Question

鉴于以下代码，我想以一种可以将字符串传递给EnumField构造函数的方式修改MyClass，并且它们会立即自动更新为枚举。我想过要覆盖＆＃34; setter＆＃34;，但是却无法在peewee的代码中找到它。

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，您看起来缺少的方法是coerce：

裹胁（值）

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

我会coerce与python_value相同：

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

如何覆盖＆＃34; setter＆＃34;在peewee领域？

1 个答案: