Lazy-load widgets on global dashboard

src/pretix/control/views/dashboards.py

@@ -352,7 +352,7 @@ def event_index_widgets_lazy(request, organizer, event):
     return JsonResponse({'widgets': widgets})
 
 
-def annotated_event_query(request):
+def annotated_event_query(request, lazy=False):
     active_orders = Order.objects.filter(
         event=OuterRef('pk'),
         status__in=[Order.STATUS_PENDING, Order.STATUS_PAID]
@@ -366,10 +366,13 @@ def annotated_event_query(request):
         event=OuterRef('pk'),
         done=False
     )
-    qs = request.user.get_events_with_any_permission(request).annotate(
-        order_count=Subquery(active_orders, output_field=IntegerField()),
-        has_ra=Exists(required_actions)
-    ).annotate(
+    qs = request.user.get_events_with_any_permission(request)
+    if not lazy:
+        qs = qs.annotate(
+            order_count=Subquery(active_orders, output_field=IntegerField()),
+            has_ra=Exists(required_actions)
+        )
+    qs = qs.annotate(
         min_from=Min('subevents__date_from'),
         max_from=Max('subevents__date_from'),
         max_to=Max('subevents__date_to'),
@@ -380,14 +383,15 @@ def annotated_event_query(request):
     return qs
 
 
-def widgets_for_event_qs(request, qs, user, nmax):
+def widgets_for_event_qs(request, qs, user, nmax, lazy=False):
     widgets = []
 
     # Get set of events where we have the permission to show the # of orders
-    events_with_orders = set(qs.filter(
-        Q(organizer_id__in=user.teams.filter(all_events=True, can_view_orders=True).values_list('organizer', flat=True))
-        | Q(id__in=user.teams.filter(can_view_orders=True).values_list('limit_events__id', flat=True))
-    ).values_list('id', flat=True))
+    if not lazy:
+        events_with_orders = set(qs.filter(
+            Q(organizer_id__in=user.teams.filter(all_events=True, can_view_orders=True).values_list('organizer', flat=True))
+            | Q(id__in=user.teams.filter(can_view_orders=True).values_list('limit_events__id', flat=True))
+        ).values_list('id', flat=True))
 
     tpl = """
         <a href="{url}" class="event">
@@ -403,36 +407,40 @@ def widgets_for_event_qs(request, qs, user, nmax):
         </div>
     """
 
-    events = qs.prefetch_related(
-        '_settings_objects', 'organizer___settings_objects'
-    ).select_related('organizer')[:nmax]
+    if lazy:
+        events = qs[:nmax]
+    else:
+        events = qs.prefetch_related(
+            '_settings_objects', 'organizer___settings_objects'
+        ).select_related('organizer')[:nmax]
     for event in events:
-        tzname = event.cache.get_or_set('timezone', lambda: event.settings.timezone)
-        tz = pytz.timezone(tzname)
-        if event.has_subevents:
-            if event.min_from is None:
-                dr = pgettext("subevent", "No dates")
+        if not lazy:
+            tzname = event.cache.get_or_set('timezone', lambda: event.settings.timezone)
+            tz = pytz.timezone(tzname)
+            if event.has_subevents:
+                if event.min_from is None:
+                    dr = pgettext("subevent", "No dates")
+                else:
+                    dr = daterange(
+                        (event.min_from).astimezone(tz),
+                        (event.max_fromto or event.max_to or event.max_from).astimezone(tz)
+                    )
             else:
-                dr = daterange(
-                    (event.min_from).astimezone(tz),
-                    (event.max_fromto or event.max_to or event.max_from).astimezone(tz)
-                )
-        else:
-            if event.date_to:
-                dr = daterange(event.date_from.astimezone(tz), event.date_to.astimezone(tz))
-            else:
-                dr = date_format(event.date_from.astimezone(tz), "DATE_FORMAT")
+                if event.date_to:
+                    dr = daterange(event.date_from.astimezone(tz), event.date_to.astimezone(tz))
+                else:
+                    dr = date_format(event.date_from.astimezone(tz), "DATE_FORMAT")
 
