PATCH method not working in Django ModelViewSet

Question

I'm having trouble in using patch method inside a ModelViewSet for my custom User model. Here is the code:

views.py

@permission_classes([IsAdminUser])
    class UserViewSet(viewsets.ModelViewSet):
    queryset = User.objects.all()
    serializer_class = UserSerializer
    http_method_names = ['get', 'post', 'patch', 'head', 'delete']

serializers.py

class UserSerializer(serializers.ModelSerializer):
class Meta:
    model = User
    fields = ('id',
              'email',
              'password',
              'is_active',
              'is_staff',
              'is_admin')
    extra_kwargs = {'password': {'write_only': True, 'required': True},
                    'is_active': {'default': True},
                    'is_staff': {'default': False},
                    'is_admin': {'default': False}}

def create(self, validated_data):
    self.is_valid(raise_exception=True)
    if validated_data['is_admin']:
        validated_data['is_staff'] = True
    user = User.objects.create_user(**validated_data)
    return user

def update(self, instance, validated_data):
    instance.email = validated_data.get('email')
    instance.is_active = validated_data.get('is_active')
    instance.is_staff = validated_data.get('is_staff')
    instance.is_admin = validated_data.get('is_admin')
    if instance.is_admin:
        instance.is_staff = True
    instance.save()
    return instance

I set a permission in order to allow only superuser to access this view. The problem comes when trying to perform a patch. For example, if I try to change is_staff attribute to False of a User using Postman with PATCH and "http://localhost:8000/users/USER_ID", I get the following error:

django.db.utils.IntegrityError: null value in column "email" violates not-null constraint DETAIL: Failing row contains (1, pbkdf2_sha256$180000$6jePqBspO6xK$tCQ9zZk1uOdJD2F7L9BQRFFDbz1GXJ..., 2020-04-18 20:02:57.052639+00, null, t, t, t).

It seems like django asks me to provide every single field fo User model (email, is_active, is_staff, is_admin), which it doesn't make sense in my opinion givien that it's a PATCH request. To overcome the issue, I've modified the update method of my UserSerializer like that:

    def update(self, instance, validated_data):
        if validated_data.get('email') is not None:
            instance.email = validated_data.get('email')
        if validated_data.get('is_active') is not None:
            instance.is_active = validated_data.get('is_active')
        if validated_data.get('is_staff') is not None:
            instance.is_staff = validated_data.get('is_staff')
        if validated_data.get('is_admin') is not None:
            instance.is_admin = validated_data.get('is_admin')
        if instance.is_admin:
            instance.is_staff = True
        instance.save()
        return instance

It works now, but I'd like to know whether this is a good solution. In my opinion, it is not a "canonical" way for solving the problem. I've also tried to override partial_update method (following others StackOverflow's answers) inside my UserViewSet, with no results.

Does this answer your question? How to make a PATCH request using DJANGO REST framework — iklinac
– iklinac, Commented Apr 19, 2020 at 16:29
the problem I think in route and URL, not view, you have to remove http_method_name — faruk
– faruk, Commented Oct 8, 2021 at 20:01

dcfg · Accepted Answer · 2020-04-19 20:10:11Z

0

I've found very useful this previous post django-rest-framework-serializer-update-method-does-not-save-object The problem was in the serializer. I've changed the overwritten update method inside my UserSerializer and now PATCH works

def update(self, instance, validated_data):
    if validated_data.get('is_admin'):
        validated_data['is_staff'] = True
    return super().update(instance, validated_data)

NOTE: no need to override any method in the view, just add 'patch' to http_method_names list

answered Apr 19, 2020 at 20:10

dcfg

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