python - 关于FK模型继承的django动态相关名称

Question

我正在尝试通过对另一个类属性执行操作来动态设置类属性。我的代码是这样的

class LastActionModel(BaseModel):
    """
    Provides created_by updated_by fields if you have an instance of user,
    you can get all the items, with Item being the model name, created or updated
    by user using user.created_items() or user.updated_items()
    """
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL, blank=True, null=True,
        related_name = lambda self:'%s_%s' %('created', \
            self._meta.verbose_name_plural.title().lower())
    )
    updated_by = models.ForeignKey(
        settings.AUTH_USER_MODEL, blank=True, null=True,
        related_name = lambda self:'%s_%s' %('updated', \
            self._meta.verbose_name_plural.title().lower())
    )

    class Meta:
        abstract = True

这是为了动态设置相关名称，以便对于类 Item 和用户 'user'，我可以轻松调用 user.created_items.all()。

这是给我的错误

super(ForeignObject, self).contribute_to_class(cls, name, virtual_only=virtual_only)
    File "/home/pywebapp/venv/local/lib/python2.7/site-packages/django/db/models/fields/related.py", line 113, in contribute_to_class
        'app_label': cls._meta.app_label.lower()
TypeError: Error when calling the metaclass bases
    unsupported operand type(s) for %: 'function' and 'dict'

我哪里错了？

Answer 1

答案很简单，根据 docs

class LastActionModel(BaseModel):
    """
    Provides created_by updated_by fields if you have an instance of user,
    you can get all the items, with Item being the model name, created or updated
    by user using user.created_items() or user.updated_items()
    """
    created_by = models.ForeignKey(
        'users.User', blank=True, null=True,
        related_name = 'created_%(class)ss'
    )
    updated_by = models.ForeignKey(
        'users.User', blank=True, null=True,
        related_name = 'updated_%(class)ss'
    )

    class Meta:
        abstract = True

希望对你有帮助