]]:
-        try:
-            content = await resp.text()
-        except UnicodeDecodeError:
-            try:
-                content = await resp.text(encoding="utf-8", errors="ignore")
-            except UnicodeDecodeError:
-                content = str(await resp.read())[2:-1]
+    async def _parse_rss(
+        cls, feed: Feed, resp: aiohttp.ClientResponse
+    ) -> tuple[Feed, list[Entry]]:
+        content = await resp.read()
         headers = {"Content-Location": feed.url, **resp.headers, "Content-Encoding": "identity"}
-        parsed_data = feedparser.parse(content, response_headers=headers)
+        parsed_data = feedparser.parse(io.BytesIO(content), response_headers=headers)
         if parsed_data.bozo:
             if not isinstance(parsed_data.bozo_exception, feedparser.ThingsNobodyCaresAboutButMe):
                 raise parsed_data.bozo_exception
         feed_data = parsed_data.get("feed", {})
-        feed = Feed(id=feed.id, url=feed.url, title=feed_data.get("title", feed.url),
-                    subtitle=feed_data.get("description", ""), link=feed_data.get("link", ""),
-                    subscriptions=feed.subscriptions)
-        return feed, (cls._parse_rss_entry(feed.id, entry) for entry in parsed_data.entries)
+        feed.title = feed_data.get("title", feed.url)
+        feed.subtitle = feed_data.get("description", "")
+        feed.link = feed_data.get("link", "")
+        return feed, [cls._parse_rss_entry(feed.id, entry) for entry in parsed_data.entries]
 
     @classmethod
     def _parse_rss_entry(cls, feed_id: int, entry: Any) -> Entry:
         return Entry(
             feed_id=feed_id,
-            id=(getattr(entry, "id", None) or
-                hashlib.sha1(" ".join([getattr(entry, "title", ""),
-                                       getattr(entry, "description", ""),
-                                       getattr(entry, "link", "")]).encode("utf-8")
-                             ).hexdigest()),
+            id=(
+                getattr(entry, "id", None)
+                or getattr(entry, "link", None)
+                or hashlib.sha1(
+                    " ".join(
+                        [
+                            getattr(entry, "title", ""),
+                            getattr(entry, "description", ""),
+                        ]
+                    ).encode("utf-8")
+                ).hexdigest()
+            ),
             date=cls._parse_rss_date(entry),
             title=getattr(entry, "title", ""),
-            summary=getattr(entry, "description", ""),
+            summary=getattr(entry, "description", "").strip(),
             link=getattr(entry, "link", ""),
         )
 
@@ -249,97 +319,156 @@ class RSSBot(Plugin):
             return True
         levels = await self.get_power_levels(evt.room_id)
         user_level = levels.get_user_level(evt.sender)
-        state_level = levels.events.get("xyz.maubot.rss", levels.state_default)
-        if type(state_level) != int:
+        state_level = levels.get_event_level(rss_change_level)
+        if not isinstance(state_level, int):
             state_level = 50
         if user_level < state_level:
-            await evt.reply("You don't have the permission to "
-                            "manage the subscriptions of this room.")
+            await evt.reply(
+                "You don't have the permission to manage the subscriptions of this room."
+            )
             return False
         return True
 
-    @command.new(name=lambda self: self.config["command_prefix"],
-                 help="Manage this RSS bot", require_subcommand=True)
+    @command.new(
+        name=lambda self: self.config["command_prefix"],
+        help="Manage this RSS bot",
+        require_subcommand=True,
+    )
     async def rss(self) -> None:
         pass
 
