Event API: Allow to query availability

src/pretix/api/serializers/event.py

@@ -42,6 +42,7 @@ from django.utils.functional import cached_property
 from django.utils.translation import gettext as _
 from django_countries.serializers import CountryFieldMixin
 from pytz import common_timezones
+from rest_framework import serializers
 from rest_framework.fields import ChoiceField, Field
 from rest_framework.relations import SlugRelatedField
 
@@ -93,9 +94,12 @@ class MetaPropertyField(Field):
 class SeatCategoryMappingField(Field):
 
     def to_representation(self, value):
-        qs = value.seat_category_mappings.all()
-        if isinstance(value, Event):
-            qs = qs.filter(subevent=None)
+        if hasattr(value, '_seat_category_mappings'):
+            qs = value._seat_category_mappings
+        else:
+            qs = value.seat_category_mappings.all()
+            if isinstance(value, Event):
+                qs = qs.filter(subevent=None)
         return {
             v.layout_category: v.product_id for v in qs
         }
@@ -156,6 +160,7 @@ class EventSerializer(I18nAwareModelSerializer):
     seat_category_mapping = SeatCategoryMappingField(source='*', required=False)
     timezone = TimeZoneField(required=False, choices=[(a, a) for a in common_timezones])
     valid_keys = ValidKeysField(source='*', read_only=True)
+    best_availability_state = serializers.IntegerField(allow_null=True, read_only=True)
 
     class Meta:
         model = Event
@@ -163,12 +168,14 @@ class EventSerializer(I18nAwareModelSerializer):
                   'date_to', 'date_admission', 'is_public', 'presale_start',
                   'presale_end', 'location', 'geo_lat', 'geo_lon', 'has_subevents', 'meta_data', 'seating_plan',
                   'plugins', 'seat_category_mapping', 'timezone', 'item_meta_properties', 'valid_keys',
-                  'sales_channels')
+                  'sales_channels', 'best_availability_state')
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         if not hasattr(self.context['request'], 'event'):
             self.fields.pop('valid_keys')
+        if not self.context.get('request') or 'with_availability_for' not in self.context['request'].GET:
+            self.fields.pop('best_availability_state')
 
     def validate(self, data):
         data = super().validate(data)
@@ -441,13 +448,19 @@ class SubEventSerializer(I18nAwareModelSerializer):
     seat_category_mapping = SeatCategoryMappingField(source='*', required=False)
     event = SlugRelatedField(slug_field='slug', read_only=True)
     meta_data = MetaDataField(source='*')
+    best_availability_state = serializers.IntegerField(allow_null=True, read_only=True)
 
     class Meta:
         model = SubEvent
         fields = ('id', 'name', 'date_from', 'date_to', 'active', 'date_admission',
                   'presale_start', 'presale_end', 'location', 'geo_lat', 'geo_lon', 'event', 'is_public',
                   'frontpage_text', 'seating_plan', 'item_price_overrides', 'variation_price_overrides',
-                  'meta_data', 'seat_category_mapping', 'last_modified')
+                  'meta_data', 'seat_category_mapping', 'last_modified', 'best_availability_state')
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if not self.context.get('request') or 'with_availability_for' not in self.context['request'].GET:
+            self.fields.pop('best_availability_state')
 
     def validate(self, data):
         data = super().validate(data)

src/pretix/api/views/event.py

@@ -34,7 +34,7 @@
 
 import django_filters
 from django.db import transaction
-from django.db.models import ProtectedError, Q
+from django.db.models import Prefetch, ProtectedError, Q
 from django.utils.timezone import now
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_scopes import scopes_disabled
@@ -49,9 +49,10 @@ from pretix.api.serializers.event import (
 )
 from pretix.api.views import ConditionalListView
 from pretix.base.models import (
-    CartPosition, Device, Event, TaxRule, TeamAPIToken,
+    CartPosition, Device, Event, SeatCategoryMapping, TaxRule, TeamAPIToken,
 )
 from pretix.base.models.event import SubEvent
+from pretix.base.services.quotas import QuotaAvailability
 from pretix.base.settings import SETTINGS_AFFECTING_CSS
 from pretix.helpers.dicts import merge_dicts
 from pretix.presale.style import regenerate_css
@@ -136,10 +137,43 @@ class EventViewSet(viewsets.ModelViewSet):
             )
 
