ValueError: badly formed hexadecimal UUID string

Question

In my system I'm trying to auto generate a unique random string for each users to be passed later on in the URL as the reference to that account and I recently read about the UUID in django models. And this is how my model looks like:

class User(AbstractBaseUser, PermissionsMixin):
    card_number = models.CharField(max_length=20, unique=True)
    first_name = models.CharField(max_length=150)
    middle_name = models.CharField(max_length=150)
    last_name = models.CharField(max_length=150)
    address = models.CharField(max_length=200)
    account_code = models.UUIDField(max_length=200, default=uuid.uuid4(), editable=False)

And I ran into an error when start creating superuser in the terminal:

Traceback (most recent call last):
  File "C:\Users\User\PycharmProjects\ViajeroProject\viaje\manage.py", line 22, in <module>
    main()
  File "C:\Users\User\PycharmProjects\ViajeroProject\viaje\manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\core\management\__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\core\management\__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\core\management\base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\contrib\auth\management\commands\createsuperuser.py", line 79, in execute
    return super().execute(*args, **options)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\core\management\base.py", line 371, in execute
    output = self.handle(*args, **options)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\contrib\auth\management\commands\createsuperuser.py", line 113, in handle
    error_msg = self._validate_username(username, verbose_field_name, database)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\contrib\auth\management\commands\createsuperuser.py", line 234, in _validate_username
    self.UserModel._default_manager.db_manager(database).get_by_natural_key(username)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\contrib\auth\base_user.py", line 45, in get_by_natural_key
    return self.get(**{self.model.USERNAME_FIELD: username})
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\models\manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\models\query.py", line 425, in get
    num = len(clone)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\models\query.py", line 269, in __len__
    self._fetch_all()
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\models\query.py", line 1308, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\models\query.py", line 70, in __iter__
    for row in compiler.results_iter(results):
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\models\sql\compiler.py", line 1100, in apply_converters
    value = converter(value, expression, connection)
  File "C:\Users\User\PycharmProjects\ViajeroProject\venv\lib\site-packages\django\db\backends\sqlite3\operations.py", line 318, in convert_uuidfield_value
    value = uuid.UUID(value)
  File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\uuid.py", line 177, in __init__
    raise ValueError('badly formed hexadecimal UUID string')
ValueError: badly formed hexadecimal UUID string

How should I address this or is this practice not advisable where I auto generate a unique random string as reference for the user in the URL? Note that users still have their PKs which different from the account_code.

Thank you!

Answer 1

You need to import the module and use default=uuid.uuid4 instead of default=uuid.uuid4()