-    @rss.subcommand("subscribe", aliases=("s", "sub"),
-                    help="Subscribe this room to a feed.")
+    @rss.subcommand("subscribe", aliases=("s", "sub"), help="Subscribe this room to a feed.")
     @command.argument("url", "feed URL", pass_raw=True)
     async def subscribe(self, evt: MessageEvent, url: str) -> None:
         if not await self.can_manage(evt):
             return
-        feed = self.db.get_feed_by_url(url)
+        feed = await self.dbm.get_feed_by_url(url)
         if not feed:
             try:
                 info, entries = await self.parse_feed(url=url)
             except Exception as e:
                 await evt.reply(f"Failed to load feed: {e}")
                 return
-            feed = self.db.create_feed(info)
-            self.db.add_entries(entries, override_feed_id=feed.id)
-        self.db.subscribe(feed.id, evt.room_id, evt.sender)
-        await evt.reply(f"Subscribed to feed ID {feed.id}: [{feed.title}]({feed.url})")
+            feed = await self.dbm.create_feed(info)
+            await self.dbm.add_entries(entries, override_feed_id=feed.id)
+        elif feed.error_count > 0:
+            await self.dbm.set_backoff(feed, error_count=feed.error_count, next_retry=0)
+        feed_info = f"feed ID {feed.id}: [{feed.title}]({feed.url})"
+        sub, _ = await self.dbm.get_subscription(feed.id, evt.room_id)
+        if sub is not None:
+            subscriber = (
+                "You"
+                if sub.user_id == evt.sender
+                else f"[{sub.user_id}](https://matrix.to/#/{sub.user_id})"
+            )
+            await evt.reply(f"{subscriber} had already subscribed this room to {feed_info}")
+        else:
+            await self.dbm.subscribe(
+                feed.id, evt.room_id, evt.sender, self.config["notification_template"]
+            )
+            await evt.reply(f"Subscribed to {feed_info}")
 
-    @rss.subcommand("unsubscribe", aliases=("u", "unsub"),
-                    help="Unsubscribe this room from a feed.")
+    @rss.subcommand(
+        "unsubscribe", aliases=("u", "unsub"), help="Unsubscribe this room from a feed."
+    )
     @command.argument("feed_id", "feed ID", parser=int)
     async def unsubscribe(self, evt: MessageEvent, feed_id: int) -> None:
         if not await self.can_manage(evt):
             return
-        sub, feed = self.db.get_subscription(feed_id, evt.room_id)
+        sub, feed = await self.dbm.get_subscription(feed_id, evt.room_id)
         if not sub:
             await evt.reply("This room is not subscribed to that feed")
             return
-        self.db.unsubscribe(feed.id, evt.room_id)
+        await self.dbm.unsubscribe(feed.id, evt.room_id)
         await evt.reply(f"Unsubscribed from feed ID {feed.id}: [{feed.title}]({feed.url})")
 
-    @rss.subcommand("template", aliases=("t", "tpl"),
-                    help="Change the notification template for a subscription in this room")
+    @rss.subcommand(
+        "template",
+        aliases=("t", "tpl"),
+        help="Change the notification template for a subscription in this room",
+    )
     @command.argument("feed_id", "feed ID", parser=int)
-    @command.argument("template", "new template", pass_raw=True)
+    @command.argument("template", "new template", pass_raw=True, required=False)
     async def command_template(self, evt: MessageEvent, feed_id: int, template: str) -> None:
         if not await self.can_manage(evt):
             return
-        sub, feed = self.db.get_subscription(feed_id, evt.room_id)
+        sub, feed = await self.dbm.get_subscription(feed_id, evt.room_id)
         if not sub:
             await evt.reply("This room is not subscribed to that feed")
             return
-        self.db.update_template(feed.id, evt.room_id, template)
-        sub = Subscription(feed_id=feed.id, room_id=sub.room_id, user_id=sub.user_id,
-                           notification_template=Template(template), send_notice=sub.send_notice)
-        sample_entry = Entry(feed.id, "SAMPLE", datetime.now(), "Sample entry",
-                             "This is a sample entry to demonstrate your new template",
-                             "http://example.com")
+        if not template:
+            await evt.reply(
+                '<p>Current template in this room:</p><pre><code language="markdown">'
+                f"{html.escape(sub.notification_template.template)}"
+                "</code></pre>",
+                allow_html=True,
+                markdown=False,
+            )
+            return
+        await self.dbm.update_template(feed.id, evt.room_id, template)
+        sub = Subscription(
+            feed_id=feed.id,
+            room_id=sub.room_id,
+            user_id=sub.user_id,
+            notification_template=Template(template),
+            send_notice=sub.send_notice,
+        )
+        sample_entry = Entry(
+            feed_id=feed.id,
+            id="SAMPLE",
+            date=datetime.now(),
+            title="Sample entry",
+            summary="This is a sample entry to demonstrate your new template",
+            link="http://example.com",
+        )
         await evt.reply(f"Template for feed ID {feed.id} updated. Sample notification:")
         await self._send(feed, sample_entry, sub)
 
