Collection: also save the collection UID on the model itself.

This enables us to have db-constraints for making sure that UIDs are
unique, as well as being more efficient for lookups (which are very
common).

The UID should always be the same as the main_item.uid, though that's
easily enforced as neither of them is allowed to change.

django_etebase/migrations/0033_collection_uid.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.1.1 on 2020-12-14 11:21
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_etebase', '0032_auto_20201013_1409'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='collection',
+            name='uid',
+            field=models.CharField(db_index=True, max_length=43, null=True, validators=[django.core.validators.RegexValidator(message='Not a valid UID', regex='^[a-zA-Z0-9\\-_]{20,}$')]),
+        ),
+    ]

django_etebase/migrations/0034_auto_20201214_1124.py

@@ -0,0 +1,22 @@
+# Generated by Django 3.1.1 on 2020-12-14 11:24
+
+from django.db import migrations
+
+
+def update_collection_uid(apps, schema_editor):
+    Collection = apps.get_model("django_etebase", "Collection")
+
+    for collection in Collection.objects.all():
+        collection.uid = collection.main_item.uid
+        collection.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("django_etebase", "0033_collection_uid"),
+    ]
+
+    operations = [
+        migrations.RunPython(update_collection_uid),
+    ]

django_etebase/migrations/0035_auto_20201214_1126.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.1.1 on 2020-12-14 11:26
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_etebase', '0034_auto_20201214_1124'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='collection',
+            name='uid',
+            field=models.CharField(db_index=True, max_length=43, validators=[django.core.validators.RegexValidator(message='Not a valid UID', regex='^[a-zA-Z0-9\\-_]{20,}$')]),
+        ),
+    ]

django_etebase/migrations/0036_auto_20201214_1128.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.1.1 on 2020-12-14 11:28
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_etebase', '0035_auto_20201214_1126'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='collection',
+            name='uid',
+            field=models.CharField(db_index=True, max_length=43, unique=True, validators=[django.core.validators.RegexValidator(message='Not a valid UID', regex='^[a-zA-Z0-9\\-_]{20,}$')]),
+        ),
+    ]

django_etebase/models.py

@@ -43,6 +43,8 @@ class CollectionType(models.Model):
 
 class Collection(models.Model):
     main_item = models.OneToOneField("CollectionItem", related_name="parent", null=True, on_delete=models.SET_NULL)
+    # The same as main_item.uid, we just also save it here so we have DB constraints for uniqueness (and efficiency)
+    uid = models.CharField(db_index=True, unique=True, blank=False, max_length=43, validators=[UidValidator])
     owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
 
     stoken_annotation = stoken_annotation_builder(["items__revisions__stoken", "members__stoken"])
@@ -50,10 +52,6 @@ class Collection(models.Model):
     def __str__(self):
         return self.uid
 
-    @cached_property
-    def uid(self):
-        return self.main_item.uid
-
     @property
     def content(self):
         return self.main_item.content
@@ -76,20 +74,6 @@ class Collection(models.Model):
 
         return Stoken.objects.get(id=stoken_id).uid
 
-    def validate_unique(self, exclude=None):
-        super().validate_unique(exclude=exclude)
-        if exclude is None or "main_item" in exclude:
-            return
-
-        if (
-            self.__class__.objects.filter(owner=self.owner, main_item__uid=self.main_item.uid)
-            .exclude(id=self.id)
-            .exists()
-        ):
-            raise EtebaseValidationError(
-                "unique_uid", "Collection with this uid already exists", status_code=status.HTTP_409_CONFLICT
-            )
-
 
 class CollectionItem(models.Model):
     uid = models.CharField(db_index=True, blank=False, max_length=43, validators=[UidValidator])

django_etebase/serializers.py

@@ -313,13 +313,13 @@ class CollectionSerializer(BetterErrorsMixin, serializers.ModelSerializer):
 
         user = validated_data.get("owner")
         main_item_data = validated_data.pop("main_item")
+        uid = main_item_data.get("uid")
         etag = main_item_data.pop("etag")
         revision_data = main_item_data.pop("content")
 
-        instance = self.__class__.Meta.model(**validated_data)
+        instance = self.__class__.Meta.model(uid=uid, **validated_data)
 
         with transaction.atomic():
-            _ = self.__class__.Meta.model.objects.select_for_update().filter(owner=user)
             if etag is not None:
                 raise EtebaseValidationError("bad_etag", "etag is not null")
 

django_etebase/views.py

@@ -174,7 +174,7 @@ class CollectionViewSet(BaseViewSet):
     permission_classes = BaseViewSet.permission_classes + (permissions.IsCollectionAdminOrReadOnly,)
     queryset = Collection.objects.all()
     serializer_class = CollectionSerializer
-    lookup_field = "main_item__uid"
+    lookup_field = "uid"
     lookup_url_kwarg = "uid"
     stoken_annotation = Collection.stoken_annotation
 
