Django属性错误：模型对象没有'filter'属性

Question

我正在用Django搭建自己的博客。我有一个视图用来显示文章，这个视图是从DetailView扩展而来的。为了避免在处理网址时出现麻烦，我想根据文章的发布日期来分类这些文章。文章的网址大概是这样的（其中pk对应文章的slug）：

r'articles/(?P<year>\d{4})/(?P<month>\d{2})/(?P<day>\d{2})/(?P<pk>[\w-]+)/$'

在我的视图中，我想这样做：

def get_queryset(self):
    year = self.kwargs.get("year", None)
    month = self.kwargs.get("month", None)
    day = self.kwargs.get("day", None)

    publication_date = year + "-" + month + "-" + day

    return Article.objects.get(created_at__startswith=publication_date, slug=self.kwargs.get("pk", None))

但是这样不行，我搞不懂为什么……实际上，当我这样做的时候，它是可以工作的：

return Article.objects.filter(created_at__startswith=publication_date, slug=self.kwargs.get("pk", None))

但是这样返回的是一个查询集，我只想要一篇文章！([0]也会返回同样的错误)

这是错误信息：

AttributeError at /articles/2015/03/04/nouveau-site/
'Article' object has no attribute 'filter'
Django Version: 1.6.2
Exception Location: C:\Python27\lib\site-packages\django\views\generic\detail.py in get_object, line 37
Python Version: 2.7.6

还有完整的错误追踪信息：

Environment:


Request Method: GET
Request URL: http://localhost:8000/articles/2015/03/04/nouveau-site/

Django Version: 1.6.2
Python Version: 2.7.6
Installed Applications:
('django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'groups',
 'posts',
 'users')
Installed Middleware:
('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:\Python27\lib\site-packages\django\core\handlers\base.py" in get_response
  114.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Python27\lib\site-packages\django\views\generic\base.py" in view
  69.             return self.dispatch(request, *args, **kwargs)
File "C:\Python27\lib\site-packages\django\views\generic\base.py" in dispatch
  87.         return handler(request, *args, **kwargs)
File "C:\Python27\lib\site-packages\django\views\generic\detail.py" in get
  110.         self.object = self.get_object()
File "C:\Python27\lib\site-packages\django\views\generic\detail.py" in get_object
  37.             queryset = queryset.filter(pk=pk)

Exception Type: AttributeError at /articles/2015/03/04/nouveau-site/
Exception Value: 'Article' object has no attribute 'filter'

提前谢谢大家！

Answer 1

你也可以使用 get_object() 这个函数。

def get_object(self):
    ...

    return Article.objects.get(created_at__startswith=publication_date, slug=self.kwargs.get("pk", None))

Answer 2

def get_queryset(self):
    ...

    return Article.objects.filter(created_at__startswith=publication_date, slug=self.kwargs.get("pk", None))

因为 get_queryset 必须返回一个查询集对象，而不是模型对象。