Question

我正在为一个网站创建一个API，我有一个带有Books的表，另一个带有Hashtags（基本上是一个主题标签的目录，例如＆＃34; #going＆＃34;）和一个中间表建立Books和Hashtags之间的多对多关系。我的模特是：

# models.py
class Books(models.Model):
    id_books = models.AutoField(primary_key=True)
    title = models.CharField(max_length=150)

class Hashtags(models.Model):
    id_hashtags = models.AutoField(primary_key=True)
    hashtag = models.CharField(max_length=150)

class Books_Hashtags(models.Model):
    id_books_hashtags = models.AutoField(primary_key=True)
    id_books = models.ForeignKey(Books, on_delete=models.CASCADE)
    id_hashtags = models.ForeignKey(Hashtags, on_delete=models.CASCADE)
    class Meta:
        unique_together = ("id_books", "id_hashtags")

我希望有一个提供如下输出的API：

[
    {
        "id_books": 1,
        "title": "The Hobbit",
        "hashtags": [
            {
                "id_hashtags": 1,
                "hashtag": "fantasy"
            },
            {
                "id_hashtags": 2,
                "hashtag": "fiction"
            },
            {
                "id_hashtags": 3,
                "hashtag": "middle earth"
            },
        ]
    }
]

为此，我使用DRF序列化上述模型，遵循我在网上找到的一些例子：

#serializers.py
from rest_framework import serializers
from app.models import Books, Books_Hashtags, Hashtags

class HashtagsSerializer(serializers.ModelSerializer):
    hashtags = serializers.CharField()
    class Meta:
        model = Hashtags
        fields = ('hashtag',)

class Books_HashtagsSerializer(serializers.ModelSerializer):
    id_hashtag = HashtagsSerializer(many=True, read_only=True)
    class Meta:
        model = Books_Hashtags
        fields = ('id_hashtags',)

class BooksSerializer(serializers.ModelSerializer):
    id_books = serializers.IntegerField()
    id_books_hashtags = Books_HashtagsSerializer(many=True, read_only=True)
    title = serializers.CharField()

    class Meta:
        model = Books
        fields = ('id_books', 'title', 'id_books_hashtags',)

我的观点如下：

#views.py
from ntgBackend.models import Books
from rest_framework import viewsets
from api.serializers import BooksSerializer

class BooksViewSet(viewsets.ModelViewSet):
    serializer_class = BooksSerializer
    queryset = Books.objects.all()

到目前为止，我已成功从API中获取以下输出：

[
    {
        "id_books": 1,
        "title": "The Hobbit",
    }
]

但是没有关于主题标签的信息，我知道它们存在于数据库中。我使用DRF 3.8.2和MySQL DB以及Django 2.0.2。请帮忙！

Answer 1

我遇到了同样的问题，并进行了一些研究：

在models.py中，仅使用Books_Hashtagas作为中间表，修改Book模型，使其包含带有Hashtags的ManyToManyField。另外，请务必在第一本书之前声明您的Hashtag模型，以供参考

# models.py
class Books(models.Model):
    id_books = models.AutoField(primary_key=True)
    title = models.CharField(max_length=150)
    hashtags = models.ManyToManyField(Hashtags, related_name='hashTg', through="Books_Hashtags"

在序列化程序文件中，请确保添加depth = 1以获取所需的内容，否则，您只会获得井号标签ID（仅适用于ListAPI）

#serializers.py
class BooksSerializer(serializers.ModelSerializer):
    class Meta:
        model = Books
        #In case you want to filter out some fields:
        #fields = ('field_A','field_B' )
        fields = '__all__'
        depth = 1

在视图中我使用泛型，因为它们可以满足我的大多数需求：

#views.py
from ntgBackend.models import Books
from rest_framework import generics
from api.serializers import BooksSerializer

class BooksViewSet(generics.ListCreateAPIView):
    serializer_class = BooksSerializer
    queryset = Books.objects.all()

我对此很陌生，希望对您有所帮助。除了Django（2.0.4），我使用的版本几乎与您相同。

祝你好运

Django REST框架 - 序列化多对多表关系

1 个答案: