Question

我有一个父棉花糖架构“ ParentSchema”和2个嵌套子架构“ ChildSchema1”和“ ChildSchema2”。两种嵌套子模式都利用@validates_schema装饰器从棉花糖进行字段验证。他们看起来像这样：

ParenSchema.py

from marshmallow import Schema, fields
from schemas.childSchema1 import ChildSchema1
from schemas.childSchema2 import ChildSchema2

    class ParentSchema(Schema):
        child1 = fields.Nested(ChildSchema1)
        child2 = fields.Nested(ChildSchema2)
        foo = fields.String()
        bar = fields.String()

ChildSchema1.py

from marshmallow import Schema, pprint, post_load
from marshmallow import fields, ValidationError, validates, validates_schema

class ChildSchema1(Schema):
    field1 = fields.String()
    field2 = fields.String()
    common_field = fields.String()

    @validates("common_field")
    def validate_common_field(self, common_field):
        try:
            # Validation logic
        except:
            raise ValidationError('common_field is not valid')

ChildSchema2.py

from marshmallow import Schema, pprint, post_load
from marshmallow import fields, ValidationError, validates, validates_schema

class ChildSchema2(Schema):
    common_field = fields.String()
    field3 = fields.String()

    @validates("common_field")
    def validate_common_field(self, common_field):
        try:
            # Exact Same Validation logic as common_field from ChildSchema1
        except:
            raise ValidationError('common_field is not valid')

鉴于ChildSchema1和ChildSchema2都具有相同名称的字段，并且具有相同的验证函数，我很乐意遵循DRY Principle并将该函数拉到ParentSchema.py。

Answer 1

我发现一个解决方案是创建一个单独的类来托管共享验证功能：

def validate_common_field(self, common_field):
    try:
        # Exact Same Validation logic as common_field from ChildSchema1
    except:
        raise ValidationError('common_field is not valid')

并通过删除@validates装饰器并在架构字段中使用validate参数来从ChildSchema1和ChildSchema2中使用它。

ChildSchema1.py

from marshmallow import Schema, pprint, post_load
from marshmallow import fields, ValidationError, validates, validates_schema
from validators import *

class ChildSchema1(Schema):
    field1 = fields.String()
    field2 = fields.String()
    common_field = fields.String(validate=validate_common_field)

validators.py 从棉花糖导入ValidationError，进行验证

def validate_common_field(self, common_field):
        try:
            # Validation logic
        except:
            raise ValidationError('common_field is not valid')

Answer 2

您可以使用具有单独功能的方法。

如果两个孩子都共享公共字段，则还可以使用继承来反映这一点，并分解该字段和逻辑。

class ChildSchema(Schema):
    common_field = fields.String()

    @validates("common_field")
    def validate_common_field(self, common_field):
        try:
            # Validation logic
        except:
            raise ValidationError('common_field is not valid')

class ChildSchema1(ChildSchema):
    field1 = fields.String()
    field2 = fields.String()

class ChildSchema2(ChildSchema):
    field3 = fields.String()

棉花糖父模式-如何在子模式之间共享验证装饰器？

2 个答案: