add apprise and send notification when refreshing listings

crawler/notifications.py

@@ -0,0 +1,27 @@
+from abc import abstractmethod
+from enum import StrEnum
+import apprise
+from functools import lru_cache
+
+
+class Surface:
+    @abstractmethod
+    def connection_string(self) -> str | None:
+        ...
+
+class Slack(Surface):
+    def connection_string(self) -> str | None:
+        return "https://hooks.slack.com/services/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"
+
+
+@lru_cache(maxsize=None)
+def get_notifier(surfaces: list[Surface] | None = None) -> apprise.Apprise:
+    surfaces = surfaces or [Slack()]
+    obj = apprise.Apprise()
+    for surface in surfaces:
+        obj.add(surface.connection_string())
+    return obj
+
+async def send_notification( body: str, title: str='') -> bool:
+    notifier = get_notifier()
+    return await notifier.async_notify(body=body, title=title)