CODEWITHSUNDEEP
django-rest-framework
abhaga
abhaga

Reputation: 5455

Correctly instantiating a DRF ModelField

I am trying to use ModelField to serialize a JSONField. I am not quite sure what is the expected thing to be passed into 'model_field' kwarg. Passing the class name doesn't cut it since the ModelField seems to be storing the 'model_field' directly and calling methods on that. 

== restapi.py ==

    reading_order = ModelField(model_field=JSONField) # Corresponds to a JSONField 'reading_order' in my model.

== rest_framework/fields.py ModelField ==

def field_to_native(self, obj, field_name):
    value = self.model_field._get_val_from_obj(obj)

This results in error saying that first argument should be an instance to JSONField which makes sense since self.model_field is the class definition. If I change it to:

def field_to_native(self, obj, field_name):
    value = self.model_field._get_val_from_obj(obj._meta.get_field(field_name), obj)

It works fine.

I am not sure if this is a bug I have stumbled upon or if I am instantiating the ModelField wrong. Can someone please point me to right way to use ModelField?

Regards, Abhaya

Upvotes: 1

Views: 1610

Answers (1)

Tom Christie
Tom Christie

Reputation: 33901

Believe that's a docs issue. ModelField should be passed a field instance, not a field class, so you should instantiate the model field like so:

 reading_order = ModelField(model_field=JSONField())

Upvotes: 1

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