Expose personal calendar in iCal format instead of provisioning Google Calendars

hknweb/events/admin/__init__.py

@@ -1,16 +1,14 @@
-from hknweb.events.admin.attendance import (
-    AttendanceFormAdmin,
-    AttendanceResponseAdmin,
-)
+from django.contrib import admin
+
+from hknweb.events.admin.attendance import AttendanceFormAdmin, AttendanceResponseAdmin
+from hknweb.events.admin.event import EventAdmin
+from hknweb.events.admin.event_type import EventTypeAdmin
 from hknweb.events.admin.google_calendar import (
     GCalAccessLevelMappingAdmin,
     GoogleCalendarCredentialsAdmin,
 )
-from hknweb.events.admin.event import EventAdmin
-from hknweb.events.admin.event_type import EventTypeAdmin
+from hknweb.events.admin.ical_view import ICalViewAdmin
 from hknweb.events.admin.rsvp import RsvpAdmin
-
-from django.contrib import admin
 from hknweb.events.models import EventPhoto
 
 admin.site.register(EventPhoto)

hknweb/events/admin/ical_view.py

@@ -0,0 +1,14 @@
+from django.contrib import admin
+
+from hknweb.events.models import ICalView
+
+
+@admin.register(ICalView)
+class ICalViewAdmin(admin.ModelAdmin):
+    fields = ["user", "show_rsvpd", "show_not_rsvpd"]
+    list_display = ["id", "user"]
+    search_fields = [
+        "user__username",
+        "user__first_name",
+        "user__last_name",
+    ]

hknweb/events/migrations/0012_icalview.py

@@ -0,0 +1,39 @@
+# Generated by Django 4.2.5 on 2023-10-05 05:03
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import uuid
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ("events", "0011_eventphoto"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="ICalView",
+            fields=[
+                (
+                    "id",
+                    models.UUIDField(
+                        default=uuid.uuid4,
+                        editable=False,
+                        primary_key=True,
+                        serialize=False,
+                    ),
+                ),
+                ("show_rsvpd", models.BooleanField(default=True)),
+                ("show_not_rsvpd", models.BooleanField(default=False)),
+                (
+                    "user",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+        ),
+    ]

hknweb/events/models/__init__.py

@@ -7,3 +7,4 @@
 )
 from hknweb.events.models.attendance import AttendanceForm, AttendanceResponse
 from hknweb.events.models.event_photo import EventPhoto
+from hknweb.events.models.ical_view import ICalView

hknweb/events/models/event.py

@@ -1,14 +1,14 @@
-from django.db import models
+import icalendar
 from django.contrib.auth.models import User
-
+from django.db import models
+from icalendar import vCalAddress, vText
 from markdownx.models import MarkdownxField
 
-from hknweb.utils import get_semester
 import hknweb.events.google_calendar_utils as gcal
-
+from hknweb.events.models.constants import ACCESS_LEVELS
 from hknweb.events.models.event_type import EventType
 from hknweb.events.models.google_calendar import GCalAccessLevelMapping
-from hknweb.events.models.constants import ACCESS_LEVELS
+from hknweb.utils import get_semester
 
 
 class Event(models.Model):
@@ -41,6 +41,29 @@ def semester(self):
         Example: "Spring 2020" """
         return get_semester(self.start_time)
 
+    def to_ical_obj(self):
+        event = icalendar.Event()
+        event.add("uid", self.id)
+        event.add("summary", self.name)
+        event.add("location", self.location)
+        event.add("description", self.description)
+        event.add("dtstart", self.start_time)
+        event.add("dtend", self.end_time)
+        event.add("dtstamp", self.created_at)
+
+        def make_attendee(user, status):
+            attendee = vCalAddress(f"MAILTO:{user.email}")
+            attendee.params["PARTSTAT"] = vText(status)
+            attendee.params["CN"] = vText(f"{user.first_name} {user.last_name}")
+            return attendee
+
+        for rsvp in self.admitted_set():
+            event.add("attendee", make_attendee(rsvp.user, "ACCEPTED"), encode=0)
+        for rsvp in self.waitlist_set():
+            event.add("attendee", make_attendee(rsvp.user, "TENTATIVE"), encode=0)
+
+        return event
+
     def get_absolute_url(self):
         return "/events/{}".format(self.id)
 

