Conversion of `models.JSONField`

[benoit9126]

Hi!

I am using ninja_extra.ModelConfig class in order to generate an API for a Django model which has a models.JSONField field. The converter internally used by ninja_schema to get a Pydantic field from the Django field is:

# from ninja_schema.orm.utils.converter.py

@t.no_type_check
@convert_django_field.register(models.JSONField)
def convert_field_to_json_string(
    field: Field, **kwargs: DictStrAny
) -> t.Tuple[t.Type, PydanticField]:
    python_type = Json
    if field.null:
        python_type = t.Optional[Json]
    return construct_field_info(python_type, field)

Unfortunately, the Json Pydantic field expects serialized data as input. When reading an object with a models.JSONField field from the database, Django retrieves a dict (not string, bytes or bytearray) for this field. This leads to this validation error from Pydantic:

JSON input should be string, bytes or bytearray [type=json_type, input_value={'values': [1], 'numbers': []}, input_type=dict]

I think that the Pydantic Json field is perfect for a create_schema or update_schema as their data comes from the HTTP request. But, in the case of a retrieve_schema, the python_type should be a dict (not Json) as there is no conversion to perform.

NB: I have manually defined a retrieve_schema using the dict field to bypass this problem.

[eadwinCode]

@benoit9126 I will look into this

[benoit9126]

@eadwinCode Thanks a lot! As I wrote in my message, I can easily bypass the error, so no emergency in this issue 😊

[eadwinCode]

Yeaaah, I read the NB. But it's still worth looking into