-    @rss.subcommand("notice", aliases=("n",),
-                    help="Set whether or not the bot should send updates as m.notice")
+    @rss.subcommand(
+        "notice", aliases=("n",), help="Set whether or not the bot should send updates as m.notice"
+    )
     @command.argument("feed_id", "feed ID", parser=int)
     @BoolArgument("setting", "true/false")
     async def command_notice(self, evt: MessageEvent, feed_id: int, setting: bool) -> None:
         if not await self.can_manage(evt):
             return
-        sub, feed = self.db.get_subscription(feed_id, evt.room_id)
+        sub, feed = await self.dbm.get_subscription(feed_id, evt.room_id)
         if not sub:
             await evt.reply("This room is not subscribed to that feed")
             return
-        self.db.set_send_notice(feed.id, evt.room_id, setting)
+        await self.dbm.set_send_notice(feed.id, evt.room_id, setting)
         send_type = "m.notice" if setting else "m.text"
         await evt.reply(f"Updates for feed ID {feed.id} will now be sent as `{send_type}`")
 
-    @rss.subcommand("subscriptions", aliases=("ls", "list", "subs"),
-                    help="List the subscriptions in the current room.")
+    @staticmethod
+    def _format_subscription(feed: Feed, subscriber: str) -> str:
+        msg = (
+            f"* {feed.id} - [{feed.title}]({feed.url}) "
+            f"(subscribed by [{subscriber}](https://matrix.to/#/{subscriber}))"
+        )
+        if feed.error_count > 1:
+            msg += f"  \n  ⚠️ The last {feed.error_count} attempts to fetch the feed have failed!"
+        return msg
+
+    @rss.subcommand(
+        "subscriptions",
+        aliases=("ls", "list", "subs"),
+        help="List the subscriptions in the current room.",
+    )
     async def command_subscriptions(self, evt: MessageEvent) -> None:
-        subscriptions = self.db.get_feeds_by_room(evt.room_id)
-        await evt.reply("**Subscriptions in this room:**\n\n"
-                        + "\n".join(f"* {feed.id} - [{feed.title}]({feed.url}) (subscribed by "
-                                    f"[{subscriber}](https://matrix.to/#/{subscriber}))"
-                                    for feed, subscriber in subscriptions))
+        subscriptions = await self.dbm.get_feeds_by_room(evt.room_id)
+        if len(subscriptions) == 0:
+            await evt.reply("There are no RSS subscriptions in this room")
+            return
+        await evt.reply(
+            "**Subscriptions in this room:**\n\n"
+            + "\n".join(
+                self._format_subscription(feed, subscriber) for feed, subscriber in subscriptions
+            )
+        )
 
     @event.on(EventType.ROOM_TOMBSTONE)
     async def tombstone(self, evt: StateEvent) -> None:
         if not evt.content.replacement_room:
             return
-        self.db.update_room_id(evt.room_id, evt.content.replacement_room)
+        await self.dbm.update_room_id(evt.room_id, evt.content.replacement_room)

rss/db.py

@@ -1,5 +1,5 @@
 # rss - A maubot plugin to subscribe to RSS/Atom feeds.
-# Copyright (C) 2020 Tulir Asokan
+# Copyright (C) 2022 Tulir Asokan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
@@ -13,205 +13,228 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from typing import Iterable, NamedTuple, List, Optional, Dict, Tuple
+from __future__ import annotations
+
 from datetime import datetime
 from string import Template
 
-from sqlalchemy import (Column, String, Integer, DateTime, Text, Boolean, ForeignKey,
-                        Table, MetaData,
-                        select, and_, true)
-from sqlalchemy.engine.base import Engine
+from asyncpg import Record
+from attr import dataclass
+import attr
 