hknweb/events/models/ical_view.py

@@ -0,0 +1,63 @@
+import random
+import uuid
+from datetime import datetime, timedelta
+
+import icalendar
+from django.conf import settings
+from django.db import models
+from django.urls import reverse
+
+from hknweb.events.models import Event
+from hknweb.events.utils import get_events
+
+
+class ICalView(models.Model):
+    class Meta:
+        verbose_name = "iCal view"
+
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
+    show_rsvpd = models.BooleanField(default=True)
+    show_not_rsvpd = models.BooleanField(default=False)
+
+    @property
+    def url(self):
+        return reverse("events:ical", args=[self.id])
+
+    def to_ical_obj(self):
+        cal = icalendar.Calendar()
+        cal.add("prodid", "-//Eta Kappa Nu, Mu Chapter//Calendar//EN")
+        cal.add("version", "2.0")
+        cal.add("summary", f"HKN Personal Calendar for {self.user}")
+
+        events = get_events(self.user, self.show_rsvpd, self.show_not_rsvpd)
+        for event in events:
+            cal.add_component(event.to_ical_obj())
+
+        cal.add_component(self.dummy_event())
+        return cal
+
+    def dummy_event(self):
+        # Google Calendar doesn't let you configure how often to sync iCal feeds
+        # like Apple's Calendar app does. They say this can take up to 24 hours.
+
+        # According to https://webapps.stackexchange.com/a/66686, they probably
+        # look at how often the iCal feed itself changes and syncs more or less
+        # frequently based on that.
+
+        # So we add a dummy event in the far future that's randomized every time
+        # the feed is requested in hopes of making Google Calendar sync faster.
+
+        dt = datetime(3000, 1, 1) + timedelta(days=random.randrange(365))
+
+        event = icalendar.Event()
+        event.add("uid", "dummy")
+        event.add("summary", "Dummy Event")
+        event.add(
+            "description",
+            "Randomized dummy event to make Google Calendar sync faster",
+        )
+        event.add("dtstart", dt)
+        event.add("dtend", dt)
+        event.add("dtstamp", dt)
+        return event

hknweb/events/models/rsvp.py

@@ -1,9 +1,9 @@
-from django.db import models
 from django.contrib.auth.models import User
+from django.db import models
 
-from hknweb.models import Profile
-from hknweb.events.models.event import Event
 import hknweb.events.google_calendar_utils as gcal
+from hknweb.events.models.event import Event
+from hknweb.models import Profile
 
 
 class Rsvp(models.Model):
@@ -30,8 +30,10 @@ def has_not_rsvpd(cls, user, event):
     def save(self, *args, **kwargs):
         profile = Profile.objects.filter(user=self.user).first()
         if not profile.google_calendar_id:
-            profile.google_calendar_id = gcal.create_personal_calendar()
-            profile.save()
+            # we no longer provision new personal google calendars
+            # instead, we generate a ICalView and a route to view it
+            # so they can add it to any calendar app
+            return super().save(*args, **kwargs)
 
         if self.google_calendar_event_id is None:
             self.google_calendar_event_id = gcal.create_event(

hknweb/events/urls.py

@@ -1,11 +1,12 @@
 from django.urls import path
-import hknweb.events.views as views
 
+import hknweb.events.views as views
 
 app_name = "events"
 
 aggregate_display_urls = [
     path("", views.index, name="index"),
+    path("ical/<uuid:id>.ics", views.ical, name="ical"),
     path("leaderboard", views.get_leaderboard, name="leaderboard"),
     path("photos", views.photos, name="photos"),
 ]

hknweb/events/utils.py

@@ -7,6 +7,37 @@
 
 from hknweb.events.constants import ATTR
 from hknweb.events.models import Event
+from hknweb.utils import get_access_level
+
+
+def get_events(user, show_rsvpd, show_not_rsvpd):
+    """Retrieves the events a user can see.
+
+    Parameters
+    ----------
+    user: django.contrib.auth.models.User
+        The user authenticating the request (can be anonymous)
+    show_rsvpd: bool
+        Whether to include events the user has RSVP'd for
+    show_not_rsvpd: bool
+        Whether to include events the user has not RSVP'd for
+
+    Returns
+    -------
+    QuerySet of Event objects
+    """
+
+    events = Event.objects.order_by("-start_time").filter(
+        access_level__gte=get_access_level(user)
+    )
+
+    if user.is_authenticated:
+        if not show_rsvpd:
+            events = events.exclude(rsvp__user=user)
+        if not show_not_rsvpd:
+            events = events.filter(rsvp__user=user)
+
+    return events
 
