类型为ManyToManyField的字段在发送请求时不保存数据。

Question

基本上，我做的事情就像‘我们自己的存档’，我没有保存或保存工作，但是ManyToMany字段数据没有保存

views.py

if request.method == 'POST':  
    serializer = FanficSerializerCreate(data=request.data)

    if serializer.is_valid():
      serializer.save()
      return Response({'fanfic': serializer.data}, status = status.HTTP_201_CREATED)

models.py

class Fanfic(models.Model):
...
  user = models.ForeignKey(User, on_delete=models.CASCADE)
  title = models.CharField(max_length=200)
  fandoms = models.ManyToManyField(Fandom)
  pairings = models.ManyToManyField(Pairing)
  characters = models.ManyToManyField(Hero)
  tags = models.ManyToManyField(Tag)
....

serializer.py

class FanficSerializerCreate(ModelSerializer):

  fandoms = FandomSerializer(many=True, read_only=True)
  pairings = PairingSerializer(many=True, read_only=True)
  characters = HeroSerializer(many=True, read_only=True)
  tags = TagSerializer(many=True, read_only=True)

  class Meta:
    model = Fanfic
    fields = ['id', 'user', 'title', 'fandoms', 'pairings', 'characters', 'translate', 'categories', 'end', 'relationships', 'tags', 'description', 'note', 'i_write_for', 'created', 'updated']

我认为问题是在另一节的序列化程序中，例如，添加一个具有相同视图代码的字符，但是模型中没有多个manytomanyfield字段就可以了。

当我在serializers.py中写这个的时候

fandoms = FandomSerializer(many=True, read_only=True)
  pairings = PairingSerializer(many=True, read_only=True)
  characters = HeroSerializer(many=True, read_only=True)
  tags = TagSerializer(many=True, read_only=True)

显示

{
   "fanfic": {
      "id": 4,
      "user": 3,
      "title": "Claimed",
      "fandoms": [],
      "pairings": [],
      "characters": [],
      "translate": "NO",
      "categories": "M",
      "end": "ENDED",
      "relationships": "M/M",
      "tags": [],
      "description": "",
      "i_write_for": "...",
      "created": "2022-11-14T13:46:44.425693Z",
      "updated": "2022-11-14T13:46:44.425693Z"
   }
}

id只是没有添加到字段中。

当我在serializers.py中写这个的时候

fandoms = FandomSerializer(many=True)
  pairings = PairingSerializer(many=True)
  characters = HeroSerializer(many=True)
  tags = TagSerializer(many=True)

邮递员

{
   "message": {
      "fandoms": [
         "This field is required."
      ],
      "pairings": [
         "This field is required."
      ],
      "characters": [
         "This field is required."
      ],
      "tags": [
         "This field is required."
      ]
   }
}

Answer 1

可以将嵌套序列化器的字段设置为required=False对该字段不需要的字段：

class FanficSerializerCreate(ModelSerializer):

  fandoms = FandomSerializer(many=True, required=False)
  ...

  class Meta:
    model = Fanfic
    ...

此外，您还可以为Meta类中的不同字段使用它：

class FanficSerializerCreate(ModelSerializer):

  fandoms = FandomSerializer(many=True)
  ...

  class Meta:
    model = Fanfic
    extra_kwargs = {
        'fandoms': {'required': False}
        ...
    }
    ...

参考资料：(https://www.django-rest-framework.org/api-guide/fields/#required)