-from mautrix.types import UserID, RoomID
+from mautrix.types import RoomID, UserID
+from mautrix.util.async_db import Database, Scheme
 
-Subscription = NamedTuple("Subscription", feed_id=int, room_id=RoomID, user_id=UserID,
-                          notification_template=Template, send_notice=bool)
-Feed = NamedTuple("Feed", id=int, url=str, title=str, subtitle=str, link=str,
-                  subscriptions=List[Subscription])
-Entry = NamedTuple("Entry", feed_id=int, id=str, date=datetime, title=str, summary=str, link=str)
+# TODO make this import unconditional after updating mautrix-python
+try:
+    from mautrix.util.async_db import SQLiteCursor
+except ImportError:
+    SQLiteCursor = None
 
 
-class Database:
-    db: Engine
-    feed: Table
-    subscription: Table
-    entry: Table
-    version: Table
+@dataclass
+class Subscription:
+    feed_id: int
+    room_id: RoomID
+    user_id: UserID
+    notification_template: Template
+    send_notice: bool
 
-    def __init__(self, db: Engine) -> None:
+    @classmethod
+    def from_row(cls, row: Record | None) -> Subscription | None:
+        if not row:
+            return None
+        feed_id = row["id"]
+        room_id = row["room_id"]
+        user_id = row["user_id"]
+        if not room_id or not user_id:
+            return None
+        send_notice = bool(row["send_notice"])
+        tpl = Template(row["notification_template"])
+        return cls(
+            feed_id=feed_id,
+            room_id=room_id,
+            user_id=user_id,
+            notification_template=tpl,
+            send_notice=send_notice,
+        )
+
+
+@dataclass
+class Feed:
+    id: int
+    url: str
+    title: str
+    subtitle: str
+    link: str
+
+    next_retry: int = 0
+    error_count: int = 0
+
+    subscriptions: list[Subscription] = attr.ib(factory=lambda: [])
+
+    @classmethod
+    def from_row(cls, row: Record | None) -> Feed | None:
+        if not row:
+            return None
+        data = {**row}
+        data.pop("room_id", None)
+        data.pop("user_id", None)
+        data.pop("send_notice", None)
+        data.pop("notification_template", None)
+        return cls(**data, subscriptions=[])
+
+
+date_fmt = "%Y-%m-%d %H:%M:%S"
+date_fmt_microseconds = "%Y-%m-%d %H:%M:%S.%f"
+
+
+@dataclass
+class Entry:
+    feed_id: int
+    id: str
+    date: datetime
+    title: str
+    summary: str
+    link: str
+
+    @classmethod
+    def from_row(cls, row: Record | None) -> Entry | None:
+        if not row:
+            return None
+        data = {**row}
+        date = data.pop("date")
+        if not isinstance(date, datetime):
+            try:
+                date = datetime.strptime(date, date_fmt_microseconds if "." in date else date_fmt)
+            except ValueError:
+                date = datetime.now()
+        return cls(**data, date=date)
+
+
+class DBManager:
+    db: Database
+
+    def __init__(self, db: Database) -> None:
         self.db = db
-        metadata = MetaData()
-        self.feed = Table("feed", metadata,
-                          Column("id", Integer, primary_key=True, autoincrement=True),
-                          Column("url", Text, nullable=False, unique=True),
-                          Column("title", Text, nullable=False),
-                          Column("subtitle", Text, nullable=False),
-                          Column("link", Text, nullable=False))
-        self.subscription = Table("subscription", metadata,
-                                  Column("feed_id", Integer, ForeignKey("feed.id"),
-                                         primary_key=True),
-                                  Column("room_id", String(255), primary_key=True),
-                                  Column("user_id", String(255), nullable=False),
-                                  Column("notification_template", String(255), nullable=True),
-                                  Column("send_notice", Boolean, nullable=False,
-                                         server_default=true()))
-        self.entry = Table("entry", metadata,
-                           Column("feed_id", Integer, ForeignKey("feed.id"), primary_key=True),
-                           Column("id", String(255), primary_key=True),
-                           Column("date", DateTime, nullable=False),
-                           Column("title", Text, nullable=False),
-                           Column("summary", Text, nullable=False),
-                           Column("link", Text, nullable=False))
-        self.version = Table("version", metadata,
-                             Column("version", Integer, primary_key=True))
-        self.upgrade()
 
