Django Rest Framework中的to_representation（）可以访问正常字段 [英] Can to_representation() in Django Rest Framework access the normal fields

问题描述

使用 to_representation 的文档有些短。此方法由 Django Rest Framework 3.0 + 用于更改API中数据的表示。

The docs on using to_representation is somewhat short. This method is used by Django Rest Framework 3.0+ to change the representation of your data in an API.

此处'文档链接：

http://www.django-rest-framework.org/api-guide/serializers/#overriding-serialization-and-deserialization-behavior

这是我现在的代码：

from django.forms.models import model_to_dict

class PersonListSerializer(serializers.ModelSerializer):

    class Meta:
        model = Person
        fields = ('foo', 'bar',)

    def to_representation(self, instance):
        return model_to_dict(instance)

当我执行此代码时，它会返回模型中的所有字段，而不是以上指定的字段类Meta：fields 。

When I do this code, it returns all fields in the model instead of the fields that I have specified above in class Meta: fields.

可以在 to_representation 类Meta：fields $ c>方法？

Is it possible to reference the class Meta: fields within the to_representation method?

推荐答案

DRF的 ModelSerializer 已经具有所有逻辑来处理。在您的情况下，您甚至不需要自定义 to_representation 。如果你需要定制它，我建议先调用super，然后自定义输出：

DRF's ModelSerializer already has all the logic to handle that. In your case you shouldn't even need to customize to_representation. If you need to customize it, I would recommend to first call super and then customize the output:

class PersonListSerializer(serializers.ModelSerializer):
    class Meta:
        model = Person
        fields = ('foo', 'bar',)

    def to_representation(self, instance):
        data = super(PersonListSerializer, self).to_representation(instance)
        data.update(...)
        return data

---

PS如果你有兴趣知道它是如何工作的，魔术实际上并不会发生在 ModelSerializer.to_representation 中。事实上，它甚至没有实现这种方法。它通常在 串行 。 Django的所有魔力都会发生在 get_fields ，调用 get_field_names ，然后再考虑 Meta.fields 参数...

---

P.S. if you are interested to know how it works, the magic actually does not happen in ModelSerializer.to_representation. As a matter of fact, it does not even implement that method. Its implemented on regular Serializer. All the magic with Django models actually happens in get_fields which calls get_field_names which then considers the Meta.fields parameters...

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