django - 如何使用 Django Rest Framework 创建多个模型实例？

Question

我想通过一个 API 调用使用 Django Rest Framework 保存和更新多个实例。例如，假设我有一个可以有多个“教师”的“教室”模型。如果我想创建多个教师，然后更新他们所有的教室号码，我会怎么做？我是否必须为每位教师进行 API 调用？

我知道目前我们无法保存嵌套模型，但我想知道我们是否可以在教师级别保存它。谢谢！

Answer 1

我知道这是不久前有人问过的，但是我在自己尝试解决这个问题时发现了它。

事实证明，如果您many=True在为模型实例化序列化程序类时通过，那么它可以接受多个对象。

这在 django rest 框架文档中提到这里

就我而言，我的观点是这样的：

class ThingViewSet(viewsets.ModelViewSet):
    """This view provides list, detail, create, retrieve, update
    and destroy actions for Things."""
    model = Thing
    serializer_class = ThingSerializer

我真的不想写一堆样板来直接控制序列化程序的实例化和 pass many=True，所以在我的序列化程序类中，我重写了__init__：

class ThingSerializer(serializers.ModelSerializer):
    def __init__(self, *args, **kwargs):
        many = kwargs.pop('many', True)
        super(ThingSerializer, self).__init__(many=many, *args, **kwargs)

    class Meta:
        model = Thing
        fields = ('loads', 'of', 'fields', )

以以下格式将数据发布到此视图的列表 URL：

[
    {'loads':'foo','of':'bar','fields':'buzz'},
    {'loads':'fizz','of':'bazz','fields':'errrrm'}
]

使用这些详细信息创建了两个资源。这很好。

Answer 2

我得出了与 Daniel Albarral 类似的结论，但这里有一个更简洁的解决方案：

class CreateListModelMixin(object):

    def get_serializer(self, *args, **kwargs):
        """ if an array is passed, set serializer to many """
        if isinstance(kwargs.get('data', {}), list):
            kwargs['many'] = True
        return super(CreateListModelMixin, self).get_serializer(*args, **kwargs)

Answer 3

这是另一种解决方案，您不需要覆盖您的序列化程序__init__方法。只需覆盖您的视图的 (ModelViewSet)'create'方法。注意many=isinstance(request.data,list)。在这里many=True，当您发送要创建的对象数组以及False仅发送一个对象时。这样，您可以同时保存项目和列表！

from rest_framework import status, viewsets
from rest_framework.response import Response

class ThingViewSet(viewsets.ModelViewSet):

"""This view snippet provides both list and item create functionality."""

    #I took the liberty to change the model to queryset
    queryset = Thing.objects.all()
    serializer_class = ThingSerializer

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data, many=isinstance(request.data,list))
        serializer.is_valid(raise_exception=True)
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)

Answer 4

我无法完全弄清楚如何让 request.DATA 从字典转换为数组——这限制了我使用 Tom Manterfield 的解决方案的能力。这是我的解决方案：

class ThingSerializer(serializers.ModelSerializer):
    def __init__(self, *args, **kwargs):
        many = kwargs.pop('many', True)
        super(ThingSerializer, self).__init__(many=many, *args, **kwargs)

    class Meta:
        model = Thing
        fields = ('loads', 'of', 'fields', )

class ThingViewSet(mixins.CreateModelMixin, viewsets.GenericViewSet ):
    queryset = myModels\
        .Thing\
        .objects\
        .all()
    serializer_class = ThingSerializer

    def create(self, request, *args, **kwargs):
        self.user = request.user
        listOfThings = request.DATA['things']

        serializer = self.get_serializer(data=listOfThings, files=request.FILES, many=True)
        if serializer.is_valid():
            serializer.save()
            headers = self.get_success_headers(serializer.data)
            return Response(serializer.data, status=status.HTTP_201_CREATED,
                            headers=headers)

        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

然后我在客户端上运行这个等价物：

var things = {    
    "things":[
        {'loads':'foo','of':'bar','fields':'buzz'},
        {'loads':'fizz','of':'bazz','fields':'errrrm'}]
}
thingClientResource.post(things)

