Django Serializer defining initial object - django

Question

I can't seem to figure out how to pass in an initial value to a serializer. I have a multitenant django site and I am trying to now get APIs setup. The client field exists but needs to be hidden and read only. I thought this worked like a form and a view in traditional django. I would normally pass in the get_initial in the view. I tried that first but it doesn't work. I think I need to get the value directly in the serializer but I can't seem to get it to work.
model:
class Location(ClientAwareModel):
name = models.CharField(max_length=64, blank=True)
address = models.CharField(max_length=64)
address2 = models.CharField(max_length=64, blank=True)
city = models.CharField(max_length=64)
state = USStateField()
zip_code = USZipCodeField()
class Client(models.Model):
name = models.CharField(max_length=100)
subdomain_prefix = models.CharField(max_length=100, unique=True)
def __str__(self):
return self.name
class ClientAwareModel(models.Model):
client = models.ForeignKey(Client, on_delete=models.PROTECT)
class Meta:
abstract = True
def hostname_from_request(request):
# split on `:` to remove port
return request.get_host().split(':')[0].lower()
def client_from_request(request):
hostname = hostname_from_request(request)
subdomain_prefix = hostname.split('.')[0]
return Client.objects.filter(subdomain_prefix=subdomain_prefix).first()
serializer (you can see all my failed attempts commented out:
class LocationSerializer(serializers.ModelSerializer):
def get_client(self, obj):
# return client_from_request(self.request)
return client_from_request(self.context['request'])
# client = serializers.SerializerMethodField('get_client')
# client = serializers.SerializerMethodField()
# client = serializers.Field(source='get_client', read_only=True)
# client = serializers.ReadOnlyField(source='get_client')
# client = serializers.PrimaryKeyRelatedField(read_only=True, default='get_client')
client = serializers.PrimaryKeyRelatedField(read_only=True, source='get_client')
# client = serializers.HiddenField(default=get_client(self))
class Meta:
model = Location
fields = ['name', 'address', 'address2', 'city', 'state', 'zip_code', 'client']
viewset:
class LocationViewSet(viewsets.ModelViewSet):
queryset = Location.objects.all()
serializer_class = LocationSerializer
permission_classes = [permissions.IsAuthenticated]
def get_queryset(self):
client = client_from_request(self.request)
return super().get_queryset().filter(client=client)
you can see the different ways I tried to pass in the value but no matter what I do I get
IntegrityError at /locations/
null value in column "client_id" violates not-null constraint

Answer 1

One easy way to pass the client object to serializer is to pass it in perform_create method, something like:
from rest_framework import serializers
class LocationViewSet(viewsets.ModelViewSet):
queryset = Location.objects.all()
serializer_class = LocationSerializer
permission_classes = [permissions.IsAuthenticated]
def get_queryset(self):
client = client_from_request(self.request)
return super().get_queryset().filter(client=client)
def perform_create(self, serializer):
client = client_from_request(self.request)
if not client:
raise serializers.ValidationError("Client does not exist")
serializer.save(client=client)
And also remove the client field from your serializer:
class LocationSerializer(serializers.ModelSerializer):
class Meta:
model = Location
fields = ['name', 'address', 'address2', 'city', 'state', 'zip_code']

Answer 2

In your viewset you are trying to get Location by filtering Client when your Location model does not have a Client FK.
Right here:
def get_queryset(self):
client = client_from_request(self.request)
return super().get_queryset().filter(client=client) <----
As #gregory mentioned in the comment above, adding Foreign Key would solve your problem, then you can just simply add it to your serializer.