-    def upgrade(self) -> None:
-        self.db.execute("CREATE TABLE IF NOT EXISTS version (version INTEGER PRIMARY KEY)")
-        try:
-            version, = next(self.db.execute(select([self.version.c.version])))
-        except (StopIteration, IndexError):
-            version = 0
-        if version == 0:
-            self.db.execute("""CREATE TABLE IF NOT EXISTS feed (
-                id INTEGER NOT NULL,
-                url TEXT NOT NULL,
-                title TEXT NOT NULL,
-                subtitle TEXT NOT NULL,
-                link TEXT NOT NULL,
-                PRIMARY KEY (id),
-                UNIQUE (url)
-            )""")
-            self.db.execute("""CREATE TABLE IF NOT EXISTS subscription (
-                feed_id INTEGER NOT NULL,
-                room_id VARCHAR(255) NOT NULL,
-                user_id VARCHAR(255) NOT NULL,
-                notification_template VARCHAR(255),
-                PRIMARY KEY (feed_id, room_id),
-                FOREIGN KEY(feed_id) REFERENCES feed (id)
-            )""")
-            self.db.execute("""CREATE TABLE IF NOT EXISTS entry (
-                feed_id INTEGER NOT NULL,
-                id VARCHAR(255) NOT NULL,
-                date DATETIME NOT NULL,
-                title TEXT NOT NULL,
-                summary TEXT NOT NULL,
-                link TEXT NOT NULL,
-                PRIMARY KEY (feed_id, id),
-                FOREIGN KEY(feed_id) REFERENCES feed (id)
-            )""")
-            version = 1
-        if version == 1:
-            self.db.execute("ALTER TABLE subscription ADD COLUMN send_notice BOOLEAN DEFAULT true")
-            version = 2
-        self.db.execute(self.version.delete())
-        self.db.execute(self.version.insert().values(version=version))
-
-    def get_feeds(self) -> Iterable[Feed]:
-        rows = self.db.execute(select([self.feed,
-                                       self.subscription.c.room_id,
-                                       self.subscription.c.user_id,
-                                       self.subscription.c.notification_template,
-                                       self.subscription.c.send_notice])
-                               .where(self.subscription.c.feed_id == self.feed.c.id))
-        map: Dict[int, Feed] = {}
+    async def get_feeds(self) -> list[Feed]:
+        q = """
+        SELECT id, url, title, subtitle, link, next_retry, error_count,
+               room_id, user_id, notification_template, send_notice
+        FROM feed INNER JOIN subscription ON feed.id = subscription.feed_id
+        """
+        rows = await self.db.fetch(q)
+        feeds: dict[int, Feed] = {}
         for row in rows:
-            (feed_id, url, title, subtitle, link,
-             room_id, user_id, notification_template, send_notice) = row
-            map.setdefault(feed_id, Feed(feed_id, url, title, subtitle, link, subscriptions=[]))
-            map[feed_id].subscriptions.append(
-                Subscription(feed_id=feed_id, room_id=room_id, user_id=user_id,
-                             notification_template=Template(notification_template),
-                             send_notice=send_notice))
-        return map.values()
+            try:
+                feed = feeds[row["id"]]
+            except KeyError:
+                feed = feeds[row["id"]] = Feed.from_row(row)
+            feed.subscriptions.append(Subscription.from_row(row))
+        return list(feeds.values())
 
