I want to create a post request using DRF. The problem is i cant figure out how to properly make create method for a serializer in that case, so it eats an instance

I can create for example crane or chassis instance for further “Truck” creation, but can’t create a Truck instance, cause it says Chassis and Crane must be a dictionary, but I want to pass an instance of these

models.py

class Chassis(models.Model):
    id = models.BigAutoField(primary_key=True)
    brand = models.CharField(max_length=255)
    model = models.CharField(max_length=255)


class ChassisProperty(models.Model):
    id = models.BigAutoField(primary_key=True)
    chassis = models.ForeignKey(Chassis, on_delete=models.CASCADE)
    name = models.CharField(max_length=255)
    value = models.CharField(max_length=255)


class Crane(models.Model):
    id = models.BigAutoField(primary_key=True)
    brand = models.CharField(max_length=255)
    model = models.CharField(max_length=255)


class CraneProperty(models.Model):
    id = models.BigAutoField(primary_key=True)
    crane = models.ForeignKey(Crane, on_delete=models.CASCADE)
    name = models.CharField(max_length=255)
    value = models.CharField(max_length=255)


class Trucks(models.Model):
    class TruckTypes(models.TextChoices):
        FLATBED = 'FB', 'Бортовой автомобиль'
        TOW = 'TW', 'Тягач'
        DRILLING_MACHINE = 'DM', 'Буровая машина'
        LOG_CARRIER = 'LC', 'Сортиментовоз'
        MOBILE_WORKSHOP = 'MW', 'Передвижная мастерская'
        SCRAP_TRUCK = 'ST', 'Ломовоз'
        MULTILIFT = 'ML', 'Мультилифт'
        DUMP_TRUCK = 'DT', 'Самосвал'
        TANK_TRUCK = 'TT', 'Автоцистерна'
        LOADER = 'LR', 'Погрузчик'

    class WheelBases(models.TextChoices):
        SIX_TO_FOUR = '64', '6x4'
        SIX_TO_SIX = '66', '6x6'
        FOUR_TO_FOUR = '44', '4x4'
        EIGHT_TO_FOUR = '84', '8x4'
        FOUR_TO_TWO = '42', '4x2'

    id = models.BigAutoField(primary_key=True)
    chassis = models.ForeignKey(Chassis, on_delete=models.CASCADE)
    crane = models.ForeignKey(Crane, on_delete=models.CASCADE)
    truck_type = models.CharField(max_length=2, choices=TruckTypes.choices)
    wheel_base = models.CharField(max_length=2, choices=WheelBases.choices)


class TruckProperty(models.Model):
    id = models.BigAutoField(primary_key=True)
    truck = models.ForeignKey(Trucks, on_delete=models.CASCADE)
    name = models.CharField(max_length=255)
    value = models.CharField(max_length=255)

Serializers.py

import json

from rest_framework import serializers
from .models import *


class ChassisPropertySerializer(serializers.ModelSerializer):
    class Meta:
        model = ChassisProperty
        exclude = ('chassis',)


class ChassisSerializer(serializers.ModelSerializer):
    chassisproperty_set = ChassisPropertySerializer(many=True)

    class Meta:
        model = Chassis
        fields = '__all__'

    def create(self, validated_data):
        chassis_data = validated_data.pop('chassisproperty_set')
        chassis = Chassis.objects.create(**validated_data)
        for data in chassis_data:
            ChassisProperty.objects.create(chassis=chassis, **data)
        return chassis

class CranePropertySerializer(serializers.ModelSerializer):
    class Meta:
        model = CraneProperty
        exclude = ('crane',)


class CraneSerializer(serializers.ModelSerializer):
    craneproperty_set = CranePropertySerializer(many=True)

    class Meta:
        model = Crane
        fields = '__all__'

    def create(self, validated_data):
        crane_data = validated_data.pop('craneproperty_set')
        crane = Crane.objects.create(**validated_data)
        for data in crane_data:
            CraneProperty.objects.create(crane=crane, **data)
        return crane

class TruckPropertySerializer(serializers.ModelSerializer):
    class Meta:
        model = TruckProperty
        exclude = ('truck',)


class TruckSerializer(serializers.ModelSerializer):
    truckproperty_set = TruckPropertySerializer(many=True)
    chassis = ChassisSerializer(many=False)
    crane = CraneSerializer(many=False)

    truck_type = serializers.CharField(source='get_truck_type_display')
    wheel_base = serializers.CharField(source='get_wheel_base_display')

    class Meta:
        model = Trucks
        fields = '__all__'

    def create(self, validated_data):
        trucks_data = validated_data.pop('truckproperty_set')
        print(validated_data)
        truck = Trucks.objects.create(**validated_data)
        for truck_data in trucks_data:
            TruckProperty.objects.create(truck=truck, **truck_data)
        return truck

And views.py

from rest_framework import viewsets

from .serializers import *
from .models import *


class TrucksViewSet(viewsets.ModelViewSet):
    queryset = (Trucks.objects.prefetch_related(
        'chassis__trucks_set',
        'chassis__chassisproperty_set',
        'crane__trucks_set',
        'crane__craneproperty_set'
    ).all())
    serializer_class = TruckSerializer


class ChassisViewSet(viewsets.ModelViewSet):
    queryset = Chassis.objects.prefetch_related('chassisproperty_set')
    serializer_class = ChassisSerializer


class CraneViewSet(viewsets.ModelViewSet):
    queryset = Crane.objects.prefetch_related('craneproperty_set')
    serializer_class = CraneSerializer