ForiegnKey field serializer in Django Rest framewo

Before posting this question I've read few questions on SOF. but they are from 2012 and very confusing as well. for e.g Django Rest Framework - Get related model field in serializer

my question is very straight forward

models.py

class User(models.Model):
    username = models.CharField(max_length=100,unique=True)
    password = models.CharField(max_length=100,null=False,blank=False)

class Car(models.Model):
    user = models.ForeignKey(User)
    car_name = models.CharField(max_length=100,null=True,blank=True)

serializers.py

class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('username','password' )

class CarSerializer(serializers.ModelSerializer):
    #user = ?? what should I write or is there any better approach for serializing Car objects
    class Meta:
        model = Car
        fields = ('user','car_name')

views.py

class UserViewSet(viewsets.ModelViewSet):
    queryset = User.objects.all()
    serializer_class = UserSerializer

class CarViewSet(viewsets.ModelViewSet):
    queryset = Car.objects.all()
    serializer_class = CarSerializer

Please suggest all possible approaches.

1 more query. which one is better ModelSerializer or HyperlinkModelSerializer. as I saw different different answers containing these two.

You just need to do:

class CarSerializer(serializers.ModelSerializer):
    user = UserSerializer()
    class Meta:
        model = Car
        fields = ('user','car_name')

that is all.

Also, you should take a look to the kindnesses of serializers.Field and serializers.SerializerMethodField, you can play with them and customize your response data as much as you wish.

As to the question around HyperlinkedModelSerializer-ModelSerializer, very clear here:

The HyperlinkedModelSerializer has the following differences from ModelSerializer:

It does not include the pk field by default.
It includes a url field, using HyperlinkedIdentityField.
Relationships use HyperlinkedRelatedField, instead of PrimaryKeyRelatedField.

Hope that helps.