-    def get_feeds_by_room(self, room_id: RoomID) -> Iterable[Tuple[Feed, UserID]]:
-        return ((Feed(feed_id, url, title, subtitle, link, subscriptions=[]), user_id)
-                for (feed_id, url, title, subtitle, link, user_id) in
-                self.db.execute(select([self.feed, self.subscription.c.user_id])
-                                .where(and_(self.subscription.c.room_id == room_id,
-                                            self.subscription.c.feed_id == self.feed.c.id))))
+    async def get_feeds_by_room(self, room_id: RoomID) -> list[tuple[Feed, UserID]]:
+        q = """
+        SELECT id, url, title, subtitle, link, next_retry, error_count, user_id FROM feed
+        INNER JOIN subscription ON feed.id = subscription.feed_id AND subscription.room_id = $1
+        """
+        rows = await self.db.fetch(q, room_id)
+        return [(Feed.from_row(row), row["user_id"]) for row in rows]
 
-    def get_rooms_by_feed(self, feed_id: int) -> Iterable[RoomID]:
-        return (row[0] for row in
-                self.db.execute(select([self.subscription.c.room_id])
-                                .where(self.subscription.c.feed_id == feed_id)))
+    async def get_entries(self, feed_id: int) -> list[Entry]:
+        q = "SELECT feed_id, id, date, title, summary, link FROM entry WHERE feed_id = $1"
+        return [Entry.from_row(row) for row in await self.db.fetch(q, feed_id)]
 
-    def get_entries(self, feed_id: int) -> Iterable[Entry]:
-        return (Entry(*row) for row in
-                self.db.execute(select([self.entry]).where(self.entry.c.feed_id == feed_id)))
-
-    def add_entries(self, entries: Iterable[Entry], override_feed_id: Optional[int] = None) -> None:
+    async def add_entries(self, entries: list[Entry], override_feed_id: int | None = None) -> None:
         if not entries:
             return
-        entries = [entry._asdict() for entry in entries]
-        if override_feed_id is not None:
+        if override_feed_id:
             for entry in entries:
-                entry["feed_id"] = override_feed_id
-        self.db.execute(self.entry.insert(), entries)
+                entry.feed_id = override_feed_id
+        records = [attr.astuple(entry) for entry in entries]
+        columns = ("feed_id", "id", "date", "title", "summary", "link")
+        async with self.db.acquire() as conn:
+            if self.db.scheme == Scheme.POSTGRES:
+                await conn.copy_records_to_table("entry", records=records, columns=columns)
+            else:
+                q = (
+                    "INSERT INTO entry (feed_id, id, date, title, summary, link) "
+                    "VALUES ($1, $2, $3, $4, $5, $6)"
+                )
+                await conn.executemany(q, records)
 
-    def get_feed_by_url(self, url: str) -> Optional[Feed]:
-        rows = self.db.execute(select([self.feed]).where(self.feed.c.url == url))
-        try:
-            row = next(rows)
-            return Feed(*row, subscriptions=[])
-        except (ValueError, StopIteration):
-            return None
+    async def get_feed_by_url(self, url: str) -> Feed | None:
+        q = "SELECT id, url, title, subtitle, link, next_retry, error_count FROM feed WHERE url=$1"
+        return Feed.from_row(await self.db.fetchrow(q, url))
 
-    def get_feed_by_id(self, feed_id: int) -> Optional[Feed]:
-        rows = self.db.execute(select([self.feed]).where(self.feed.c.id == feed_id))
-        try:
-            row = next(rows)
-            return Feed(*row, subscriptions=[])
-        except (ValueError, StopIteration):
-            return None
+    async def get_subscription(
+        self, feed_id: int, room_id: RoomID
+    ) -> tuple[Subscription | None, Feed | None]:
+        q = """
+        SELECT id, url, title, subtitle, link, next_retry, error_count,
+               room_id, user_id, notification_template, send_notice
+        FROM feed LEFT JOIN subscription ON feed.id = subscription.feed_id AND room_id = $2
+        WHERE feed.id = $1
+        """
+        row = await self.db.fetchrow(q, feed_id, room_id)
+        return Subscription.from_row(row), Feed.from_row(row)
 
