DRF - serializer drops nested serializers - django

Question

TL;DR: DRF drops the inner serialized object when validating the outermost serializer.
I'm using django 2.0, django-rest-framework 3.7.7, python 3.
I want to build a REST endpoint that performs a search in the database, using some parameters received in a POST (I want to avoid GET calls, which could be cached). The parameters should act like ORs (that's why I set all fields as not required), and I'm solving that using django Q queries when extracting the queryset.
I have the following django models in app/models.py:
class Town(models.Model):
name = models.CharField(max_length=200)
province = models.CharField(max_length=2, blank=True, null=True)
zip = models.CharField(max_length=5)
country = models.CharField(max_length=100)
class Person(models.Model):
name = models.CharField(max_length=100)
birth_place = models.ForeignKey(Town, on_delete=models.SET_NULL,
null=True, blank=True,
related_name="birth_place_rev")
residence = models.ForeignKey(Town, on_delete=models.SET_NULL,
null=True, blank=True,
related_name="residence_rev")
And I wrote the following serializers in app/serializers.py:
class TownSerializer(serializers.ModelSerializer):
class Meta:
model = models.Town
fields = ("id", "name", "province", "zip", "country")
def __init__(self, *args, **kwargs):
super(TownSerializer, self).__init__(*args, **kwargs)
for field in self.fields:
self.fields[field].required = False
class PersonSerializer(serializers.ModelSerializer):
birth_place = TownSerializer(read_only=True)
residence = TownSerializer(read_only=True)
class Meta:
model = models.Person
fields = ("id", "name", "birth_place", "residence")
def __init__(self, *args, **kwargs):
super(PersonSerializer, self).__init__(*args, **kwargs)
for field in self.fields:
self.fields[field].required = False
Then I wrote a view to provide the REST interface, in api/views.py:
class PersonSearchList(views.APIView):
model_class = Person
serializer_class = PersonSerializer
permission_classes = (permissions.AllowAny,)
def post(self, request, format=None):
serializer = self.serializer_class(data=request.data)
print("initial_data", serializer.initial_data) ########
if serializer.is_valid():
self.data = serializer.validated_data
print(self.data) ########
queryset = self.get_queryset()
serialized_objects = self.serializer_class(queryset, many=True)
return Response(serialized_objects.data, status=status.HTTP_201_CREATED)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
def get_queryset(self, *args, **kwargs):
orig_queryset = self.model_class.objects.all()
query_payload = self.data
# .. perform filtering using the query_payload data.
return queryset
And when I try to perform a query using e.g. curl:
$ curl -s -X POST -H "Content-Type: application/json" --data '{"birth_place": {"name": "Berlin", "country": "Germany"}}' http://127.0.0.1:8000/persons/ |python -m json.tool
[]
even though a Person object with birth_place set accordingly has just been created.
The two print statements that I placed in the post method of the view return:
initial_data: {'birth_place': {'name': 'Berlin', 'country': 'Germany'}}
after is_valid: OrderedDict()
So it seems like DRF drops the nested relation when validates.
How should I specify to parse and validate also the nested relation? Any suggestion is appreciated.
PS: Am I forcing a wrong design by making the request with a POST? I thought that since a search is not idempotent, and it may contain sensitive data (name, surname, birth date, etc) of a person.
I need an action which is safe (a search doesn't change the data) but not idempotent (a search in two different times can be different).
Initially I started using a generics.ListAPIView, but list() works only with GET. If there's a way to make it accept POST requests it would work like a charm.

Answer 1

As #Jon Clements♦ mentioned in comments, this would solve your problem
class PersonSerializer(serializers.ModelSerializer):
birth_place = TownSerializer()
residence = TownSerializer()
class Meta:
model = Person
fields = ("id", "name", "birth_place", "residence")
def __init__(self, *args, **kwargs):
super(PersonSerializer, self).__init__(*args, **kwargs)
for field in self.fields:
self.fields[field].required = False