implement API to check if user paid for event or not (#280)

src/pretix/api/urls.py

@@ -100,4 +100,5 @@
     url(r"^upload$", upload.UploadView.as_view(), name="upload"),
     url(r"^me$", user.MeView.as_view(), name="user.me"),
     url(r"^version$", version.VersionView.as_view(), name="version"),
+    url(r"(?P<organizer>[^/]+)/(?P<event>[^/]+)/customer/(?P<customer_id>[^/]+)/ticket-check", event.CustomerOrderCheckView.as_view()),
 ]

src/pretix/api/views/event.py

@@ -1,6 +1,7 @@
 import django_filters
 from django.db import transaction
 from django.db.models import ProtectedError, Q
+from django.http import JsonResponse
 from django.utils.timezone import now
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_scopes import scopes_disabled
@@ -15,7 +16,7 @@
 )
 from pretix.api.views import ConditionalListView
 from pretix.base.models import (
-    CartPosition, Device, Event, TaxRule, TeamAPIToken,
+    CartPosition, Device, Event, TaxRule, TeamAPIToken, Organizer, Customer, Order,
 )
 from pretix.base.models.event import SubEvent
 from pretix.base.settings import SETTINGS_AFFECTING_CSS
@@ -402,3 +403,38 @@ def patch(self, request, *wargs, **kwargs):
                 'request': request
             })
         return Response(s.data)
+
+
+class CustomerOrderCheckView(views.View):
+
+    def get(self, request, *args, **kwargs):
+        if (not kwargs.get("customer_id")
+                or not kwargs.get("event")
+                or not kwargs.get("organizer")):
+            return Response(status=400, data={"error": "Missing parameters."})
+
+        try:
+            organizer = Organizer.objects.get(slug=kwargs["organizer"])
+            event = Event.objects.get(slug=kwargs["event"], organizer=organizer)
+            customer = Customer.objects.get(identifier=kwargs["customer_id"], organizer=organizer)
+
+        except Organizer.DoesNotExist:
+            return JsonResponse(status=404, data={"error": "Organizer not found."})
+        except Event.DoesNotExist:
+            return JsonResponse(status=404, data={"error": "Event not found."})
+        except Customer.DoesNotExist:
+            return JsonResponse(status=404, data={"error": "Customer not found."})
+
+        # Get all orders of customer which belong to this event
+        order_list = (Order.objects.filter(Q(event=event)
+                                           & (Q(customer=customer) | Q(
+            email__iexact=customer.email))).select_related('event').order_by('-datetime'))
+
+        if not order_list:
+            return JsonResponse(status=404, data={"error": "Customer has no orders for this event."})
+
+        for order in order_list:
+            if order.status == 'p':
+                return JsonResponse(status=200, data={"message": "Customer has paid orders."})
+
+        return JsonResponse(status=400, data={"message": "Customer did not paid orders."})