Automatically Add Logged In User Under 'Created_By' to Model in Django Rest Framework

Question

I have a model called Properties as shown below. I'm trying to save a given property in my DB with the current logged in user from a form in my dashboard. My user model is a custom user model AUTH_USER_MODEL = 'Landlords.Profile' At first i had no created_by and all was well. But then when i introduced it, made the necessary migrations, when i try to submit data from the form i now get this error.

django.db.utils.IntegrityError: null value in column "created_by_id" of relation "Properties_rentalproperties" violates not-null constraint
DETAIL:  Failing row contains (1, Prime Apartments, Apartment, Kileleshwa, Nairobi, 10, 2021-11-07, 2021-11-07, null).

How to assign my logged in user to a the property created In Django Rest framework? Most solutions on SO are geared towards class-based API views. How can i do this with function-based API views? Is there something i'm missing or doing wrong?

My Model

from django.db import models
from django.conf import settings

class RentalProperties(models.Model):
    property_name = models.CharField(max_length=255)
    property_type = models.CharField(choices=TYPE, max_length=255)
    property_location = models.CharField(max_length=255)
    county = models.CharField(choices=COUNTY, max_length=255)
    number_of_units = models.IntegerField()
    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, default='')
    date_created = models.DateField(auto_now_add=True)
    last_modified = models.DateField(auto_now=True)

    def __str__(self):
        return self.property_name

    class Meta:
        verbose_name_plural = "Properties"

My serializer

from apps.Properties.models import RentalProperties
from rest_framework import serializers

class PropertiesSerializers(serializers.ModelSerializer):
    class Meta:
        model = RentalProperties
        fields = ('id', 'property_name', 'property_type', 'property_location', 'county', 'number_of_units', 'created_by', 'date_created', 'last_modified')

My API view

@login_required(login_url='Login' )
def AllProperties(request):
    return render(request, 'Dashboard - Properties.html')

@api_view(['POST'])
def AddPropertyAPI(request):
    serializer = PropertiesSerializers(data=request.data)
    if serializer.is_valid(raise_exception=True):
        serializer.save()
        return Response(serializer.data, status=status.HTTP_201_CREATED)
        
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Answer 1

I think that the problem is that you are trying to save RentalProperties model with created_by=null. If it is intended then allow created_by to be null by modifying your model:

created_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True, default=None)

UPDATE:

You should probably update request.data with the user sending this request, try sth like this:

@api_view(['POST'])
def AddPropertyAPI(request):
    request_data = dict(request.data)
    request_data["created_by"] = request.user if request.user.is_authenticated else None
    serializer = PropertiesSerializers(data=request_data)
    if serializer.is_valid(raise_exception=True):
        serializer.save()
        return Response(serializer.data, status=status.HTTP_201_CREATED)
        
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)