Answer 5

我认为尊重框架提议架构的最佳方法是创建一个像这样的 mixin：

class CreateListModelMixin(object):

    def create(self, request, *args, **kwargs):
        """
            Create a list of model instances if a list is provided or a
            single model instance otherwise.
        """
        data = request.data
        if isinstance(data, list):
            serializer = self.get_serializer(data=request.data, many=True)
        else:
            serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data, status=status.HTTP_201_CREATED,
                    headers=headers)

然后你可以像这样覆盖 ModelViewSet 的 CreateModelMixin ：

class <MyModel>ViewSet(CreateListModelMixin, viewsets.ModelViewSet):
    ...
    ...

现在在客户端你可以这样工作：

var things = [    
    {'loads':'foo','of':'bar','fields':'buzz'},
    {'loads':'fizz','of':'bazz','fields':'errrrm'}
]
thingClientResource.post(things)

或者

var thing = {
    'loads':'foo','of':'bar','fields':'buzz'
}
    
thingClientResource.post(thing)

编辑：

正如罗杰柯林斯在他的回应中建议的那样，覆盖 get_serializer 方法比“创建”更聪明。

Answer 6

您可以简单地覆盖get_serializerAPIView 中的方法并传入many=True基本get_serializer视图，如下所示：

class SomeAPIView(CreateAPIView):
    queryset = SomeModel.objects.all()
    serializer_class = SomeSerializer

    def get_serializer(self, instance=None, data=None, many=False, partial=False):
        return super(SomeAPIView, self).get_serializer(instance=instance, data=data, many=True, partial=partial)

Answer 7

我想出了一个简单的例子post

序列化程序.py

from rest_framework import serializers
from movie.models import Movie

class MovieSerializer(serializers.ModelSerializer):

    class Meta:
        model = Movie
        fields = [
            'popularity',
            'director',
            'genre',
            'imdb_score',
            'name',
        ]  

视图.py

from rest_framework.response import Response
from rest_framework import generics
from .serializers import MovieSerializer
from movie.models import Movie
from rest_framework import status
from rest_framework.permissions import IsAuthenticated

class MovieList(generics.ListCreateAPIView):
    queryset = Movie.objects.all().order_by('-id')[:10]
    serializer_class = MovieSerializer
    permission_classes = (IsAuthenticated,)

    def list(self, request):
        queryset = self.get_queryset()
        serializer = MovieSerializer(queryset, many=True)
        return Response(serializer.data)

    def post(self, request, format=None):
        data = request.data
        if isinstance(data, list):  # <- is the main logic
            serializer = self.get_serializer(data=request.data, many=True)
        else:
            serializer = self.get_serializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

这些行是多实例的实际逻辑-

data = request.data
if isinstance(data, list):  # <- is the main logic
      serializer = self.get_serializer(data=request.data, many=True)
else:
      serializer = self.get_serializer(data=request.data)

如果您对 many=True 感到困惑，请参阅此

当我们发送数据时，它会在里面list有点像这样 -

[
    {
        "popularity": 84.0,
        "director": "Stanley Kubrick",
        "genre": [
            1,
            6,
            10
        ],
        "imdb_score": 8.4,
        "name": "2001 : A Space Odyssey"
    },
    {
        "popularity": 84.0,
        "director": "Stanley Kubrick",
        "genre": [
            1,
            6,
            10
        ],
        "imdb_score": 8.4,
        "name": "2001 : A Space Odyssey"
    }
]

Answer 8

Django REST Framework 文档中的通用视图页面指出ListCreateAPIView通用视图“用于读写端点以表示模型实例的集合”。

这就是我开始寻找的地方（实际上我会去寻找，因为我们很快也会在我们的项目中需要这个功能）。

另请注意，Generic Views 页面上的示例恰好使用ListCreateAPIView.

Answer 9

我遇到的最直接的方法：

    def post(self, request, *args, **kwargs):
        serializer = ThatSerializer(data=request.data, many=isinstance(request.data, list))
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        else:
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)