Django REST Framework serializer field required=false

Question

from the documentation:

read_only Set this to True to ensure that the field is used when serializing a representation, but is not used when updating

Answer 1

I suppose method .get_validation_exclusions() is now removed. I did not found it in ModelSerializer doc and it did not execute after override (djangorestframework==3.8.2). And i am not the only one facing this problem.

My solution is to just add default value for field which i want to be non-required. It supposed to be fine specifically for situations with pre_save:

class FavoriteListSerializer(serializers.ModelSerializer):
    owner = serializers.IntegerField(default='')
    class Meta:
        model = models.FavoriteList

You also have to keep in mind that using drf serializers with pre_save signals may cause implicit behavour (i did not check, but it seems to be logical):

pre_save is called on pre object save (incredible) which (probably) means after serializer validation.