CODEWITHSUNDEEP
djangoserializationdjango-rest-framework
Thom
Thom

Reputation: 1623

How to ensure that there is at least one instance of my nested serializer in Django Rest Framework for creation?

Rather than a long explication, some code :

My main serializer OrderSerializer and the nested serializer OffersSerializer:

class OffersSerializer(serializers.Serializer):
    id = serializers.IntegerField(min_value=0)
    quantity = serializers.IntegerField(min_value=0)

class OrderSerializer(serializers.Serializer):
    offers = OffersSerializer(many=True, required=True)

With that I can POST data like this :

{
    "offers": []
}

This is valid for DRF, but I would like to check there is at least one offer, so for example:

{
    "offers": [{"id": 1, "quantity": 200}]
}

How can I ensure that there is at least one offer ?

Thank you

Upvotes: 5

Views: 1557

Answers (2)

Ykh
Ykh

Reputation: 7717

class OrderSerializer(serializers.Serializer):
    def validate_offers(self, attrs):
        if len(attrs) == 0:
            raise serializers.ValidationError('at least one offer required')
        return attrs

Upvotes: 5

Max M
Max M

Reputation: 581

Work with the Manger oder your serzializer-model, e.g.:

if (mySerializerModel.objects.all()[0] != None):
    # some code
    pass

There are other possibilities to check this. I think there is even a count() method for your managers.:

if (mySerializerModel.objects.all().count() > 0):
    # some code
    pass

Further there are mySerializerModel.objects.get(<id>) if you know the id. There might be other possibilites to check that. Just have a look at the django queryset documentation.

Upvotes: 0

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