16

我正在使用 Django-rest-framework 开发 API 并从 Web 应用程序中使用它。它有一个医师模型和一个来自 django.auth 用户模型的 Fk。我想从表单发布到医师模型，但序列化程序返回此消息：

{"user":{"non_field_errors":["无效数据。需要字典，但得到 unicode。"]}}

我正在发送用户对象的主键。在 DRF 上存储外键是正确的（或只是一种方式）。我尝试在序列化程序上覆盖 get_validation_exclusions 并在视图集上覆盖 perform_create 方法。

api 和 web 应用程序是分离的。该 API 是用 django 开发的，而 web 应用程序是用 angularjs 开发的。

我的模型

class Physician(models.Model):
    medical_office_number = models.CharField(max_length = 15)
    fiscal_id_number = models.CharField(max_length = 20)
    user = models.OneToOneField(User)

    def __unicode__(self):
        return self.user.first_name +' '+ self.user.last_name

序列化器：

class PhysicianSerializer(serializers.ModelSerializer):
    user = AccountSerializer()
    class Meta:
        model = Physician
        fields = ('id', 'user', 'medical_office_number', 'fiscal_id_number')
        read_only_fields = ('id')
        depth = 1
    def get_validation_exclusions(self, *args, **kwargs):
        exclusions = super(PhysicianSerializer, self).get_validation_exclusions()
        return exclusions + ['user']

*编辑这是我的帐户序列化程序，它基于此实现和@Kevin Brown 的建议

class PrimaryKeyNestedMixin(serializers.RelatedField, serializers.ModelSerializer):

    def to_internal_value(self, data):
        return serializers.PrimaryKeyRelatedField.to_internal_value(self, data)
    def to_representation(self, data):
        return serializers.ModelSerializer.to_representation(self, data)

class AccountSerializer(PrimaryKeyNestedMixin):
    password = serializers.CharField(write_only=True, required=False)
    confirm_password = serializers.CharField(write_only=True, required=False)

    class Meta:
        model = Account
        fields = ('id', 'email', 'username', 'created_at', 'updated_at',
                  'first_name', 'last_name', 'password',
                  'confirm_password', 'is_admin',)
        read_only_fields = ('created_at', 'updated_at',)

视图集

class AccountViewSet(viewsets.ModelViewSet):
    lookup_field = 'username'
    queryset = Account.objects.all()
    serializer_class = AccountSerializer

当我尝试序列化这个对象时，它会触发一个错误。

所以我可以从<select>元素中发布任何用户。但我无法验证解决方案。我错过了什么？

错误堆栈跟踪

TypeError at /api/v1/accounts/

__init__() takes exactly 1 argument (5 given)

Exception Location:     /home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/relations.py in many_init, line 68
Python Executable:  /home/jlromeroc/workspace/asclepios/venv/bin/python
Python Version:     2.7.3

File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response 111. response = wrapped_callback(request, *callback_args, **callback_kwargs) File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/django/views/decorators/csrf.py" in wrapped_view 57. return view_func(*args, **kwargs)
File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/viewsets.py" in view 85. return self.dispatch(request, *args, **kwargs)
File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/views.py" in dispatch 407. response = self.handle_exception(exc) File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/views.py" in dispatch 404. response = handler(request, *args, **kwargs)
File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/mixins.py" in list 45. serializer = self.get_serializer(instance, many=True)
File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/generics.py" in get_serializer 90. instance, data=data, many=many, partial=partial, context=context File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/relations.py" in __new__ 48. return cls.many_init(*args, **kwargs)
File "/home/jlromeroc/workspace/asclepios/venv/local/lib/python2.7/site-packages/rest_framework/relations.py" in many_init 68. list_kwargs = {'child_relation': cls(*args, **kwargs)}

Exception Type: TypeError at /api/v1/accounts/
Exception Value: __init__() takes exactly 1 argument (5 given)

编辑** 我已选择覆盖视图集上的创建函数并将对象包含在请求中，因此可以对其进行验证，但是随后，序列化程序会尝试为 Account 模型插入一个新对象。我怎样才能防止这种行为？我试图将 PhysicianSerializer 类上的序列化程序设置为 read_only 但随后，django 尝试使用 null user_id 存储模型。如何在不尝试插入相关对象的情况下保存模型？

4

5 回答 5

3

这里的问题是，对于嵌套序列化程序，Django REST 框架期望输入和输出都是嵌套表示。DRF 将自动验证输入以确保它与嵌套序列化程序匹配，从而允许您在单个请求中创建主对象和任何关系。

您正在寻找带有PrimaryKeyRelatedField输入的嵌套输出。这对于那些不需要在同一个请求中创建关系但总是在他们的关系中使用现有对象的人来说是很常见的。您将不得不这样做的方式基本上PrimaryKeyRelatedField是to_internal_value在to_representation. 像这样的东西（未经测试）应该可以工作

class PrimaryKeyNestedMixin(serializers.PrimaryKeyRelatedField, serializers.ModelSerializer):

    def to_internal_value(self, data):
        return serializers.PrimaryKeyRelatedField.to_internal_value(self, data)

    def to_representation(self, data):
        return serializers.ModelSerializer.to_representation(self, data)

