python 将属性添加到 Django 模型的 Meta 类中
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Adding attributes into Django Model's Meta class
提问by Andrey Fedorov
I'm writing a mixin which will allow my Models to be easily translated into a deep dict of values (kind of like .values(), but traversing relationships). The cleanest place to do the definitions of these seems to be in the models themselves, a la:
我正在编写一个 mixin，它可以让我的模型很容易地转换成一个深层的值字典（有点像 .values()，但遍历关系）。对这些进行定义的最干净的地方似乎是模型本身，例如：
class Person(models.Model, DeepValues):
name = models.CharField(blank=True, max_length=100)
tribe = models.ForeignKey('Tribes')
class Meta:
schema = {
'name' : str,
'tribe' : {
'name' : str
}
}
Person.objects.all().deep_values() => {
'name' : 'Andrey Fedorov',
'tribe' : {
'name' : 'Mohicans'
}
}
However, Django complains about my including this in class Metawith:
但是，Django 抱怨我将其包含在class Meta：
TypeError: 'class Meta' got invalid attribute(s): schema
(entire stack trace here)
（此处为整个堆栈跟踪）
Now, I suppose I could elaborately override this in my mixin, but is there a more elegant way of storing this information?
现在，我想我可以在我的 mixin 中精心覆盖它，但是有没有更优雅的方式来存储这些信息？
回答by Vinay Sajip
I don't know about elegant, but one pragmatic way is:
我不知道优雅，但一种务实的方法是：
import django.db.models.options as options
options.DEFAULT_NAMES = options.DEFAULT_NAMES + ('schema',)
Obviously, this would break if Django ever added a 'schema' attribute of its own. But hey, it's a thought...you could always pick an attribute name which is less likely to clash.
显然，如果 Django 添加了它自己的“模式”属性，这将会中断。但是，嘿，这是一个想法......你总是可以选择一个不太可能发生冲突的属性名称。