@@ -246,7 +246,7 @@ class CollectionViewSet(BaseViewSet):
                 # can point to the most recent collection change rather than most recent removed membership.
                 remed_qs = remed_qs.filter(stoken__id__lte=new_stoken_obj.id)
 
-            remed = remed_qs.values_list("collection__main_item__uid", flat=True)
+            remed = remed_qs.values_list("collection__uid", flat=True)
             if len(remed) > 0:
                 ret["removedMemberships"] = [{"uid": x} for x in remed]
 
@@ -264,7 +264,7 @@ class CollectionItemViewSet(BaseViewSet):
     def get_queryset(self):
         collection_uid = self.kwargs["collection_uid"]
         try:
-            collection = self.get_collection_queryset(Collection.objects).get(main_item__uid=collection_uid)
+            collection = self.get_collection_queryset(Collection.objects).get(uid=collection_uid)
         except Collection.DoesNotExist:
             raise Http404("Collection does not exist")
         # XXX Potentially add this for performance: .prefetch_related('revisions__chunks')
@@ -312,7 +312,7 @@ class CollectionItemViewSet(BaseViewSet):
 
     @action_decorator(detail=True, methods=["GET"])
     def revision(self, request, collection_uid=None, uid=None, *args, **kwargs):
-        col = get_object_or_404(self.get_collection_queryset(Collection.objects), main_item__uid=collection_uid)
+        col = get_object_or_404(self.get_collection_queryset(Collection.objects), uid=collection_uid)
         item = get_object_or_404(col.items, uid=uid)
 
         limit = int(request.GET.get("limit", 50))
@@ -386,7 +386,7 @@ class CollectionItemViewSet(BaseViewSet):
         with transaction.atomic():  # We need this for locking on the collection object
             collection_object = get_object_or_404(
                 self.get_collection_queryset(Collection.objects).select_for_update(),  # Lock writes on the collection
-                main_item__uid=collection_uid,
+                uid=collection_uid,
             )
 
             if stoken is not None and stoken != collection_object.stoken:
@@ -435,7 +435,7 @@ class CollectionItemChunkViewSet(viewsets.ViewSet):
         return queryset.filter(members__user=user)
 
     def update(self, request, *args, collection_uid=None, collection_item_uid=None, uid=None, **kwargs):
-        col = get_object_or_404(self.get_collection_queryset(), main_item__uid=collection_uid)
+        col = get_object_or_404(self.get_collection_queryset(), uid=collection_uid)
         # IGNORED FOR NOW: col_it = get_object_or_404(col.items, uid=collection_item_uid)
 
         data = {
@@ -459,7 +459,7 @@ class CollectionItemChunkViewSet(viewsets.ViewSet):
         import os
         from django.views.static import serve
 
-        col = get_object_or_404(self.get_collection_queryset(), main_item__uid=collection_uid)
+        col = get_object_or_404(self.get_collection_queryset(), uid=collection_uid)
         # IGNORED FOR NOW: col_it = get_object_or_404(col.items, uid=collection_item_uid)
         chunk = get_object_or_404(col.chunks, uid=uid)
 
@@ -487,7 +487,7 @@ class CollectionMemberViewSet(BaseViewSet):
     def get_queryset(self, queryset=None):
         collection_uid = self.kwargs["collection_uid"]
         try:
-            collection = self.get_collection_queryset(Collection.objects).get(main_item__uid=collection_uid)
+            collection = self.get_collection_queryset(Collection.objects).get(uid=collection_uid)
         except Collection.DoesNotExist:
             raise Http404("Collection does not exist")
 
@@ -525,7 +525,7 @@ class CollectionMemberViewSet(BaseViewSet):
     @action_decorator(detail=False, methods=["POST"], permission_classes=our_base_permission_classes)
     def leave(self, request, collection_uid=None, *args, **kwargs):
         collection_uid = self.kwargs["collection_uid"]
-        col = get_object_or_404(self.get_collection_queryset(Collection.objects), main_item__uid=collection_uid)
+        col = get_object_or_404(self.get_collection_queryset(Collection.objects), uid=collection_uid)
 
         member = col.members.get(user=request.user)
         self.perform_destroy(member)
@@ -584,7 +584,7 @@ class InvitationOutgoingViewSet(InvitationBaseViewSet):
         collection_uid = serializer.validated_data.get("collection", {}).get("uid")
 
         try:
-            collection = self.get_collection_queryset(Collection.objects).get(main_item__uid=collection_uid)
+            collection = self.get_collection_queryset(Collection.objects).get(uid=collection_uid)
         except Collection.DoesNotExist:
             raise Http404("Collection does not exist")