Django rest framework で formset みたいに一括で登録する

2020-10-15 2023-05-02 9分52秒

DRFで実装したAPIで、ManyToManyなフィールドに、同時にオブジェクトをCreate出来るようにしたい。

公式ドキュメントのやり方は少々煩雑なのでライブラリを使う

Contents

1 drf-writable-nested
2 注意点

drf-writable-nested

https://github.com/beda-software/drf-writable-nested

以下の使い方はドキュメントからの抜粋

Model

# models.py
from django.db import models


class Site(models.Model):
    url = models.CharField(max_length=100)


class User(models.Model):
    username = models.CharField(max_length=100)


class AccessKey(models.Model):
    key = models.CharField(max_length=100)


class Profile(models.Model):
    sites = models.ManyToManyField(Site)
    user = models.OneToOneField(User)
    access_key = models.ForeignKey(AccessKey, null=True)


class Avatar(models.Model):
    image = models.CharField(max_length=100)
    profile = models.ForeignKey(Profile, related_name='avatars')

Serializer

Serializerはこう書く。ManyToManyを定義してあるModelのSerializerでWritableNestedModelSerializerを継承する。OneToOneなフィールドにも対応している。

# serializers.py
from rest_framework import serializers
from drf_writable_nested.serializers import WritableNestedModelSerializer

class AvatarSerializer(serializers.ModelSerializer):
    image = serializers.CharField()

    class Meta:
        model = Avatar
        fields = ('pk', 'image',)

class SiteSerializer(serializers.ModelSerializer):
    url = serializers.CharField()

    class Meta:
        model = Site
        fields = ('pk', 'url',)

class AccessKeySerializer(serializers.ModelSerializer):

    class Meta:
        model = AccessKey
        fields = ('pk', 'key',)


class ProfileSerializer(WritableNestedModelSerializer):
    # Direct ManyToMany relation
    sites = SiteSerializer(many=True)

    # Reverse FK relation
    avatars = AvatarSerializer(many=True)

    # Direct FK relation
    access_key = AccessKeySerializer(allow_null=True)

    class Meta:
        model = Profile
        fields = ('pk', 'sites', 'avatars', 'access_key',)


class UserSerializer(WritableNestedModelSerializer):
    # Reverse OneToOne relation
    profile = ProfileSerializer()

    class Meta:
        model = User
        fields = ('pk', 'profile', 'username',)

登録処理

data = {
    'username': 'test',
    'profile': {
        'access_key': {
            'key': 'key',
        },
        'sites': [
            {
                'url': 'http://google.com',
            },
            {
                'url': 'http://yahoo.com',
            },
        ],
        'avatars': [
            {
                'image': 'image-1.png',
            },
            {
                'image': 'image-2.png',
            },
        ],
    },
}

user_serializer = UserSerializer(data=data)
user_serializer.is_valid(raise_exception=True)
user = user_serializer.save()

# 確認してみる
user_serializer = UserSerializer(instance=user)
print(user_serializer.data)

#>> 結果
{
    'pk': 1,
    'username': 'test',
    'profile': {
        'pk': 1,
        'access_key': {
            'pk': 1,
            'key': 'key'
        },
        'sites': [
            {
                'pk': 1,
                'url': 'http://google.com',
            },
            {
                'pk': 2,
                'url': 'http://yahoo.com',
            },
        ],
        'avatars': [
            {
                'pk': 1,
                'image': 'image-1.png',
            },
            {
                'pk': 2,
                'image': 'image-2.png',
            },
        ],
    },
}