Django 2.0，一级类视图，AttributeError：“str”对象没有属性“values”

Question

我在 Django 2.0 中创建了一个通用视图和序列化程序，因此我不必重复我自己，创建 CRUD 视图或序列化程序。

我的 API 应用程序的 views.py 文件

from rest_framework import generics, mixins
from rest_framework.serializers import ModelSerializer


class StandardListMixinCreateApiView(mixins.CreateModelMixin, generics.ListAPIView):
    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)


class StandardRudApiView(generics.RetrieveUpdateDestroyAPIView):
    lookup_field = 'pk'

此函数设置每个启用模型的serializer.Meta.model。 `cls 参数是 StandardApiViews 之一。

def get_adapted_class(cls, model_class, serializer_fields='__all__'):

    class AdaptedSerializer(ModelSerializer):
        class Meta:
            model = model_class

        fields = serializer_fields

    class AdaptedView(cls):
        model = model_class.__name__
        queryset = model_class.objects.all()
        serializer_class = AdaptedSerializer

    return AdaptedView

我的 urls.py

from django.urls import re_path
from .views import *
from django.contrib.auth.models import Group, Permission
from .models import *

app_name = "api"

为其生成 CRUD 视图的模型。

ENABLEDMODELS = [
    Address,
    Group,
    Permission,
    Customer,
    Employee,
    Commission,
    BugReport,
    FeatureRequest,
]

APILISTVIEWS = [get_adapted_class(
    StandardListMixinCreateApiView,
    model) for model in ENABLEDMODELS]

APIRUDVIEWS = [get_adapted_class(
    StandardRudApiView,
    model) for model in ENABLEDMODELS]

为每个创建的 ListView 添加一个 url 路由到 urlpatterns

# List, create views
urlpatterns = [re_path(
    f'^(?i){class_view.model}/',
    class_view.as_view(),
    name=f'{class_view.model}-list') for class_view in APILISTVIEWS]

# Retrive, update, delete views
urlpatterns += [re_path(
    f'^(?i){class_view.model}/' + r'(?P<pk>\d+)',
    class_view.as_view(),
    name=f'{class_view.model}-rud') for class_view in APIRUDVIEWS]

错误信息

Environment:


Request Method: GET
Request URL: http://localhost:8000/api/address/

Django Version: 2.0.4
Python Version: 3.6.5
Installed Applications:
['django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'rest_framework',
'api']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\handlers\exception.py" in inner
35.             response = get_response(request)

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\handlers\base.py" in _get_response
158.                 response = self.process_exception_by_middleware(e, request)

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\handlers\base.py" in _get_response
156.                 response = response.render()

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\django\template\response.py" in render
106.             self.content = self.rendered_content

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\response.py" in rendered_content
72.         ret = renderer.render(self.data, accepted_media_type, context)

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\renderers.py" in render
724.         context = self.get_context(data, accepted_media_type, renderer_context)

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\renderers.py" in get_context
656.         raw_data_post_form = self.get_raw_data_form(data, view, 'POST', request)

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\renderers.py" in get_raw_data_form
572.                 data = serializer.data.copy()

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\serializers.py" in data
560.         ret = super(Serializer, self).data

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\serializers.py" in data
266.                 self._data = self.get_initial()

File "C:\Users\Steffen22\AppData\Local\Programs\Python\Python36\lib\site-packages\rest_framework\serializers.py" in get_initial
413.             for field in self.fields.values()

Exception Type: AttributeError at /api/address/
Exception Value: 'str' object has no attribute 'values'

Answer 1

我找到了一个解决方案，可以重用我的标准 REST 视图、序列化程序并根据它们生成 url。

'api/views.py'

from rest_framework import generics, mixins
from rest_framework.serializers import ModelSerializer


class StandardListMixinCreateApiView(mixins.CreateModelMixin, generics.ListAPIView):
    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)


class StandardRudApiView(generics.RetrieveUpdateDestroyAPIView):
    lookup_field = 'pk'


def get_adapted_class(cls, model_class, serializer_fields='__all__'):
    class AdaptedView(cls):
        model = model_class.__name__

我不得不重写 get_serializer_class 函数，而不是设置 serializer_class 属性。

        def get_serializer_class(self):
            class BaseSerializer(ModelSerializer):
                class Meta:
                    model = model_class
                    fields = serializer_fields
            return BaseSerializer

        def get_queryset(self):
            return model_class.objects.all()

    return AdaptedView

那些标准的 ApiViews 好用，你可以新建一个 django 模型并将模型类添加到 ENABLEDMODELS 列表中

'api/urls.py'

from django.urls import re_path
from .views import *
from django.contrib.auth.models import Group, Permission
from .models import *

app_name = "api"

ENABLEDMODELS = [
    Address,
    Group,
    Permission,
    Customer,
    Employee,
    Commission,
    BugReport,
    FeatureRequest,
]

APILISTVIEWS = [get_adapted_class(
    StandardListMixinCreateApiView,
    model) for model in ENABLEDMODELS]

APIRUDVIEWS = [get_adapted_class(
    StandardRudApiView,
    model) for model in ENABLEDMODELS]

在 2.0 以下的 Django 版本中，path/re_path 方法称为 url，如果您更改它应该也可以在旧版本中使用。

re_path 方法用于 Django 2.0 中的正则表达式路由

# List, create views
urlpatterns = [re_path(
    f'^(?i){class_view.model}/',
    class_view.as_view(),
    name=f'{class_view.model}-list') for class_view in APILISTVIEWS]

# Retrive, update, delete views
urlpatterns += [re_path(
    f'^(?i){class_view.model}/' + r'(?P<pk>\d+)',
    class_view.as_view(),
    name=f'{class_view.model}-rud') for class_view in APIRUDVIEWS]