Benutzerdefiniertes Django-Modellfeld zur erzwungenen validierten JSON-Speicherung

from django.db import models
from django.core.exceptions import ValidationError
import json
 
class ValidatedJSONField(models.TextField):
    """Stores dict objects as JSON strings with structural schema validation."""
    def to_python(self, value):
        if value is None or isinstance(value, dict):
            return value
        try:
            parsed = json.loads(value)
            if not isinstance(parsed, dict):
                raise ValidationError("JSON root content must be a dictionary object.")
            return parsed
        except json.JSONDecodeError as err:
            raise ValidationError(f"Invalid JSON payload syntax: {err}")
 
    def get_prep_value(self, value):
        if value is None:
            return value
        return json.dumps(value)