Fixes #1421: Improved model validation logic for API serializers

netbox/utilities/api.py

@@ -8,7 +8,7 @@ from rest_framework.compat import is_authenticated
 from rest_framework.exceptions import APIException
 from rest_framework.pagination import LimitOffsetPagination
 from rest_framework.permissions import BasePermission, DjangoModelPermissions, SAFE_METHODS
-from rest_framework.serializers import Field, ValidationError
+from rest_framework.serializers import Field, ModelSerializer, ValidationError
 
 from users.models import Token
 
@@ -80,6 +80,21 @@ class IsAuthenticatedOrLoginNotRequired(BasePermission):
 # Serializers
 #
 
+class ValidatedModelSerializer(ModelSerializer):
+    """
+    Extends the built-in ModelSerializer to enforce calling clean() on the associated model during validation.
+    """
+    def validate(self, attrs):
+        if self.instance is None:
+            instance = self.Meta.model(**attrs)
+        else:
+            instance = self.instance
+            for k, v in attrs.items():
+                setattr(instance, k, v)
+        instance.clean()
+        return attrs
+
+
 class ChoiceFieldSerializer(Field):
     """
     Represent a ChoiceField as {'value': <DB value>, 'label': <string>}.
@@ -121,17 +136,6 @@ class ContentTypeFieldSerializer(Field):
 # Mixins
 #
 
-class ModelValidationMixin(object):
-    """
-    Enforce a model's validation through clean() when validating serializer data. This is necessary to ensure we're
-    employing the same validation logic via both forms and the API.
-    """
-    def validate(self, attrs):
-        instance = self.Meta.model(**attrs)
-        instance.clean()
-        return attrs
-
-
 class WritableSerializerMixin(object):
     """
     Allow for the use of an alternate, writable serializer class for write operations (e.g. POST, PUT).