使用 ModelSerializer 序列化一对多关系

Question

我的目标是嵌套 JSON 响应。我的目标输出是这样的；

[
 {
   list_id: <list_id_1>,
   list_name: <list_name_1>,
    {
       item_id: <item_id_1>,
       item_name: <item_name_1>,
    },
    {
       item_id: <item_id_2>,
       item_name: <item_name_2>,
    }
 }
]

我想让我的输出成为一个嵌套的 JSON。到目前为止，这是我的进步；

models.py

class List(models.Model):
    list_name = models.CharField(max_length=30, blank=True, null=True, default='My List')

    def __str__(self):
        return ("List ID: " + str(self.id) + ", " + self.list_name)


class Item(models.Model):
    list = models.ForeignKey('List', related_name='items', on_delete=models.CASCADE)
    item_name = models.CharField(max_length=30, blank=False, null=False)
    item_desc = models.CharField(max_length=50, blank=True, null=True)
    item_category = models.CharField(max_length=20, blank=True, null=True)
    item_price = models.DecimalField(max_digits=5, decimal_places=2, blank=False, null=False, default=0.00)
    item_qty = models.IntegerField(blank=False, null=False, default=1)
    is_complete = models.BooleanField(default=False)

    def __str__(self):
        return ("Item ID: " + str(self.id) + ", " + self.item_name)

    @property
    def item_tot_price(self):
        return (self.item_price * self.item_qty)

序列化器.py

class ItemSerializer(serializers.ModelSerializer):
    list_name = serializers.CharField(read_only=True, source = "list.list_name")

    class Meta:
        model = models.Item
        fields = ['id', 'list', 'list_name', 'item_name', 'item_desc', 'item_category', 'item_price', 'item_qty', 'is_complete', 'item_tot_price']

views.py

class ItemListAPIView(generics.ListAPIView):
    serializer_class = serializers.ItemSerializer

    def get_queryset(self):
        """
        This APIView should return a list of all the items 
        that are related to a List as determined by the 
        list portion of the URL.
        """
        list = self.kwargs['list']
        return models.Item.objects.filter(list__id=list)

urls.py

urlpatterns = [
    path('Items/<int:list>/', views.ItemListAPIView.as_view()),
]

使用我当前进度的输出：

[
    {
        "item_id": 10,
        "list_id": 4,
        "list_name": "TestName",
        "item_name": "TestName",
        "item_desc": "TestName",
        "item_category": "TestName",
        "item_price": "2.00",
        "item_qty": 9,
        "is_complete": true,
        "item_tot_price": 18.0
    },
    {
        "item_id": 12,
        "list_id": 4,
        "list_name": "TestName",
        "item_name": "TestName",
        "item_desc": "TestName",
        "item_category": "TestName",
        "item_price": "0.00",
        "item_qty": 1,
        "is_complete": false,
        "item_tot_price": 0.0
    },

]

从我当前的输出 JSON 中可以看出，它会将项目排序到相应的列表中。但是我想将 list_id 和 list_name 显示为父项，然后显示项目的数据。

简单来说，我想做一个能够获取 list_id 并显示与列表相关的所有项目的端点。

免责声明：我使用 many=True agruments、related_fields、HyperlinkedModelSerializer 弄乱了序列化程序。它们都没有按我想要的方式工作。

Answer 1

编辑您的serializers.py，如下所示。不要序列化Item，而是使用List，所以在你的views.py中你将使用ListSerializer而不是ItemSerializer

class ItemSerializer(serializers.ModelSerializer):
    list_name = serializers.CharField(read_only=True, source = "list.list_name")

    class Meta:
        model = models.Item
        fields = ['id', 'list', 'list_name', 'item_name', 'item_desc', 'item_category', 'item_price', 'item_qty', 'is_complete', 'item_tot_price']

class ListSerializer(serializers.ModelSerializer):
    items = ItemSerializer(many=True, read_only=True)
    class Meta:
        model = List
        fields = ['id','list_name','items']

Answer 2

感谢@Yves Hary 和@adnan kaya，

根据 Yves 所说，我修改了我的 ListSerializer 以包含

items = ItemSerializer(many=True, read_only=True)

因此，

class ItemSerializer(serializers.ModelSerializer):
    list_name = serializers.CharField(read_only=True, source = "list.list_name")

    class Meta:
        model = models.Item
        fields = ['id', 'list', 'list_name', 'item_name', 'item_desc', 'item_category', 'item_price', 'item_qty', 'is_complete', 'item_tot_price']


class ListSerializer(serializers.ModelSerializer):
    """New Line Added Here"""
    items = ItemSerializer(many=True, read_only=True) 

    class Meta:
        model = models.List
        fields = ['id', 'list_name', 'items']

我之前做了调整，根据adnan给出的答案，确认方法是正确的。

使用当前的序列化程序，如果我使用 ModelViewSet，它将显示所有列表及其所有项目。像这样;

class ListViewSet(viewsets.ModelViewSet):
    queryset = models.List.objects.all()
    serializer_class = serializers.ListSerializer

我的目标是显示带有项目的特定列表。所以，我像这样使用 generics.ListAPIView 实现了一个视图；

class ListItemAPIView(generics.ListAPIView):
    serializer_class = serializers.ListSerializer

    def get_queryset(self):
        list = self.kwargs['list']
        return models.List.objects.filter(id=list)

最后，我的 urls.py 看起来像这样；

urlpatterns = [
    path('List/<int:list>/', views.ListItemAPIView.as_view()),
]

只有这样我的输出才会这样；

[
    {
        "list_id": <list_id>,
        "list_name": "<list_name>",
        "items": [
            {
                "item_id": <item_id>,
                "list_id": <list_id>,
                "list_name": "<list_name>",
                "item_name": "TestName",
                "item_desc": "TestName",
                "item_category": "TestName",
                "item_price": "2.00",
                "item_qty": 3,
                "is_complete": false,
                "item_tot_price": 6.0
            },
            {
                "item_id": <item_id>,
                "list_id": <list_id>,
                "list_name": "<list_name>",
                "item_name": "TestName",
                "item_desc": "TestName",
                "item_category": "TestName",
                "item_price": "2.00",
                "item_qty": 3,
                "is_complete": false,
                "item_tot_price": 6.0
            }
        ]
    }
]

编辑：封装 JSON 响应并添加关键字“lists”；

renderers.py

from rest_framework.renderers import JSONRenderer, BrowsableAPIRenderer


class BaseFlutterJSONRenderer(JSONRenderer):

    def render(self, data, accepted_media_type=None, renderer_context=None):
        data = {'lists': data}
        return super(BaseFlutterJSONRenderer, self).render(data, accepted_media_type, renderer_context)


class FlutterJSONRenderer(BrowsableAPIRenderer):
    def get_default_renderer(self, view):
        return BaseFlutterJSONRenderer()