-        if event.has_ra:
-            status = ('danger', _('Action required'))
-        elif not event.live:
-            status = ('warning', _('Shop disabled'))
-        elif event.presale_has_ended:
-            status = ('default', _('Sale over'))
-        elif not event.presale_is_running:
-            status = ('default', _('Soon'))
-        else:
-            status = ('success', _('On sale'))
+            if event.has_ra:
+                status = ('danger', _('Action required'))
+            elif not event.live:
+                status = ('warning', _('Shop disabled'))
+            elif event.presale_has_ended:
+                status = ('default', _('Sale over'))
+            elif not event.presale_is_running:
+                status = ('default', _('Soon'))
+            else:
+                status = ('success', _('On sale'))
 
         widgets.append({
             'content': tpl.format(
@@ -463,8 +471,9 @@ def widgets_for_event_qs(request, qs, user, nmax):
                 daterange=dr,
                 status=status[1],
                 statusclass=status[0],
-            ),
+            ) if not lazy else '',
             'display_size': 'small',
+            'lazy': 'event-{}'.format(event.pk),
             'priority': 100,
             'container_class': 'widget-container widget-container-event',
         })
@@ -482,6 +491,43 @@ def widgets_for_event_qs(request, qs, user, nmax):
     return widgets
 
 
+def user_index_widgets_lazy(request):
+    widgets = []
+    widgets += widgets_for_event_qs(
+        request,
+        annotated_event_query(request).filter(
+            Q(has_subevents=False) &
+            Q(
+                Q(Q(date_to__isnull=True) & Q(date_from__gte=now()))
+                | Q(Q(date_to__isnull=False) & Q(date_to__gte=now()))
+            )
+        ).order_by('date_from'),
+        request.user,
+        7
+    )
+    widgets += widgets_for_event_qs(
+        request,
+        annotated_event_query(request).filter(
+            Q(has_subevents=False) &
+            Q(
+                Q(Q(date_to__isnull=True) & Q(date_from__lt=now()))
+                | Q(Q(date_to__isnull=False) & Q(date_to__lt=now()))
+            )
+        ).order_by('-order_to'),
+        request.user,
+        8
+    )
+    widgets += widgets_for_event_qs(
+        request,
+        annotated_event_query(request).filter(
+            has_subevents=True
+        ).order_by('-order_to'),
+        request.user,
+        8
+    )
+    return JsonResponse({'widgets': widgets})
+
+
 def user_index(request):
     widgets = []
     for r, result in user_dashboard_widgets.send(request, user=request.user):
@@ -491,7 +537,7 @@ def user_index(request):
         'widgets': rearrange(widgets),
         'upcoming': widgets_for_event_qs(
             request,
-            annotated_event_query(request).filter(
+            annotated_event_query(request, lazy=True).filter(
                 Q(has_subevents=False) &
                 Q(
                     Q(Q(date_to__isnull=True) & Q(date_from__gte=now()))
@@ -499,11 +545,12 @@ def user_index(request):
                 )
             ).order_by('date_from'),
             request.user,
-            7
+            7,
+            lazy=True
         ),
         'past': widgets_for_event_qs(
             request,
-            annotated_event_query(request).filter(
+            annotated_event_query(request, lazy=True).filter(
                 Q(has_subevents=False) &
                 Q(
                     Q(Q(date_to__isnull=True) & Q(date_from__lt=now()))
@@ -511,15 +558,17 @@ def user_index(request):
                 )
             ).order_by('-order_to'),
             request.user,
-            8
+            8,
+            lazy=True
         ),
         'series': widgets_for_event_qs(
             request,
-            annotated_event_query(request).filter(
+            annotated_event_query(request, lazy=True).filter(
                 has_subevents=True
             ).order_by('-order_to'),
             request.user,
-            8
+            8,
+            lazy=True
         ),
     }
     return render(request, 'pretixcontrol/dashboard.html', ctx)