From df0f7d134d5b07894762d07190b62019bf84a55e Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Sun, 19 Apr 2020 17:32:40 +0300
Subject: [PATCH] Collection items: add a transaction endpoint.

---
 django_etesync/models.py |  4 ++++
 django_etesync/views.py  | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/django_etesync/models.py b/django_etesync/models.py
index c6ec571..05b81b3 100644
--- a/django_etesync/models.py
+++ b/django_etesync/models.py
@@ -71,6 +71,10 @@ class CollectionItem(models.Model):
     def content(self):
         return self.revisions.get(current=True)
 
+    @cached_property
+    def stoken(self):
+        return self.content.uid
+
 
 def chunk_directory_path(instance, filename):
     item = instance.item
diff --git a/django_etesync/views.py b/django_etesync/views.py
index b9cd878..87c8010 100644
--- a/django_etesync/views.py
+++ b/django_etesync/views.py
@@ -14,7 +14,7 @@
 
 from django.conf import settings
 from django.contrib.auth import get_user_model
-from django.db import IntegrityError
+from django.db import transaction, IntegrityError
 from django.db.models import Max
 from django.http import HttpResponseBadRequest, HttpResponse, Http404
 from django.shortcuts import get_object_or_404
@@ -215,6 +215,35 @@ class CollectionItemViewSet(BaseViewSet):
         }
         return Response(ret, headers={'X-EteSync-SToken': new_stoken})
 
+    @action_decorator(detail=False, methods=['POST'])
+    def transaction(self, request, collection_uid=None):
+        collection_object = get_object_or_404(self.get_collection_queryset(Collection.objects), uid=collection_uid)
+
+        items = request.data.get('items')
+        # FIXME: deps should actually be just pairs of uid and stoken
+        deps = request.data.get('deps', None)
+        serializer = self.get_serializer_class()(data=items, context=self.get_serializer_context(), many=True)
+        deps_serializer = self.get_serializer_class()(data=deps, context=self.get_serializer_context(), many=True)
+        if serializer.is_valid() and (deps is None or deps_serializer.is_valid()):
+            try:
+                with transaction.atomic():
+                    collections = serializer.save(collection=collection_object)
+            except IntegrityError:
+                content = {'code': 'integrity_error'}
+                return Response(content, status=status.HTTP_400_BAD_REQUEST)
+
+            ret = {
+                "data": [collection.stoken for collection in collections],
+            }
+            return Response(ret, status=status.HTTP_201_CREATED)
+
+        return Response(
+            {
+                "items": serializer.errors,
+                "deps": deps_serializer.errors if deps is not None else [],
+            },
+            status=status.HTTP_400_BAD_REQUEST)
+
 
 class CollectionItemChunkViewSet(viewsets.ViewSet):
     allowed_methods = ['GET', 'POST']