Allow to customize description of calendar files (#2415)

Co-authored-by: Martin Gross <gross@rami.io>

src/pretix/presale/ical.py

@@ -28,11 +28,16 @@ from django.conf import settings
 from django.utils.formats import date_format
 from django.utils.translation import gettext as _
 
+from pretix.base.email import get_email_context
 from pretix.base.models import Event
 from pretix.multidomain.urlreverse import build_absolute_uri
 
 
-def get_ical(events):
+def get_public_ical(events):
+    """
+    Return an ical feed for a sequence of events or subevents. The calendar files will only include public
+    information.
+    """
     cal = vobject.iCalendar()
     cal.add('prodid').value = '-//pretix//{}//'.format(settings.PRETIX_INSTANCE_NAME.replace(" ", "_"))
     creation_time = datetime.datetime.now(pytz.utc)
@@ -83,3 +88,91 @@ def get_ical(events):
 
         vevent.add('description').value = '\n'.join(descr)
     return cal
+
+
+def get_private_icals(event, positions):
+    """
+    Return a list of ical objects based on a sequence of positions.
+
+    Unlike get_public_ical, this will
+
+    - Generate multiple ical files instead of one (but with deduplication applied)
+    - Respect the mail_attach_ical_description setting
+
+    It is private in the sense that mail_attach_ical_description may contain content not suited for
+    public display.
+
+    We however intentionally do not allow using placeholders based on the order and position
+    specifically. This is for two reasons:
+
+    - In reality, many people will add their invite to their calendar which is shared with a larger
+      team. People are probably not aware that they're sharing sensitive information such as their
+      secret ticket link with everyone they share their calendar with.
+
+    - It would be pretty hard to implement it in a way that doesn't require us to use distinct
+      settings fields for emails to customers and to attendees, which feels like an overcomplication.
+    """
+
+    from pretix.base.services.mail import TolerantDict
+
+    tz = pytz.timezone(event.settings.timezone)
+
+    creation_time = datetime.datetime.now(pytz.utc)
+    calobjects = []
+
+    evs = set(p.subevent or event for p in positions)
+    for ev in evs:
+        if isinstance(ev, Event):
+            url = build_absolute_uri(event, 'presale:event.index')
+        else:
+            url = build_absolute_uri(event, 'presale:event.index', {
+                'subevent': ev.pk
+            })
+
+        if event.settings.mail_attach_ical_description:
+            ctx = get_email_context(event=event, event_or_subevent=ev)
+            description = str(event.settings.mail_attach_ical_description).format_map(TolerantDict(ctx))
+        else:
+            # Default description
+            descr = []
+            descr.append(_('Tickets: {url}').format(url=url))
+            if ev.date_admission:
+                descr.append(str(_('Admission: {datetime}')).format(
+                    datetime=date_format(ev.date_admission.astimezone(tz), 'SHORT_DATETIME_FORMAT')
+                ))
+
+            descr.append(_('Organizer: {organizer}').format(organizer=event.organizer.name))
+            description = '\n'.join(descr)
+
+        cal = vobject.iCalendar()
+        cal.add('prodid').value = '-//pretix//{}//'.format(settings.PRETIX_INSTANCE_NAME.replace(" ", "_"))
+
+        vevent = cal.add('vevent')
+        vevent.add('summary').value = str(ev.name)
+        vevent.add('description').value = description
+        vevent.add('dtstamp').value = creation_time
+        if ev.location:
+            vevent.add('location').value = str(ev.location)
+
+        vevent.add('uid').value = 'pretix-{}-{}-{}@{}'.format(
+            event.organizer.slug,
+            event.organizer.slug, event.slug,
+            ev.pk if not isinstance(ev, Event) else '0',
+            urlparse(url).netloc
+        )
+
+        if event.settings.show_times:
+            vevent.add('dtstart').value = ev.date_from.astimezone(tz)
+        else:
+            vevent.add('dtstart').value = ev.date_from.astimezone(tz).date()
+
+        if event.settings.show_date_to and ev.date_to:
+            if event.settings.show_times:
+                vevent.add('dtend').value = ev.date_to.astimezone(tz)
+            else:
+                # with full-day events date_to in pretix is included (e.g. last day)
+                # whereas dtend in vcalendar is non-inclusive => add one day for export
+                vevent.add('dtend').value = ev.date_to.astimezone(tz).date() + datetime.timedelta(days=1)
+
+        calobjects.append(cal)
+    return calobjects