Add API endpoint for Quota.availability

doc/api/resources/quotas.rst

@@ -69,7 +69,7 @@ Endpoints
 
 .. http:get:: /api/v1/organizers/(organizer)/events/(event)/quotas/(id)/
 
-   Returns information on one question, identified by its ID.
+   Returns information on one quota, identified by its ID.
 
    **Example request**:
 
@@ -95,6 +95,46 @@ Endpoints
         "variations": [1, 4, 5, 7]
       }
 
+   :param organizer: The ``slug`` field of the organizer to fetch
+   :param event: The ``slug`` field of the event to fetch
+   :param id: The ``id`` field of the quota to fetch
+   :statuscode 200: no error
+         :statuscode 401: Authentication failure
+         :statuscode 403: The requested organizer/event does not exist **or** you have no permission to view this resource.
+
+.. http:get:: /api/v1/organizers/(organizer)/events/(event)/quotas/(id)/availability/
+
+   Returns availability information on one quota, identified by its ID.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      GET /api/v1/organizers/bigevents/events/sampleconf/quotas/1/availability/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: text/javascript
+
+      {
+        "available": true,
+        "available_number": 419,
+        "total_size": 1000,
+        "pending_orders": 25,
+        "paid_orders": 423,
+        "cart_positions": 7,
+        "blocking_vouchers": 126,
+        "waiting_list": 0
+    }
+
+   Note that ``total_size`` and ``available_number`` are ``null`` in case of unlimited quotas.
+
    :param organizer: The ``slug`` field of the organizer to fetch
    :param event: The ``slug`` field of the event to fetch
    :param id: The ``id`` field of the quota to fetch

src/pretix/api/views/item.py

@@ -1,6 +1,8 @@
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from rest_framework import viewsets
+from rest_framework.decorators import detail_route
 from rest_framework.filters import OrderingFilter
+from rest_framework.response import Response
 
 from pretix.api.serializers.item import (
     ItemCategorySerializer, ItemSerializer, QuestionSerializer,
@@ -65,3 +67,21 @@ class QuotaViewSet(viewsets.ReadOnlyModelViewSet):
 
     def get_queryset(self):
         return self.request.event.quotas.all()
+
+    @detail_route(methods=['get'])
+    def availability(self, request, *args, **kwargs):
+        quota = self.get_object()
+
+        avail = quota.availability()
+
+        data = {
+            'paid_orders': quota.count_paid_orders(),
+            'pending_orders': quota.count_pending_orders(),
+            'blocking_vouchers': quota.count_blocking_vouchers(),
+            'cart_positions': quota.count_in_cart(),
+            'waiting_list': quota.count_waiting_list_pending(),
+            'available_number': avail[1],
+            'available': avail[0] == Quota.AVAILABILITY_OK,
+            'total_size': quota.size,
+        }
+        return Response(data)

src/tests/api/test_items.py

@@ -219,6 +219,21 @@ def test_quota_detail(token_client, organizer, event, quota, item):
     assert res == resp.data
 
 
+@pytest.mark.django_db
+def test_quota_availability(token_client, organizer, event, quota, item):
+    resp = token_client.get('/api/v1/organizers/{}/events/{}/quotas/{}/availability/'.format(
+        organizer.slug, event.slug, quota.pk))
+    assert resp.status_code == 200
+    assert {'blocking_vouchers': 0,
+            'available_number': 200,
+            'pending_orders': 0,
+            'cart_positions': 0,
+            'available': True,
+            'total_size': 200,
+            'paid_orders': 0,
+            'waiting_list': 0} == resp.data
+
+
 @pytest.fixture
 def question(event, item):
     q = event.questions.create(question="T-Shirt size", type="C")