Push notifications for upcoming volunteer shifts

Author: jellybob

apps/base/__init__.py

@@ -207,4 +207,5 @@ def deliveries():
 from . import tasks_banking  # noqa
 from . import tasks_export  # noqa
 from . import tasks_videos  # noqa
+from ..notifications import tasks  # noqa
 from . import dev  # noqa

apps/notifications/jobs.py

@@ -0,0 +1,103 @@
+from sqlalchemy import and_
+from main import db
+from datetime import datetime, timedelta
+from flask import current_app as app
+
+from models import scheduled_task
+from models.cfp import Proposal
+from models.user import User
+from models.volunteer.shift import Shift, ShiftEntry
+from models.web_push import PushNotificationJob, enqueue_if_not_exists
+from models.notifications import UserNotificationPreference
+from pywebpush import webpush, WebPushException
+
+
+def deliver_notification(job: PushNotificationJob):
+    """Deliver a push notification from a PushNotificationJob.
+
+    The passed job will be mutated to reflect delivery state. A job which isn't
+    queued will be skipped over.
+    """
+    if job.state != "queued":
+        return
+
+    try:
+        webpush(
+            subscription_info=job.target.subscription_info,
+            data=job.title,
+            vapid_private_key=app.config["WEBPUSH_PRIVATE_KEY"],
+            vapid_claims={
+                "sub": "mailto:[email protected]",
+            },
+        )
+
+        job.state = "delivered"
+    except WebPushException as err:
+        job.state = "failed"
+        job.error = err.message
+
+
+@scheduled_task(minutes=1)
+def send_queued_notifications():
+    jobs = PushNotificationJob.query.where(
+        PushNotificationJob.state == "queued"
+        and (PushNotificationJob.not_before is None or PushNotificationJob.not_before <= datetime.now())
+    ).all()
+
+    for job in jobs:
+        deliver_notification(job)
+        db.session.add(job)
+
+    db.session.commit()
+
+
+@scheduled_task(minutes=15)
+def queue_content_notifications(time=None) -> None:
+    if time is None:
+        time = datetime.now()
+
+    users = User.query.join(
+        UserNotificationPreference,
+        User.notification_preferences.and_(UserNotificationPreference.favourited_content),
+    )
+
+    upcoming_content = Proposal.query.filter(
+        and_(Proposal.scheduled_time >= time, Proposal.scheduled_time <= time + timedelta(minutes=16))
+    ).all()
+
+    for user in users:
+        user_favourites = [f.id for f in user.favourites]
+        favourites = [p for p in upcoming_content if p.id in user_favourites]
+        for proposal in favourites:
+            for target in user.web_push_targets:
+                enqueue_if_not_exists(
+                    target=target,
+                    related_to=f"favourite,user:{user.id},proposal:{proposal.id},target:{target.id}",
+                    title=f"{proposal.title} is happening soon at {proposal.scheduled_venue.name}",
+                    not_before=proposal.scheduled_time - timedelta(minutes=15),
+                )
+
+    db.session.commit()
+
+
+@scheduled_task(minutes=15)
+def queue_shift_notifications(time=None) -> None:
+    if time is None:
+        time = datetime.now()
+
+    upcoming_shifts: list[Shift] = Shift.query.filter(
+        and_(Shift.start >= time, Shift.start <= time + timedelta(minutes=16))
+    ).all()
+
+    for shift in upcoming_shifts:
+        for user in shift.volunteers:
+            if user.notification_preferences.volunteer_shifts:
+                for target in user.web_push_targets:
+                    enqueue_if_not_exists(
+                        target=target,
+                        related_to=f"shift_reminder,user:{user.id},shift:{shift.id},target:{target.id}",
+                        title=f"Your {shift.role.name} shift is about to start, please go to {shift.venue.name}.",
+                        not_before=shift.start - timedelta(minutes=15),
+                    )
+
+    db.session.commit()

apps/notifications/tasks.py

@@ -22,6 +22,31 @@ def notify(target, message):
     )
 
 
+def enqueue_if_not_exists(
+    target: "WebPushTarget",
+    title: str,
+    body: str | None = None,
+    related_to: str | None = None,
+    not_before: datetime | None = None,
+) -> "PushNotificationJob":
+    if related_to is not None:
+        existing_job = PushNotificationJob.query.where(
+            PushNotificationJob.related_to == related_to
+        ).one_or_none()
+        if existing_job is not None:
+            return existing_job
+
+    job = PushNotificationJob(
+        target=target,
+        title=title,
+        body=body,
+        related_to=related_to,
+        not_before=not_before,
+    )
+    db.session.add(job)
+    return job
+
+
 class WebPushTarget(BaseModel):
     __table_name__ = "web_push_target"
     id = db.Column(db.Integer, primary_key=True)