-    def get_subscription(self, feed_id: int, room_id: RoomID) -> Tuple[Optional[Subscription],
-                                                                       Optional[Feed]]:
-        tbl = self.subscription
-        rows = self.db.execute(select([self.feed, tbl.c.room_id, tbl.c.user_id,
-                                       tbl.c.notification_template, tbl.c.send_notice])
-                               .where(and_(tbl.c.feed_id == feed_id, tbl.c.room_id == room_id,
-                                           self.feed.c.id == feed_id)))
-        try:
-            (feed_id, url, title, subtitle, link,
-             room_id, user_id, template, send_notice) = next(rows)
-            notification_template = Template(template)
-            return (Subscription(feed_id, room_id, user_id, notification_template, send_notice)
-                    if room_id else None,
-                    Feed(feed_id, url, title, subtitle, link, []))
-        except (ValueError, StopIteration):
-            return None, None
+    async def update_room_id(self, old: RoomID, new: RoomID) -> None:
+        await self.db.execute("UPDATE subscription SET room_id = $1 WHERE room_id = $2", new, old)
 
-    def update_room_id(self, old: RoomID, new: RoomID) -> None:
-        self.db.execute(self.subscription.update()
-                        .where(self.subscription.c.room_id == old)
-                        .values(room_id=new))
+    async def create_feed(self, info: Feed) -> Feed:
+        q = (
+            "INSERT INTO feed (url, title, subtitle, link, next_retry) "
+            "VALUES ($1, $2, $3, $4, $5) RETURNING (id)"
+        )
+        # SQLite only gained RETURNING support in v3.35 (2021-03-12)
+        # TODO remove this special case in a couple of years
+        if self.db.scheme == Scheme.SQLITE:
+            cur = await self.db.execute(
+                q.replace(" RETURNING (id)", ""),
+                info.url,
+                info.title,
+                info.subtitle,
+                info.link,
+                info.next_retry,
+            )
+            if SQLiteCursor is not None:
+                assert isinstance(cur, SQLiteCursor)
+            info.id = cur.lastrowid
+        else:
+            info.id = await self.db.fetchval(
+                q, info.url, info.title, info.subtitle, info.link, info.next_retry
+            )
+        return info
 
-    def create_feed(self, info: Feed) -> Feed:
-        res = self.db.execute(self.feed.insert().values(url=info.url, title=info.title,
-                                                        subtitle=info.subtitle, link=info.link))
-        return Feed(id=res.inserted_primary_key[0], url=info.url, title=info.title,
-                    subtitle=info.subtitle, link=info.link, subscriptions=[])
+    async def set_backoff(self, info: Feed, error_count: int, next_retry: int) -> None:
+        q = "UPDATE feed SET error_count = $2, next_retry = $3 WHERE id = $1"
+        await self.db.execute(q, info.id, error_count, next_retry)
 
-    def subscribe(self, feed_id: int, room_id: RoomID, user_id: UserID) -> None:
-        self.db.execute(self.subscription.insert().values(
-            feed_id=feed_id, room_id=room_id, user_id=user_id,
-            notification_template="New post in $feed_title: [$title]($link)"))
+    async def subscribe(
+        self,
+        feed_id: int,
+        room_id: RoomID,
+        user_id: UserID,
+        template: str | None = None,
+        send_notice: bool = True,
+    ) -> None:
+        q = """
+        INSERT INTO subscription (feed_id, room_id, user_id, notification_template, send_notice)
+        VALUES ($1, $2, $3, $4, $5)
+        """
+        template = template or "New post in $feed_title: [$title]($link)"
+        await self.db.execute(q, feed_id, room_id, user_id, template, send_notice)
 
-    def unsubscribe(self, feed_id: int, room_id: RoomID) -> None:
-        tbl = self.subscription
-        self.db.execute(tbl.delete().where(and_(tbl.c.feed_id == feed_id,
-                                                tbl.c.room_id == room_id)))
+    async def unsubscribe(self, feed_id: int, room_id: RoomID) -> None:
+        q = "DELETE FROM subscription WHERE feed_id = $1 AND room_id = $2"
+        await self.db.execute(q, feed_id, room_id)
 
