Django REST Framework - serializer users

Question

I would like to add new offer using username instead of userID .

Could you please advise how this should be managed with user_receiver ?

models.py

User = get_user_model()

class Offer(models.Model):
    user_sender = models.ForeignKey(User, related_name='user_sender', on_delete=models.CASCADE)
    user_receiver = models.ForeignKey(User, related_name='user_receiver', on_delete=models.CASCADE)

serializer.py

class OfferSerializer(serializers.ModelSerializer):
    current_user = serializers.CharField(default=serializers.CurrentUserDefault())
    user_receiver = ???

    class Meta:
        model = Offer
        fields = ('user_sender', 'user_receiver')

Answer 1

You can try :

serializer.py

class OfferSerializer(serializers.ModelSerializer):

    current_user = serializers.PrimaryKeyRelatedField(
        read_only=True, 
        default=serializers.CurrentUserDefault()
    )

    user_receiver = serializers.SerializerMethodField()
    user_sender = serializers.SerializerMethodField()

    class Meta:
        model = Offer
        fields = ('user_sender', 'user_receiver')

    def get_user_receiver(self , obj):
        return self.context['request'].user.user_receiver

    def get_user_sender(self , obj):
        return self.context['request'].user.user_sender