如何覆盖peewee字段中的“setter”？

Question

给定下面的代码，我想修改EnumField，这样我就可以将字符串传递到MyClass构造函数中，然后立即自动将它们转换为enum。我想重写“setter”，但在peewee的代码中找不到它。在

from enum import Enum
from peewee import CharField, Model


class EnumField(CharField):
    "Custom field to support enums"

    def __init__(self, enum, **kwargs):
        super(EnumField, self).__init__(**kwargs)
        self.enum = enum

    def db_value(self, value):
        if isinstance(value, Enum):
            return str(value.name)  # convert enum to str
        elif isinstance(value, basestring):
            return value
        return None

    def python_value(self, value):
        if value:
            return self.enum[value]  # convert str to enum
        return None

    def clone_base(self, **kwargs):
        return super(EnumField, self).clone_base(enum=self.enum, **kwargs)


class FooEnum(Enum):
    FOO = "foo"
    BAR = "bar"


class MyClass(Model):
    field1 = EnumField(FooEnum)


my_class = MyClass(field1='foo')
type(my_class.field1) == FooEnum  # False, it's str but I would like it to be autocasted

my_class.save()
my_class = MyClass.get()
type(my_class.field1) == FooEnum  # True

Answer 1

根据Peewee docs for fields，您缺少的方法似乎是coerce：

coerce(value)

This method is a shorthand that is used, by default, by both db_value and python_value. You can usually get away with just implementing this.

Parameters:  value – arbitrary data from app or backend
Return type: python data type

我将使coerce与{}相同：

def python_value(self, value):
    if value:
        return self.enum[value]  # convert str to enum
    return None
coerce = python_value