长话短说

我正在寻找一种方法来在请求后清除缓存，或者在运行测试时完全禁用它。Django REST Framework 似乎缓存了结果，我需要一种解决方法。 p>

长版本和代码

好吧，当我不断测试它时，它表现得非常奇怪。最后，我让它工作了，但我真的不喜欢我的解决方法，以知识的名义，我必须找出为什么会发生这种情况以及如何正确解决这个问题。

所以，我有一个 APITestCase类声明如下:

class UserTests(APITestCase):

在这个类中，我有一个用于我的 user-list View 的测试函数，因为我有一个取决于权限的自定义查询集。清理问题:

super 用户可以获得整个用户列表(返回 4 个实例)，
工作人员看不到 super 用户(返回 3 个实例)，
普通用户只能得到 1 个结果，他们自己的用户(返回 1 个实例)

有效的测试函数版本:

def test_user_querysets(self):

    url = reverse('user-list')

    # Creating a user
    user = User(username='user', password=self.password)
    user.set_password(self.password)
    user.save()

    # Creating a second user
    user2 = User(username='user2', password=self.password)
    user2.set_password(self.password)
    user2.save()

    # Creating a staff user
    staff_user = User(username='staff_user', password=self.password, is_staff=True)
    staff_user.set_password(self.password)
    staff_user.save()

    # Creating a superuser
    superuser = User(username='superuser', password=self.password, is_staff=True, is_superuser=True)
    superuser.set_password(self.password)
    superuser.save()



    # SUPERUSER

    self.client.logout()
    self.client.login(username=superuser.username, password=self.password)

    response = self.client.get(url)

    # HTTP_200_OK
    self.assertEqual(response.status_code, status.HTTP_200_OK)

    # All users contained in list
    self.assertEqual(response.data['extras']['total_results'], 4)



    # STAFF USER

    self.client.logout()
    self.client.login(username=staff_user.username, password=self.password)

    response = self.client.get(url)

    # HTTP_200_OK
    self.assertEqual(response.status_code, status.HTTP_200_OK)

    # Superuser cannot be contained in list
    self.assertEqual(response.data['extras']['total_results'], 3)



    # REGULAR USER

    self.client.logout()
    self.client.login(username=user2.username, password=self.password)

    response = self.client.get(url)

    # HTTP_200_OK
    self.assertEqual(response.status_code, status.HTTP_200_OK)

    # Only 1 user can be returned
    self.assertEqual(response.data['extras']['total_results'], 1)

    # User returned is current user
    self.assertEqual(response.data['users'][0]['username'], user2.username)

如您所见，我按以下顺序测试用户权限: super 用户、员工、普通用户。这行得通，所以...

有趣的事情:

如果我改变测试顺序，从普通用户、员工、 super 用户开始，测试就会失败。第一个请求的响应被缓存，然后我以 staff 用户登录时得到相同的响应，所以结果数又是 1。

不起作用的版本:

和之前完全一样，只是测试的顺序相反

def test_user_querysets(self):

    url = reverse('user-list')

    # Creating a user
    user = User(username='user', password=self.password)
    user.set_password(self.password)
    user.save()

    # Creating a second user
    user2 = User(username='user2', password=self.password)
    user2.set_password(self.password)
    user2.save()

    # Creating a staff user
    staff_user = User(username='staff_user', password=self.password, is_staff=True)
    staff_user.set_password(self.password)
    staff_user.save()

    # Creating a superuser
    superuser = User(username='superuser', password=self.password, is_staff=True, is_superuser=True)
    superuser.set_password(self.password)
    superuser.save()



    # REGULAR USER

    self.client.logout()
    self.client.login(username=user2.username, password=self.password)

    response = self.client.get(url)

    # HTTP_200_OK
    self.assertEqual(response.status_code, status.HTTP_200_OK)

    # Only 1 user can be returned
    self.assertEqual(response.data['extras']['total_results'], 1)

    # User returned is current user
    self.assertEqual(response.data['users'][0]['username'], user2.username)



    # STAFF USER

    self.client.logout()
    self.client.login(username=staff_user.username, password=self.password)

    response = self.client.get(url)

    # HTTP_200_OK
    self.assertEqual(response.status_code, status.HTTP_200_OK)

    # Superuser cannot be contained in list
    self.assertEqual(response.data['extras']['total_results'], 3)



    # SUPERUSER

    self.client.logout()
    self.client.login(username=superuser.username, password=self.password)

    response = self.client.get(url)