-    def update_template(self, feed_id: int, room_id: RoomID, template: str) -> None:
-        tbl = self.subscription
-        self.db.execute(tbl.update()
-                        .where(and_(tbl.c.feed_id == feed_id, tbl.c.room_id == room_id))
-                        .values(notification_template=template))
+    async def update_template(self, feed_id: int, room_id: RoomID, template: str) -> None:
+        q = "UPDATE subscription SET notification_template=$3 WHERE feed_id=$1 AND room_id=$2"
+        await self.db.execute(q, feed_id, room_id, template)
 
-    def set_send_notice(self, feed_id: int, room_id: RoomID, send_notice: bool) -> None:
-        tbl = self.subscription
-        self.db.execute(tbl.update()
-                        .where(and_(tbl.c.feed_id == feed_id, tbl.c.room_id == room_id))
-                        .values(send_notice=send_notice))
+    async def set_send_notice(self, feed_id: int, room_id: RoomID, send_notice: bool) -> None:
+        q = "UPDATE subscription SET send_notice=$3 WHERE feed_id=$1 AND room_id=$2"
+        await self.db.execute(q, feed_id, room_id, send_notice)

rss/migrations.py

@@ -1,5 +1,5 @@
 # rss - A maubot plugin to subscribe to RSS/Atom feeds.
-# Copyright (C) 2019 Tulir Asokan
+# Copyright (C) 2022 Tulir Asokan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
@@ -13,13 +13,62 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from sqlalchemy import select
-from sqlalchemy.engine.base import Engine
-from alembic.migration import MigrationContext
-from alembic.operations import Operations
+from mautrix.util.async_db import Connection, Scheme, UpgradeTable
+
+upgrade_table = UpgradeTable()
 
 
-def run(engine: Engine):
-    conn = engine.connect()
-    ctx = MigrationContext.configure(conn)
-    op = Operations(ctx)
+@upgrade_table.register(description="Latest revision", upgrades_to=3)
+async def upgrade_latest(conn: Connection, scheme: Scheme) -> None:
+    gen = "GENERATED ALWAYS AS IDENTITY" if scheme != Scheme.SQLITE else ""
+    await conn.execute(
+        f"""CREATE TABLE IF NOT EXISTS feed (
+            id       INTEGER {gen},
+            url      TEXT NOT NULL,
+            title    TEXT NOT NULL,
+            subtitle TEXT NOT NULL,
+            link     TEXT NOT NULL,
+
+            next_retry  BIGINT DEFAULT 0,
+            error_count BIGINT DEFAULT 0,
+
+            PRIMARY KEY (id),
+            UNIQUE (url)
+        )"""
+    )
+    await conn.execute(
+        """CREATE TABLE IF NOT EXISTS subscription (
+            feed_id INTEGER,
+            room_id TEXT,
+            user_id TEXT NOT NULL,
+
+            notification_template TEXT,
+            send_notice           BOOLEAN DEFAULT true,
+
+            PRIMARY KEY (feed_id, room_id),
+            FOREIGN KEY (feed_id) REFERENCES feed (id)
+        )"""
+    )
+    await conn.execute(
+        """CREATE TABLE IF NOT EXISTS entry (
+            feed_id INTEGER,
+            id      TEXT,
+            date    timestamp NOT NULL,
+            title   TEXT NOT NULL,
+            summary TEXT NOT NULL,
+            link    TEXT NOT NULL,
+            PRIMARY KEY (feed_id, id),
+            FOREIGN KEY (feed_id) REFERENCES feed (id)
+        )"""
+    )
+
+
+@upgrade_table.register(description="Add send_notice field to subscriptions")
+async def upgrade_v2(conn: Connection) -> None:
+    await conn.execute("ALTER TABLE subscription ADD COLUMN send_notice BOOLEAN DEFAULT true")
+
+
+@upgrade_table.register(description="Add error counts to feeds")
+async def upgrade_v3(conn: Connection) -> None:
+    await conn.execute("ALTER TABLE feed ADD COLUMN next_retry BIGINT DEFAULT 0")
+    await conn.execute("ALTER TABLE feed ADD COLUMN error_count BIGINT DEFAULT 0")