Data Dissapearing in Django on validation - django

Question

I am trying to create nested objects (documentregulation) when I create a Document object. To achieve this, I have overwritten the create method on the DocumentSerializer, as per Django Docs. However, when I attempt validated_data.pop('documentregulation_set'), it is empty, even when it is populated in the incoming request.data of my view. Is there something causing my incoming data to not be validated? How would I go about debugging this if so?
// serializers.py
class DocumentRegulationSerializer(serializers.ModelSerializer):
class Meta:
model = DocumentRegulation
fields = ('regulation',)
class DocumentSerializer(serializers.ModelSerializer):
documentregulation_set = DocumentRegulationSerializer(many=True, required=False)
class Meta:
model = Document
fields = ('documentregulation_set', 'id', 'name', 'file', 'text', 'uploaded_at')
extra_kwargs = {
'id': {'read_only': True},
'uploaded_at': {'read_only': True},
}
def create(self, validated_data):
documentregulation_set = validated_data.pop('documentregulation_set')
# create document first
document = Document.objects.create(**validated_data)
# serialize associated regulations
for documentregulation in documentregulation_set:
# get ID of newly-created document, use for relation
#documentregulation['regulation'] = documentregulation['id']
DocumentRegulation.objects.create(document=document, **documentregulation)
return document
//views.py
class DocumentView(generics.ListCreateAPIView):
def create(self, request):
#pprint(self.request.FILES['profile_pic'])
request.data['documentregulation_set'] = json.loads(request.data['documentregulation_set'])
request.data['documentdomain_set'] = json.loads(request.data['documentdomain_set'])
pprint(request.data)
document = DocumentSerializer(data=request.data)
if document.is_valid():
document.save()
return Response(document.data, status=status.HTTP_201_CREATED)
else:
return Response(document.errors, status=status.HTTP_400_BAD_REQUEST)
my incoming data (printed in request.data) looks like:
{'documentregulation_set': [{'label': 'Regulation 1',
'regulation': 2,
'value': 2},
{'label': 'Regulation 2',
'regulation': 4,
'value': 4}],
'file': <InMemoryUploadedFile: test.docx >,
'name': 'testing',
'text': 'test'}
but then my validated data prints out to be:
{'documentregulation_set': [],
'file': <InMemoryUploadedFile: test.docx >,
'name': 'testing',
'text': 'test'}

Answer 1

Problem seems to be with the validation of the documentregulation_set field in the DocumentSerializer serializer. But you can escape the validation in the Meta Class as:
class Meta:
model = Document
fields = '__all__'
extra_kwargs = {
'documentregulation_set': {'validators': []} # escape validation
}
If you need to write custom validators have a look at Writing custom validators
So the final serializer looks like:
class DocumentRegulationSerializere(serializers.ModelSerializer):
"""Serializers for DocumentRegulation object"""
class Meta:
model = DocumentRegulation
fields = ('regulation',)
class DocumentSerializer(serializers.ModelSerializer):
"""Serializer for Document objects"""
documentregulation_set = DocumentRegulationSerializere(many=True)
class Meta:
model = Document
fields = ('documentregulation_set', 'id', 'name', 'file', 'text', 'uploaded_at')
extra_kwargs = {
'id': {'read_only': True},
'uploaded_at': {'read_only': True},
'documentregulation_set': {'validators': []} # escape validation
}
def create(self, validated_data):
doc_reg = []
document_regulation_set = validated_data.pop('documentregulation_set')
document = Document.objects.create(**validated_data)
for document_regulation in document_regulation_set:
reg = DocumentRegulation.objects.create(**document_regulation)
reg.save()
doc_reg.append(reg)
document.documentregulation_set.add(reg)
return document
View
class DocumentView(generics.ListCreateAPIView):
"""List or create new Document ojects"""
queryset = Document.objects.all()
serializer_class = DocumentSerializer