在您的情况下，您需要将其用作嵌套序列化程序上的 mixin AccountSerializer，它应该可以满足您的需求。

于 2015-01-19T00:32:39.183 回答
3

我遇到了类似的问题（想要 POST 对象的 id / FK，但期望 GET 中的序列化对象）。我为我的案例成功实施了Kevin Brown 的解决方案。使其适应您的问题（为时已晚，但希望其他人，包括未来的我，偶然发现它并发现它有用）。

def get_primary_key_related_model(model_class, **kwargs):
    """
    Nested serializers are a mess. https://stackoverflow.com/a/28016439/2689986
    This lets us accept ids when saving / updating instead of nested objects.
    Representation would be into an object (depending on model_class).
    """
    class PrimaryKeyNestedMixin(model_class):

        def to_internal_value(self, data):
            try:
                return model_class.Meta.model.objects.get(pk=data)
            except model_class.Meta.model.DoesNotExist:
                self.fail('does_not_exist', pk_value=data)
            except (TypeError, ValueError):
                self.fail('incorrect_type', data_type=type(data).__name__)

        def to_representation(self, data):
            return model_class.to_representation(self, data)

    return PrimaryKeyNestedMixin(**kwargs)


class AccountSerializer(serializers.ModelSerializer):
    password = serializers.CharField(write_only=True, required=False)
    confirm_password = serializers.CharField(write_only=True, required=False)

    class Meta:
        model = Account
        # ...


class PhysicianSerializer(serializers.ModelSerializer):
    user = get_primary_key_related_model(AccountSerializer)

    class Meta:
        model = Physician
        # ...

当class您有自定义序列化程序字段（基于 request.user 限制访问）时，生成器非常方便。

于 2017-05-02T16:28:41.930 回答
1

我遵循了这个答案。禁用在 django rest 框架中创建嵌套对象它有点乱，但可以。无论哪种方式，这都是它缺乏 DRF 的东西。

于 2015-01-23T00:24:52.310 回答
0

我通过使用不同的视图来处理获取单个项目和帖子以及获取嵌套列表来解决这个问题。获取单个项目和获取列表使用嵌套序列化程序，而 post 方法使用非嵌套序列化程序。发布以创建新的工作提醒时，您可以使用工作的主键和作为相关对象的用户。

class JobAlertList(APIView):
    """
    List all job alerts or create a new job alert
    """
    def get(self, request, format=None):
        job_alerts = JobAlert.objects.all()
        serializer = JobAlertNestedSerializer(job_alerts, many=True)
        return Response(serializer.data)

    def post(self, request, format=None):
        serializer = JobAlertSerializer(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)


class JobAlertDetail(APIView):
    """
    Retrieve or delete a job alert instance.
    """
    def get_object(self, pk):
        try:
            return JobAlert.objects.get(pk=pk)
        except JobAlert.DoesNotExist:
            raise Http404

    def get(self, request, pk, format=None):
        job_alert = self.get_object(pk)
        serializer = JobAlertNestedSerializer(job_alert)
        return Response(serializer.data)

    def delete(self, request, pk, format=None):
        job_alert = self.get_object(pk)
        job_alert.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

class JobAlertSerializer(serializers.ModelSerializer):

    class Meta:
        model = JobAlert
        fields = ('job', 'user')
        depth = 0

    def create(self, validated_data):
        user = validated_data.pop('user')
        job = validated_data.pop('job')
        job_alert = JobAlert.objects.create(user=user, job=job)
        return job_alert


class JobAlertNestedSerializer(serializers.ModelSerializer):

    class Meta:
        model = JobAlert
        fields = ('id', 'job', 'user')
        depth = 1

url(r'^job_alerts/$', views.JobAlertList.as_view(), name='job-alerts-list'),
url(r'^job_alerts/(?P<pk>[0-9]+)/$', views.JobAlertDetail.as_view(), name='job-alerts-detail'),
于 2016-05-19T10:53:11.377 回答
0

我创建了一个 Field 类型，它试图用 Integer 中的 ForeignKey 解决 Data Save 请求的问题，以及使用嵌套数据读取数据的请求

这是课程：

class NestedRelatedField(serializers.PrimaryKeyRelatedField):
"""
    Model identical to PrimaryKeyRelatedField but its
    representation will be nested and its input will
    be a primary key.
"""

def __init__(self, **kwargs):
    self.pk_field = kwargs.pop('pk_field', None)
    self.model = kwargs.pop('model', None)
    self.serializer_class = kwargs.pop('serializer_class', None)
    super().__init__(**kwargs)

def to_representation(self, data):
    pk = super(NestedRelatedField, self).to_representation(data)
    try:
        return self.serializer_class(self.model.objects.get(pk=pk)).data
    except self.model.DoesNotExist:
        return None

def to_internal_value(self, data):
    return serializers.PrimaryKeyRelatedField.to_internal_value(self, data)

所以它会被使用：

class PostModelSerializer(serializers.ModelSerializer):

    message = NestedRelatedField(
         queryset=MessagePrefix.objects.all(),
         model=MessagePrefix,
         serializer_class=MessagePrefixModelSerializer
   )

我希望这可以帮助你。

于 2019-10-22T12:01:43.607 回答