    # HTTP_200_OK
    self.assertEqual(response.status_code, status.HTTP_200_OK)

    # All users contained in list
    self.assertEqual(response.data['extras']['total_results'], 4)

我正在使用以下软件包版本的 python 2.7 工作:

Django==1.8.6
djangorestframework==3.3.1
Markdown==2.6.4
MySQL-python==1.2.5
wheel==0.24.0

更新

我正在使用默认的 django 缓存，这意味着我没有在 django 设置中添加任何关于缓存的内容。

按照建议，我尝试禁用默认的 Django 缓存:

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.dummy.DummyCache',
    }
}

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.SessionAuthentication',
    )
}

问题依然存在。

虽然我不认为问题出在这里，但这是我的 UserViewSet:

api.py(重要部分)

class UserViewSet(  
    mixins.RetrieveModelMixin, 
    mixins.UpdateModelMixin,
    mixins.ListModelMixin,
    viewsets.GenericViewSet
):
    queryset = User.objects.all()
    serializer_class = UserExpenseSerializer
    permission_classes = (IsAuthenticated, )
    allowed_methods = ('GET', 'PATCH', 'OPTIONS', 'HEAD')

    def get_serializer_class(self):
        if self.action == 'retrieve':
            return UserExpenseSerializer
        return UserSerializer

    def get_queryset(self):
        if(self.action == 'list'):
            return User.objects.all()
        if self.request.user.is_superuser:
            return User.objects.all()
        if self.request.user.is_staff:
            return User.objects.exclude(is_superuser=True)
        return User.objects.filter(pk = self.request.user.id)

    def list(self, request):
        filter_obj = UsersFilter(self.request)
        users = filter_obj.do_query()
        extras = filter_obj.get_extras()
        serializer = UserSerializer(users, context={'request' : request}, many=True)
        return Response({'users' : serializer.data, 'extras' : extras}, views.status.HTTP_200_OK)

filters.py

class UsersFilter:
    offset = 0
    limit = 50
    count = 0
    total_pages = 0
    filter_params = {}

    def __init__(self, request):

        if not request.user.is_superuser:
            self.filter_params['is_superuser'] = False

        if (not request.user.is_superuser and not request.user.is_staff):
            self.filter_params['pk'] = request.user.id

        # Read query params
        rpp = request.query_params.get('rpp') or 50
        page = request.query_params.get('page') or 1
        search_string = request.query_params.get('search')

        # Validate

        self.rpp = int(rpp) or 50
        self.page = int(page) or 1

        # Set filter
        set_if_not_none(self.filter_params, 'username__contains', search_string)

        # Count total results

        self.count = User.objects.filter(**self.filter_params).count()
        self.total_pages = int(self.count / self.rpp) + 1

        # Set limits
        self.offset = (self.page - 1) * self.rpp
        self.limit = self.page * self.rpp

    def get_filter_params(self):
        return self.filter_params

    def get_offset(self):
        return self.offset

    def get_limit(self):
        return self.limit

    def do_query(self):
        users = User.objects.filter(**self.filter_params)[self.offset:self.limit]
        return users

    def get_query_info(self):
        query_info = {
            'total_results' : self.count,
            'results_per_page' : self.rpp,
            'current_page' : self.page,
            'total_pages' : self.total_pages
        }
        return query_info

更新 2

正如 Linovia 指出的那样，问题不是缓存或任何其他 DRF 问题，而是过滤器。这是固定的过滤器类:

class UsersFilter:

    def __init__(self, request):

        self.filter_params = {}
        self.offset = 0
        self.limit = 50
        self.count = 0
        self.total_pages = 0
        self.extras = {}

        if not request.user.is_superuser:
        # and so long...

最佳答案

实际上，您创建了一个新用户，它应该有 2 个用户，并且您根据 3 断言了长度。即使没有缓存也无法工作。

编辑: 所以你实际上遇到了问题，因为在类级别使用了可变对象。

这是邪恶的代码:

class UsersFilter:
    filter_params = {}

    def __init__(self, request):
        if not request.user.is_superuser:
            self.filter_params['is_superuser'] = False

实际上应该是:

class UsersFilter:
    def __init__(self, request):
        filter_params = {}
        if not request.user.is_superuser:
            self.filter_params['is_superuser'] = False

否则 UsersFilter.filter_params 将从一个请求到另一个请求保持不变，并且永远不会重置。参见 http://www.toptal.com/python/python-class-attributes-an-overly-thorough-guide有关此的更多详细信息。

关于python - Django REST Framework 缓存错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33830283/

python - Django REST Framework 缓存错误