Refs #314 -- Read-only REST API (#513)

* initial commit

* API auth

* Hierarchical URLs

* Add session auth

* Strong hierarchy

* Add filters

* Add i18n fields, questions

* More viewsets and serializers

* Ticket download

* Add OrderPosition serializer

* View-level permissions

* More tests

* More tests

* Add basic API docs

* Add REST API to docs frontpage

* Tests for order endpoints

* Add invoice tests

* Voucher and waitinglist tests

* Doc draft

* order docs

* Docs on all viewsets

* Disable DRF docs, style sphinx, style browsable API

* Fix tests

* deprecated imports

* Test foo

* Attendee names

* Fix migration problems

* Remove browsable API, plugin integration

* Doc fixes

src/pretix/api/views/item.py

@@ -0,0 +1,67 @@
+from django_filters.rest_framework import DjangoFilterBackend, FilterSet
+from rest_framework import viewsets
+from rest_framework.filters import OrderingFilter
+
+from pretix.api.serializers.item import (
+    ItemCategorySerializer, ItemSerializer, QuestionSerializer,
+    QuotaSerializer,
+)
+from pretix.base.models import Item, ItemCategory, Question, Quota
+
+
+class ItemFilter(FilterSet):
+    class Meta:
+        model = Item
+        fields = ['active', 'category', 'admission', 'tax_rate', 'free_price']
+
+
+class ItemViewSet(viewsets.ReadOnlyModelViewSet):
+    serializer_class = ItemSerializer
+    queryset = Item.objects.none()
+    filter_backends = (DjangoFilterBackend, OrderingFilter)
+    ordering_fields = ('id', 'position')
+    ordering = ('position', 'id')
+    filter_class = ItemFilter
+
+    def get_queryset(self):
+        return self.request.event.items.prefetch_related('variations', 'addons').all()
+
+
+class ItemCategoryFilter(FilterSet):
+    class Meta:
+        model = ItemCategory
+        fields = ['is_addon']
+
+
+class ItemCategoryViewSet(viewsets.ReadOnlyModelViewSet):
+    serializer_class = ItemCategorySerializer
+    queryset = ItemCategory.objects.none()
+    filter_backends = (DjangoFilterBackend, OrderingFilter)
+    filter_class = ItemCategoryFilter
+    ordering_fields = ('id', 'position')
+    ordering = ('position', 'id')
+
+    def get_queryset(self):
+        return self.request.event.categories.all()
+
+
+class QuestionViewSet(viewsets.ReadOnlyModelViewSet):
+    serializer_class = QuestionSerializer
+    queryset = Question.objects.none()
+    filter_backends = (OrderingFilter,)
+    ordering_fields = ('id', 'position')
+    ordering = ('position', 'id')
+
+    def get_queryset(self):
+        return self.request.event.questions.prefetch_related('options').all()
+
+
+class QuotaViewSet(viewsets.ReadOnlyModelViewSet):
+    serializer_class = QuotaSerializer
+    queryset = Quota.objects.none()
+    filter_backends = (OrderingFilter,)
+    ordering_fields = ('id', 'size')
+    ordering = ('id',)
+
+    def get_queryset(self):
+        return self.request.event.quotas.all()