Django REST框架:使用def update()在ViewSet中不允许使用方法PUT

Question

在DRF中,我有一个像这样的简单ViewSet:

class MyViewSet(viewsets.ViewSet):       

    def update(self, request):
        # do things...
        return Response(status=status.HTTP_200_OK)

当我尝试PUT请求时,我得到一个错误,如方法PUT不允许.如果我使用def put(self, request):所有的东西工作正常.因此到的文档,我应该使用def update():没有def put():,为什么会发生？

Answer 1

有时它对于POST和PUT是不同的,因为PUT在URL中使用id 在这种情况下,yoy会得到这个错误:" PUT不允许 ".

例:

• POST: /api/users/
• 放: /api/users/1/

希望它能为某人节省大量时间

Answer 2

此代码有类似的"方法PUT不允许"问题,因为请求中缺少"id":

class ProfileStep2Serializer(serializers.ModelSerializer):
    class Meta:
        model = Profile
        fields = ('middle_initial', 'mobile_phone', 'address', 'apt_unit_num', 'city', 'state', 'zip')

class Step2ViewSet(viewsets.ModelViewSet):
    serializer_class = ProfileStep2Serializer

    def get_queryset(self):
        return Profile.objects.filter(pk=self.request.user.profile.id)

原来我在序列化器字段中错过了'id',因此PUT请求无法为记录提供id.序列化器的固定版本如下:

class ProfileStep2Serializer(serializers.ModelSerializer):
    class Meta:
        model = Profile
        fields = ('id', 'middle_initial', 'mobile_phone', 'address', 'apt_unit_num', 'city', 'state', 'zip')

Answer 3

这个答案是正确的，Django REST Framework: method PUT not allowed in ViewSet with def update()，PUT 是不允许的，因为 DRF 期望实例 id 位于 URL 中。话虽如此，在 ViewSet 中使用此 mixin 可能是修复它的最佳方法（来自下面粘贴的https://gist.github.com/tomchristie/a2ace4577eff2c603b1b复制粘贴）

class AllowPUTAsCreateMixin(object):
    """
    The following mixin class may be used in order to support PUT-as-create
    behavior for incoming requests.
    """
    def update(self, request, *args, **kwargs):
        partial = kwargs.pop('partial', False)
        instance = self.get_object_or_none()
        serializer = self.get_serializer(instance, data=request.data, partial=partial)
        serializer.is_valid(raise_exception=True)

        if instance is None:
            lookup_url_kwarg = self.lookup_url_kwarg or self.lookup_field
            lookup_value = self.kwargs[lookup_url_kwarg]
            extra_kwargs = {self.lookup_field: lookup_value}
            serializer.save(**extra_kwargs)
            return Response(serializer.data, status=status.HTTP_201_CREATED)

        serializer.save()
        return Response(serializer.data)

    def partial_update(self, request, *args, **kwargs):
        kwargs['partial'] = True
        return self.update(request, *args, **kwargs)

    def get_object_or_none(self):
        try:
            return self.get_object()
        except Http404:
            if self.request.method == 'PUT':
                # For PUT-as-create operation, we need to ensure that we have
                # relevant permissions, as if this was a POST request.  This
                # will either raise a PermissionDenied exception, or simply
                # return None.
                self.check_permissions(clone_request(self.request, 'POST'))
            else:
                # PATCH requests where the object does not exist should still
                # return a 404 response.
                raise

Answer 4

这是因为APIView没有为.put()方法定义处理程序，因此传入的请求无法映射到视图上的处理程序方法，从而引发异常。

（注：viewsets.ViewSet继承自ViewSetMixin和APIView）

中的dispatch()方法APIView检查是否为请求定义了方法处理程序method。如果该dispatch()方法找到请求方法的处理程序，则返回适当的响应。否则，它会引发异常MethodNotAllowed。

根据类中dispatch()方法的源代码APIView：

def dispatch(self, request, *args, **kwargs):       
        ...
        ...    
        try:
            self.initial(request, *args, **kwargs)

            # Get the appropriate handler method
            if request.method.lower() in self.http_method_names:
                 # here handler is fetched for the request method
                 # `http_method_not_allowed` handler is assigned if no handler was found
                handler = getattr(self, request.method.lower(),
                                  self.http_method_not_allowed)
            else:
                handler = self.http_method_not_allowed 

            response = handler(request, *args, **kwargs) # handler is called here

        except Exception as exc:
            response = self.handle_exception(exc)

        self.response = self.finalize_response(request, response, *args, **kwargs)
        return self.response

由于.put()方法处理程序未在您的视图中定义，DRF 调用回退处理程序.http_method_not_allowed。这引发了一个MethodNotAllowed例外。

的源代码.http_method_not_allowed()是：

def http_method_not_allowed(self, request, *args, **kwargs):
    """
    If `request.method` does not correspond to a handler method,
    determine what kind of exception to raise.
    """
    raise exceptions.MethodNotAllowed(request.method) # raise an exception 

当您.put()在视图中定义时，为什么它有效？

当您def put(self, request):在视图中定义时，DRF 可以将传入的请求方法映射到视图上的处理程序方法。这导致返回适当的响应，而不会引发异常。