django - 'RelatedManager' 对象没有属性 'pk'

Question

我有一个看起来像这样的模型

class Connections(models.Model):
    following = models.ForeignKey(
        User, related_name='following'
    )
    followers = models.ForeignKey(
        User, related_name='followers'
    )
    def __unicode__(self):
        return u'%s, %s' % (self.following.username, self.followers.username)
    class Meta:
        unique_together = (('following', 'followers'), )

然后在 TastyPie 中，我使用以下代码提取以下用户

class ConnectionsResource(ModelResource):
    user_following = fields.ForeignKey(UserResource, 'following')
    user_follower = fields.ForeignKey(UserResource, 'followers')
    class Meta:
        queryset = Connections.objects.all()
        resource_name = 'connections'

    def prepend_urls(self):
        return[
            url(r"^(?P<resource_name>%s)%s$" % (self._meta.resource_name, trailing_slash()), self.wrap_view('connections'), name="api_connections"),
        ]

    def connections(self,request,**kwargs):
        if request.user and request.user.is_authenticated():
            #Scribble Comments
            if request.GET.get('followers', ''):
                user = request.user
                followers = [connections.following for connections in user.followers.all()]
                followers_count = 1
                if followers_count > 0:
                    paginator = Paginator(followers, 20)
                    try:
                        page = paginator.page(int(request.GET.get('page', 1)))
                    except InvalidPage:
                        return self.create_response(request, { 'success': False, 'reason':'no more pages' })
                    objects = []
                    for result in page.object_list:
                        bundle = self.build_bundle(obj=result, request=request)
                        bundle = self.full_dehydrate(bundle)
                        objects.append(bundle)
                    followers_list = {
                    'followers_count': followers_count,
                    'followers' : objects,
                    'success': True,
                    }
                    self.log_throttled_access(request)
                    return self.create_response(request, followers_list)
                else:
                    return self.create_response(request, { 'success': False, 'reason':'No Followers' })
            else:
                return self.create_response(request, { 'success': False, 'reason':'Wrong Query'})
        else:
            return self.create_response(request, { 'success': False, 'reason':'User not Logged in'})

    def determine_format(self, request):
        return 'application/json'

但我不断收到 'RelatedManager' object has no attribute 'pk'错误。我不知道为什么

追溯:

traceback: "Traceback (most recent call last): 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/resources.py", line 202, in wrapper response = callback(request, *args, **kwargs) 
File "/Users/jonathan/virtualenvs/myproject/bin/django_worksquid/scribbler/api.py", line 547, in connections bundle = self.full_dehydrate(bundle) 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/resources.py", line 837, in full_dehydrate bundle.data[field_name] = field_object.dehydrate(bundle) 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/fields.py", line 729, in dehydrate return self.dehydrate_related(fk_bundle, self.fk_resource) 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/fields.py", line 557, in dehydrate_related return related_resource.get_resource_uri(bundle) 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/resources.py", line 784, in get_resource_uri return self._build_reverse_url(url_name, kwargs=self.resource_uri_kwargs(bundle_or_obj)) 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/resources.py", line 763, in resource_uri_kwargs kwargs.update(self.detail_uri_kwargs(bundle_or_obj)) 
File "/Users/jonathan/virtualenvs/myproject/lib/python2.7/site-packages/tastypie/resources.py", line 2371, in detail_uri_kwargs kwargs[self._meta.detail_uri_name] = getattr(bundle_or_obj.obj, self._meta.detail_uri_name) AttributeError: 'RelatedManager' object has no attribute 'pk' "

编辑

当我改变followers_count = 1至 followers_count = followers.count()它给了我

"count() takes exactly one argument (0 given)"  error

编辑

我终于意识到关注者是一个列表而不是一个对象，所以我将代码更改为

def connections(self,request,**kwargs):
    if request.user and request.user.is_authenticated():
        #Scribble Comments
        if request.GET.get('followers', ''):
            user = request.user
            followers = [connections.following for connections in user.followers.all()]
            users_id = [s.id for s in followers]
            users=User.objects.filter(id__in = users_id)
            users_count = users.count()
            users_list = {
            'users_count': users_count,
            'users' : users,
            'success': True,
            }
            return self.create_response(request, users_list)
        else:
            return self.create_response(request, { 'success': False, 'reason':'Wrong Query'})
    else:
        return self.create_response(request, { 'success': False, 'reason':'User not Logged in'})

现在我确实得到了输出，但我是根据对象得到的，比如

success: true,
users: "[<User: abc>, <User: test>, <User: abc2>, <User: test2>]",
users_count: 4

而不是这个，我希望我的对象显示电子邮件地址和所有用户，而不仅仅是这个对象。

Answer 1

解决方法很简单。事实证明，我应该使用 ToManyField对于用户对象不是 ForeignKey ，这解决了一切!