如何使 rest_framework Serializer 禁止多余的字段? [英] How to make a rest_framework Serializer disallow superfluous fields?

问题描述

我注意到 Serializer 在拒绝带有未知字段的输入时并不是很严格:

I've noticed that the Serializer isn't really strict when it comes to rejecting input with unknown fields:

In [1]: from rest_framework import serializers

In [2]: class TestSerializer(serializers.Serializer):
   ...:     foo = serializers.CharField()
   ...:     

In [3]: s = TestSerializer(data=dict(foo='foo', bar='bar'))

In [4]: s.is_valid()
Out[4]: True

有没有办法配置 Serializer 以返回有关 bar 在这种情况下意外的验证错误?

Is there a way to configure the Serializer to return a validation error about bar being unexpected in this situation?

推荐答案

这绝对有效:

class TestSerializer(serializers.Serializer):
    foo = serializers.CharField()

    def validate(self, attrs):
        unknown =  set(self.initial_data) - set(self.fields)
        if unknown:
            raise ValidationError("Unknown field(s): {}".format(", ".join(unknown)))
        return attrs

嵌套和列表序列化器

如果您使用这样的序列化程序作为另一个序列化程序中的字段，这将不起作用.在这种情况下，子序列化程序将无法访问初始数据，您将收到异常.

This will not work if you use a such a serializer as a field in another serializer. In which case, the child serializer won't have access to initial data and you will get an exception.

与 ListSerializer(或 many=True)相同，因为列表序列化器的子序列化器不会获得单独的 initial_data 项(有是 github ticket.

Same with a ListSerializer (or many=True) as the list serializer's child serializer won't get the individual initial_data items (there is a github ticket for this).

在那种情况下，适用于所有两种情况的稍微不太干净的解决方案是:

In that case the slightly less clean solution which works all both cases is:

from rest_framework.fields import empty
from rest_framework.settings import api_settings

class TestSerializer(serializers.Serializer):
    foo = serializers.CharField()

    def run_validation(self, data=empty):
        if data is not empty:
            unknown = set(data) - set(self.fields)
            if unknown:
                errors = ["Unknown field: {}".format(f) for f in unknown]
                raise serializers.ValidationError({
                    api_settings.NON_FIELD_ERRORS_KEY: errors,
                })

        return super(TestSerializer, self).run_validation(data)

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