django-rest-framework 多对多关系。如果不存在则创建

Question

我尝试将以下数据发送到我的 Django 应用程序：

{
    "hashtags": ["hashtag"], 
    "title": "title", 
    "message": "message"
}

我收到了这样的回复：

{
    "hashtags": [
        {
            "non_field_errors": [
                "Invalid data. Expected a dictionary, but got int."
            ]
        }
    ]
}

我在 views.py

中定义了以下视图

class PostList(generics.ListCreateAPIView):
    queryset = Post.objects.all()
    serializer_class = PostSerializer
    permission_classes = IsAuthorizedOwnerOrReadOnly,

模型定义如下：

class Post(models.Model):
    ambassador = models.OneToOneField("User")
    publish_date = models.DateTimeField(auto_now_add=True, null=True, blank=True)
    hashtags = models.ManyToManyField("PostHashtags", related_query_name="posts")

    title = models.CharField(max_length=TEXT_SHORT, null=True, blank=True)
    message = models.CharField(max_length=TEXT_MIDDLE, null=True, blank=True)


class PostHashtags(models.Model):
    hashtag = models.CharField(max_length=TEXT_SHORT, null=False)

    def __unicode__(self):
        return self.hashtag

我这样定义序列化程序：

class PostHashtagSerializer(serializers.ModelSerializer):

    class Meta:
        model = PostHashtags
        fields = ("hashtag",)


class PostSerializer(serializers.ModelSerializer):
    hashtags = PostHashtagSerializer(many=True)
    class Meta:
        model = Post
        fields = ("id", "hashtags", "title", "message",)
        read_only_fields = ("id", 'account_name',)

主题标签似乎不是使用我当前的序列化配置自动创建的。如果我的 hashtags 尚不存在，有没有办法创建它们？如果它们存在，让 Post 使用相同的标签？在那种情况下，我的序列化程序应该如何定义？

编辑 1： 在 GwynBleidD 的建议之后，我现在收到以下错误：

The `.create()` method does not support writable nestedfields by default.
Write an explicit `.create()` method for serializer PostSerializer , or set `read_only=True` on nested serializer fields.

有人对这种创建方法有什么建议吗？

编辑 2: 使用以下序列化器解决了它

class PostHashtagSerializer(serializers.ModelSerializer):
    hashtag = serializers.CharField()
    class Meta:
        model = PostHashtags
        fields = ("hashtag",)


class PostSerializer(serializers.ModelSerializer):
    hashtags = PostHashtagSerializer(many=True,)

    class Meta:
        model = Post
        fields = ("ambassador", "hashtags", "title", "message",)

    def create(self, validated_data):
        hashtags_data = validated_data.pop('hashtags')

        post = Post.objects.create(**validated_data)
        for hashtag in hashtags_data:
            ht = PostHashtags.objects.create()
            ht.hashtag = hashtag.get("hashtag")
            ht.save()
            post.hashtags.add(ht)
        post.save()
        return post

Answer 1

在那个例子中，标签不是字符串，而是字典。您必须提交：

{
    "hashtags": [{"hashtag": "hashtag"}], 
    "title": "title", 
    "message": "message"
}

django-rest-framework 多对多关系。如果不存在则创建

django-rest-framework many-to-many relations. Create if not exists

python

django

django-rest-framework