Reusable media (#3131)

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

src/pretix/api/views/media.py

@@ -0,0 +1,160 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from decimal import Decimal
+
+import django_filters
+from django.db import transaction
+from django.db.models import OuterRef, Prefetch, Subquery, Sum
+from django.db.models.functions import Coalesce
+from django.utils.timezone import now
+from django_filters.rest_framework import DjangoFilterBackend, FilterSet
+from django_scopes import scopes_disabled
+from rest_framework import viewsets, serializers
+from rest_framework.decorators import action
+from rest_framework.exceptions import MethodNotAllowed
+from rest_framework.filters import OrderingFilter
+from rest_framework.response import Response
+
+from pretix.api.serializers.media import (
+    MediaLookupInputSerializer, ReusableMediaSerializer,
+)
+from pretix.base.media import MEDIA_TYPES
+from pretix.base.models import (
+    Checkin, GiftCard, GiftCardTransaction, OrderPosition, ReusableMedium,
+)
+from pretix.helpers import OF_SELF
+from pretix.helpers.dicts import merge_dicts
+
+with scopes_disabled():
+    class ReusableMediumFilter(FilterSet):
+        identifier = django_filters.CharFilter(field_name='identifier')
+        type = django_filters.CharFilter(field_name='type')
+        customer = django_filters.CharFilter(field_name='customer__identifier')
+        updated_since = django_filters.IsoDateTimeFilter(field_name='updated', lookup_expr='gte')
+        created_since = django_filters.IsoDateTimeFilter(field_name='created', lookup_expr='gte')
+
+        class Meta:
+            model = ReusableMedium
+            fields = ['identifier', 'type', 'active', 'customer', 'linked_orderposition', 'linked_giftcard']
+
+
+class ReusableMediaViewSet(viewsets.ModelViewSet):
+    serializer_class = ReusableMediaSerializer
+    queryset = ReusableMedium.objects.none()
+    permission = 'can_manage_reusable_media'
+    write_permission = 'can_manage_reusable_media'
+    filter_backends = (DjangoFilterBackend, OrderingFilter)
+    ordering = ('-updated', '-id')
+    ordering_fields = ('created', 'updated', 'identifier', 'type', 'id')
+    filterset_class = ReusableMediumFilter
+
+    def get_queryset(self):
+        s = GiftCardTransaction.objects.filter(
+            card=OuterRef('pk')
+        ).order_by().values('card').annotate(s=Sum('value')).values('s')
+        return self.request.organizer.reusable_media.prefetch_related(
+            Prefetch(
+                'linked_orderposition',
+                queryset=OrderPosition.objects.select_related(
+                    'order', 'order__event', 'order__event__organizer', 'seat',
+                ).prefetch_related(
+                    Prefetch('checkins', queryset=Checkin.objects.all()),
+                    'answers', 'answers__options', 'answers__question',
+                )
+            ),
+            Prefetch(
+                'linked_giftcard',
+                queryset=GiftCard.objects.annotate(
+                    cached_value=Coalesce(Subquery(s), Decimal('0.00'))
+                )
+            )
+        )
+
+    def get_serializer_context(self):
+        ctx = super().get_serializer_context()
+        ctx['organizer'] = self.request.organizer
+        return ctx
+
+    @transaction.atomic()
+    def perform_create(self, serializer):
+        inst = serializer.save(organizer=self.request.organizer)
+        inst.log_action(
+            'pretix.reusable_medium.created',
+            user=self.request.user,
+            auth=self.request.auth,
+            data=merge_dicts(self.request.data, {'id': inst.pk})
+        )
+
+    @transaction.atomic()
+    def perform_update(self, serializer):
+        ReusableMedium.objects.select_for_update(of=OF_SELF).get(pk=self.get_object().pk)
+        inst = serializer.save(identifier=serializer.instance.identifier, type=serializer.instance.type)
+        inst.log_action(
+            'pretix.reusable_medium.changed',
+            user=self.request.user,
+            auth=self.request.auth,
+            data=self.request.data,
+        )
+        return inst
+
+    def perform_destroy(self, instance):
+        raise MethodNotAllowed("Media cannot be deleted.")
+
+    @action(methods=["POST"], detail=False)
+    def lookup(self, request, *args, **kwargs):
+        s = MediaLookupInputSerializer(
+            data=request.data,
+        )
+        s.is_valid(raise_exception=True)
+
+        try:
+            m = ReusableMedium.objects.get(
+                type=s.validated_data["type"],
+                identifier=s.validated_data["identifier"],
+                organizer=request.organizer,
+            )
+            s = self.get_serializer(m)
+            return Response({"result": s.data})
+        except ReusableMedium.DoesNotExist:
+            mt = MEDIA_TYPES.get(s.validated_data["type"])
+            if mt:
+                m = mt.handle_unknown(request.organizer, s.validated_data["identifier"], request.user, request.auth)
+                if m:
+                    s = self.get_serializer(m)
+                    return Response({"result": s.data})
+
+            return Response({"result": None})
+
+    @scopes_disabled()  # we are sure enough that get_queryset() is correct, so we save some perforamnce
+    def list(self, request, **kwargs):
+        date = serializers.DateTimeField().to_representation(now())
+        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})