 
 def create_event(data, start_time, end_time, user):

hknweb/events/views/__init__.py

@@ -1,5 +1,6 @@
 from hknweb.events.views.aggregate_displays import (
     index,
+    ical,
     get_leaderboard,
     photos,
 )

hknweb/events/views/aggregate_displays/__init__.py

@@ -1,3 +1,3 @@
-from hknweb.events.views.aggregate_displays.calendar import index
+from hknweb.events.views.aggregate_displays.calendar import ical, index
 from hknweb.events.views.aggregate_displays.leaderboard import get_leaderboard
 from hknweb.events.views.aggregate_displays.photos import photos

hknweb/events/views/aggregate_displays/calendar.py

@@ -1,12 +1,15 @@
+import uuid
 from typing import List
 
-from django.shortcuts import render
+from django.http import HttpResponse
+from django.shortcuts import get_object_or_404, render
 
-from hknweb.models import Profile
-from hknweb.events.models import Event, EventType, GCalAccessLevelMapping
+from hknweb.events.google_calendar_utils import SHARE_LINK_TEMPLATE, get_calendar_link
+from hknweb.events.models import Event, EventType, GCalAccessLevelMapping, ICalView
 from hknweb.events.models.constants import ACCESS_LEVELS
+from hknweb.events.utils import get_events
+from hknweb.models import Profile
 from hknweb.utils import allow_public_access, get_access_level
-from hknweb.events.google_calendar_utils import get_calendar_link
 
 
 @allow_public_access
@@ -28,6 +31,12 @@ def index(request):
     )
 
 
+@allow_public_access
+def ical(request, *, id: uuid.UUID):
+    ical_view = get_object_or_404(ICalView, pk=id)
+    return HttpResponse(ical_view.to_ical_obj().to_ical(), content_type="text/calendar")
+
+
 def calendar_helper(
     request,
     title,
@@ -37,15 +46,7 @@ def calendar_helper(
     show_sidebar=False,
 ):
     user_access_level = get_access_level(request.user)
-
-    events = Event.objects.order_by("-start_time").filter(
-        access_level__gte=user_access_level
-    )
-    if request.user.is_authenticated:
-        if not rsvpd_display:
-            events = events.exclude(rsvp__user=request.user)
-        if not not_rsvpd_display:
-            events = events.filter(rsvp__user=request.user)
+    events = get_events(request.user, rsvpd_display, not_rsvpd_display)
 
     all_event_types = event_types = EventType.objects.order_by("type")
     if event_type_types:
@@ -85,11 +86,21 @@ def get_calendars(request, user_access_level: int):
         if profile.google_calendar_id:
             calendars.append(
                 {
-                    "name": "personal",
+                    "name": "personal (gcal)",
                     "link": get_calendar_link(calendar_id=profile.google_calendar_id),
                 }
             )
 
+        ical_view, _ = ICalView.objects.get_or_create(user=request.user)
+        ical_url = request.build_absolute_uri(ical_view.url)
+        ical_url = ical_url.replace("https://", "webcal://")
+        calendars.append(
+            {
+                "name": "personal (ics)",
+                "link": SHARE_LINK_TEMPLATE.format(cid=ical_url),
+            }
+        )
+
     for calendar in calendars[:-1]:
         calendar["separator"] = "/"
     if len(calendars) > 0:

hknweb/settings/prod.py

@@ -25,3 +25,6 @@
 # https://docs.djangoproject.com/en/2.1/howto/static-files/
 STATIC_URL = "https://www.ocf.berkeley.edu/~hkn/hknweb/static/"
 STATIC_ROOT = "/home/h/hk/hkn/public_html/hknweb/static/"
+
+USE_X_FORWARDED_HOST = True
+SECURE_PROXY_SSL_HEADER = ("HTTP_X_FORWARDED_PROTO", "https")