From 50f3e8f9ff1f532f61b29f2caaa8657b2ea8f9b0 Mon Sep 17 00:00:00 2001
From: Anna Shamray <anna.shamray@maykinmedia.nl>
Date: Wed, 18 Nov 2020 18:18:38 +0100
Subject: [PATCH] :sparkles: add validators to API since it's writable now

---
 src/objecttypes/api/serializers.py |  8 ++++++-
 src/objecttypes/api/validators.py  | 38 ++++++++++++++++++++++++++++++
 src/objecttypes/core/models.py     | 11 ++-------
 src/objecttypes/core/utils.py      | 12 ++++++++++
 4 files changed, 59 insertions(+), 10 deletions(-)
 create mode 100644 src/objecttypes/api/validators.py
 create mode 100644 src/objecttypes/core/utils.py

diff --git a/src/objecttypes/api/serializers.py b/src/objecttypes/api/serializers.py
index c33eee42..f88ce5ee 100644
--- a/src/objecttypes/api/serializers.py
+++ b/src/objecttypes/api/serializers.py
@@ -4,6 +4,8 @@
 
 from objecttypes.core.models import ObjectType, ObjectVersion
 
+from .validators import JsonSchemaValidator, VersionUpdateValidator
+
 
 class ObjectVersionSerializer(NestedHyperlinkedModelSerializer):
     parent_lookup_kwargs = {"objecttype_uuid": "object_type__uuid"}
@@ -27,9 +29,13 @@ class Meta:
                 "read_only": True,
             },
             "publicationDate": {"source": "publication_date", "read_only": True},
-            "jsonSchema": {"source": "json_schema"},
+            "jsonSchema": {
+                "source": "json_schema",
+                "validators": [JsonSchemaValidator()],
+            },
             "status": {"read_only": True},
         }
+        validators = [VersionUpdateValidator()]
 
     def create(self, validated_data):
         kwargs = self.context["request"].resolver_match.kwargs
diff --git a/src/objecttypes/api/validators.py b/src/objecttypes/api/validators.py
new file mode 100644
index 00000000..a3883274
--- /dev/null
+++ b/src/objecttypes/api/validators.py
@@ -0,0 +1,38 @@
+from django.core.exceptions import ValidationError
+from django.utils.translation import ugettext_lazy as _
+
+from rest_framework import serializers
+
+from objecttypes.core.constants import ObjectVersionStatus
+from objecttypes.core.utils import check_json_schema
+
+
+class VersionUpdateValidator:
+    message = _("Only draft versions can be changed")
+    code = "non-draft-object"
+
+    def set_context(self, serializer):
+        """
+        This hook is called by the serializer instance,
+        prior to the validation call being made.
+        """
+        # Determine the existing instance, if this is an update operation.
+        self.instance = getattr(serializer, "instance", None)
+        self.request = serializer.context["request"]
+
+    def __call__(self, attrs):
+        if not self.instance:
+            return
+
+        if self.instance.status != ObjectVersionStatus.draft:
+            raise serializers.ValidationError(self.message, code=self.code)
+
+
+class JsonSchemaValidator:
+    code = "invalid-json-schema"
+
+    def __call__(self, value):
+        try:
+            check_json_schema(value)
+        except ValidationError as exc:
+            raise serializers.ValidationError(exc.args[0], code=self.code) from exc
diff --git a/src/objecttypes/core/models.py b/src/objecttypes/core/models.py
index 1f25d830..3025df54 100644
--- a/src/objecttypes/core/models.py
+++ b/src/objecttypes/core/models.py
@@ -2,18 +2,15 @@
 from datetime import date
 
 from django.contrib.postgres.fields import JSONField
-from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
-from jsonschema.exceptions import SchemaError
-from jsonschema.validators import validator_for
-
 from .constants import (
     DataClassificationChoices,
     ObjectVersionStatus,
     UpdateFrequencyChoices,
 )
+from .utils import check_json_schema
 
 
 class ObjectType(models.Model):
@@ -147,11 +144,7 @@ def __str__(self):
     def clean(self):
         super().clean()
 
-        schema_validator = validator_for(self.json_schema)
-        try:
-            schema_validator.check_schema(self.json_schema)
-        except SchemaError as exc:
-            raise ValidationError(exc.args[0]) from exc
+        check_json_schema(self.json_schema)
 
     def save(self, *args, **kwargs):
         if not self.version:
diff --git a/src/objecttypes/core/utils.py b/src/objecttypes/core/utils.py
new file mode 100644
index 00000000..a0d7dd78
--- /dev/null
+++ b/src/objecttypes/core/utils.py
@@ -0,0 +1,12 @@
+from django.core.exceptions import ValidationError
+
+from jsonschema.exceptions import SchemaError
+from jsonschema.validators import validator_for
+
+
+def check_json_schema(json_schema: dict):
+    schema_validator = validator_for(json_schema)
+    try:
+        schema_validator.check_schema(json_schema)
+    except SchemaError as exc:
+        raise ValidationError(exc.args[0]) from exc