Filter model with serializer.validated_data - django

Question

I am setting up a Django REST application where peopple can review restaurants. So far I have those models:
class RestaurantId(models.Model):
maps_id = models.CharField(max_length=140, unique=True)
adress = models.CharField(max_length=240)
name = models.CharField(max_length=140)
class RestaurantReview(models.Model):
review_author = models.ForeignKey(settings.AUTH_USER_MODEL,
on_delete=models.CASCADE)
restaurant_id = models.ForeignKey(RestaurantId, on_delete=models.CASCADE)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
class StarterPics(models.Model):
restaurant_review_id = models.OneToOneField(RestaurantReview,
on_delete=models.CASCADE)
pics_author = models.ForeignKey(User, on_delete=models.CASCADE)
restaurant_id = models.ForeignKey(RestaurantId, on_delete=models.CASCADE)
name_1 = models.CharField(max_length=40)
picture_1 = models.ImageField()
My serializers:
class RestaurantIdSerializer(serializers.ModelSerializer):
class Meta:
model = RestaurantId
field = fields = '__all__'
class RestaurantReviewSerializer(serializers.ModelSerializer):
class Meta:
model = RestaurantReview
field = fields = '__all__'
class StarterPicsSerializer(serializers.ModelSerializer):
class Meta:
model = StarterPics
fields = '__all__'
def validate_restaurant_review_id(self, value)
if value.review_author != self.request.user:
raise serializers.ValidationError("User has not reviewed the restaurant")
return value
My views:
class RestaurantIdViewset(viewsets.ModelViewSet):
queryset = models.RestaurantId.objects.all()
serializer_class = serializers.RestaurantIdSerializer
class RestaurantReviewViewset(viewsets.ModelViewSet):
queryset = models.RestaurantReview.objects.all()
serializer_class = serializers.RestaurantReviewSerializer
permission_classes = [IsAuthenticatedOrReadOnly,IsAuthorOrReadOnly]
def perform_create(self, serializer):
serializer.save(review_author=self.request.user)
class StarterPicsViewset(viewsets.ModelViewSet):
queryset = models.StarterPics.objects.all()
serializer_class = serializers.StarterPicsSerializer
permission_classes = [IsAuthenticatedOrReadOnly]
I have set up permissions as well so only the review_author can update his reviews and pics_author can update his pictures.
My permissions:
class IsOwnReviewOrReadOnly(permissions.BasePermission):
def has_object_permission(self, request, view, obj):
if request.method in permissions.SAFE_METHODS:
return True
return obj.pics_author == request.user
class IsAuthorOrReadOnly(permissions.BasePermission):
def has_object_permission(self, request, view, obj):
if request.method in permissions.SAFE_METHODS:
return True
return obj.review_author == request.user
Now what I have is that posting a StarterPics on a review that someone is not the author is imposible. That is the behaviour I am looking for. But if the review author tries to do so I have this error:
TypeError: Field 'id' expected a number but got <RestaurantReview: 8>.
Here is my serializer.validated_data:
OrderedDict([('name_1', 'Salade de saison'), ('picture_1', <InMemoryUploadedFile: fricoteurs_inside.jpeg (image/jpeg)>),
('name_2', ''), ('picture_2', None), ('lat_pic_2', None), ('lng_pic_2', None),
('shot_time_2', None), ('restaurant_review_id', <RestaurantReview: 8>), ('pics_author', <User: pi>), ('restaurant_id', <RestaurantId: Les Fricoteurs>)])
Because I cannot call .save() after accessing serializer.data I can't get the 'restaurant_review_id': 4 I would have if I was using serializer.data.
So how can I filter my RestaurantReview model using serializer.validated_data?

Answer 1

This validation should be done in serializer field level, not in perform_create() method:
class StarterPicsSerializer(serializers.ModelSerializer):
...
def validate_resturant_review_id(self, value):
if value.review_user != self.context['request'].user:
raise serializers.ValidationError("User has not reviewed the resturant")
return value