Nested write serializer validated_date is empty - django-rest-framework

Question

Followed the best practive create nested objects with serializers, however I still receive empty nested validate_data.
Serializers:
class WriteOrganisationSiteSerializer(serializers.ModelSerializer):
"""Organisation Site serializer class for post methods."""
site = WriteAPSiteSerializer()
class Meta:
model = models.OrganisationSite
fields = ("organisation", "site")
def create(self, validated_data):
from fadat.sites.models import APSite
site_data = validated_data.pop("site")
activeplaces_site_id = site_data.pop("activeplaces_site_id")
site, created = APSite.objects.get_or_create(
activeplaces_site_id=activeplaces_site_id, defaults=site_data
)
organisation_site = models.OrganisationSite.objects.create(
site=site, **validated_data
)
return organisation_site
class WriteAPSiteSerializer(serializers.Serializer):
"""Active Places Site serializer class for post methods."""
class Meta:
model = models.APSite
fields = (
"activeplaces_site_id",
"site_name",
"dependent_thoroughfare",
"thoroughfare_name",
"double_dependent_locality",
"dependent_locality",
"post_town",
"postcode",
"easting",
"northing",
"longitude",
"latitude",
)
The view
class OrganisationSitesView(APIView):
"""Organisation Sites API view."""
def post(self, request, **kwargs):
user = request.user
ser = serializers.WriteOrganisationSiteSerializer(data=request.data)
ser.is_valid(raise_exception=True)
obj = ser.save()
ser = serializers.ReadOrganisationSiteSerializer(obj)
return Response(ser.data, status=201)
Running the following test (or via browser a ajax request, same result)
def test_add_organisation_site(self):
user = User.objects.create(email="newbie#dat.example.com")
organisation_type = OrganisationType.objects.create(name="Club")
organisation = Organisation.active_objects.create(
name="Club", organisation_type=organisation_type
)
site = {
"activeplaces_site_id": 1200341,
"site_name": "CITY OF LONDON SCHOOL",
"dependent_thoroughfare": "",
"thoroughfare_name": "QUEEN VICTORIA STREET",
"double_dependent_locality": "",
"dependent_locality": "",
"post_town": "LONDON",
"postcode": "EC4V 3AL",
"easting": 531990,
"northing": 180834,
"longitude": -0.099387,
"latitude": 51.511025,
}
body = {
"organisation": organisation.id,
"site": site,
}
self.authenticate(user)
url = reverse("api:inspections:organisation-sites")
res = self.client.post(url, json.dumps(body), content_type="application/json; charset=utf-8")
self.assertEqual(res.status_code, 201)
Receiving the following headers in my views
{'organisation': 1, 'site': {'activeplaces_site_id': 1200341, 'site_name': 'CITY OF LONDON SCHOOL', 'dependent_thoroughfare': '', 'thoroughfare_name': 'QUEEN VICTORIA STREET', 'double_dependent_locality': '', 'dependent_locality': '', 'post_town': 'LONDON', 'postcode': 'EC4V 3AL', 'easting': 531990, 'northing': 180834, 'longitude': -0.099387, 'latitude': 51.511025}}
In the view the request.data show me
{'Cookie': '', 'Content-Length': '368', 'Content-Type': 'application/json; charset=utf-8', 'Authorization': 'Token 0081d8a36d90f1d922a2a7df494afe127a220495'}
Still the serialized doesn't validate nested fields and returns
{'organisation': <Organisation: Club (Club)>, 'site': OrderedDict()}

Answer 1

Right, here's what I see that needs fixing: the conventional way to design a post()method is as follows:
def post(self, request, **kwargs):
serializer = serializers.WriteOrganisationSiteSerializer(data=request.data)
serializer.is_valid(raise_exception=True)
serializer.save()
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
Although your case is in many ways equivalent, it's obviously not 100% correct. Perhaps it has to do with the fact that you're using one serializer to create the new instance, and another to show the result, when that's not needed: you can set up which fields are read_only, which ones are write_only, and those that are both read and write, as the documentation explains. I suggest you follow the schema I laid out above to guide you, and define in WriteOrganisationSiteSerializer how to show the data to the end user. Do let me know if you have any problems.