         qs = filter_qs_by_attr(qs, self.request)
+
+        if 'with_availability_for' in self.request.GET:
+            qs = Event.annotated(qs, channel=self.request.GET.get('with_availability_for'))
+
         return qs.prefetch_related(
-            'meta_values', 'meta_values__property', 'seat_category_mappings'
+            'organizer',
+            'meta_values',
+            'meta_values__property',
+            'item_meta_properties',
+            Prefetch(
+                'seat_category_mappings',
+                to_attr='_seat_category_mappings',
+                queryset=SeatCategoryMapping.objects.filter(subevent=None)
+            ),
         )
 
+    def list(self, request, *args, **kwargs):
+        queryset = self.filter_queryset(self.get_queryset())
+
+        page = self.paginate_queryset(queryset)
+
+        if 'with_availability_for' in self.request.GET:
+            quotas_to_compute = []
+            qcache = {}
+            for se in page:
+                se._quota_cache = qcache
+                quotas_to_compute += se.active_quotas
+
+            if quotas_to_compute:
+                qa = QuotaAvailability()
+                qa.queue(*quotas_to_compute)
+                qa.compute(allow_cache=True)
+                qcache.update(qa.results)
+
+        serializer = self.get_serializer(page, many=True)
+        return self.get_paginated_response(serializer.data)
+
     def perform_update(self, serializer):
         current_live_value = serializer.instance.live
         updated_live_value = serializer.validated_data.get('live', None)
@@ -197,7 +231,6 @@ class EventViewSet(viewsets.ModelViewSet):
             except Event.DoesNotExist:
                 raise ValidationError('Event to copy from was not found')
 
-        print(copy_from, self.request.GET)
         new_event = serializer.save(organizer=self.request.organizer)
 
         if copy_from:
@@ -336,8 +369,18 @@ class SubEventViewSet(ConditionalListView, viewsets.ModelViewSet):
 
         qs = filter_qs_by_attr(qs, self.request)
 
+        if 'with_availability_for' in self.request.GET:
+            qs = SubEvent.annotated(qs, channel=self.request.GET.get('with_availability_for'))
+
         return qs.prefetch_related(
-            'subeventitem_set', 'subeventitemvariation_set', 'seat_category_mappings', 'meta_values'
+            'event',
+            'subeventitem_set',
+            'subeventitemvariation_set',
+            'meta_values',
+            Prefetch(
+                'seat_category_mappings',
+                to_attr='_seat_category_mappings',
+            ),
         )
 
     def list(self, request, **kwargs):
@@ -345,14 +388,24 @@ class SubEventViewSet(ConditionalListView, viewsets.ModelViewSet):
         queryset = self.filter_queryset(self.get_queryset())
 
         page = self.paginate_queryset(queryset)
-        if page is not None:
-            serializer = self.get_serializer(page, many=True)
-            resp = self.get_paginated_response(serializer.data)
-            resp['X-Page-Generated'] = date
-            return resp
 
-        serializer = self.get_serializer(queryset, many=True)
-        return Response(serializer.data, headers={'X-Page-Generated': date})
+        if 'with_availability_for' in self.request.GET:
+            quotas_to_compute = []
+            qcache = {}
+            for se in page:
+                se._quota_cache = qcache
+                quotas_to_compute += se.active_quotas
+
+            if quotas_to_compute:
+                qa = QuotaAvailability()
+                qa.queue(*quotas_to_compute)
+                qa.compute(allow_cache=True)
+                qcache.update(qa.results)
+
+        serializer = self.get_serializer(page, many=True)
+        resp = self.get_paginated_response(serializer.data)
+        resp['X-Page-Generated'] = date
+        return resp
 
     def perform_update(self, serializer):
         original_data = self.get_serializer(instance=serializer.instance).data