Question

我需要限制已过滤的查询，因为它需要花费很多时间来执行。我知道django在添加过滤器后执行查询，所以这个解决方案非常合适。与此同时，我正在使用django-rest-framework，但我使用的代码片段非常简单。以下是视图的代码段示例：

class ProductList(generics.ListAPIView):
    queryset = Product.objects.all()
    serializer_class = ProductSerializer
    filter_backends = (filters.DjangoFilterBackend,)
    filter_fields = ('category', 'in_stock')

但是当我将其更改为Product.objects.all()[:10]时，我收到错误。

使用django-rest和django-filters时是否可以侥幸逃脱？

以下是完整的追溯：

Traceback:
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django/core/handlers/base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django/views/decorators/csrf.py" in wrapped_view
  58.         return view_func(*args, **kwargs)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django/views/generic/base.py" in view
  71.             return self.dispatch(request, *args, **kwargs)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/rest_framework/views.py" in dispatch
  466.             response = self.handle_exception(exc)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/rest_framework/views.py" in dispatch
  463.             response = handler(request, *args, **kwargs)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/rest_framework/generics.py" in get
  201.         return self.list(request, *args, **kwargs)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/rest_framework/mixins.py" in list
  40.         queryset = self.filter_queryset(self.get_queryset())
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/rest_framework/generics.py" in filter_queryset
  151.             queryset = backend().filter_queryset(self.request, queryset, self)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/rest_framework/filters.py" in filter_queryset
  73.             return filter_class(request.query_params, queryset=queryset).qs
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django_filters/filterset.py" in qs
  375.                     qs = filter_.filter(qs, value)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django_filters/filters.py" in filter
  87.         qs = self.get_method(qs)(**{'%s__%s' % (self.name, lookup): value})
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django/db/models/query.py" in filter
  679.         return self._filter_or_exclude(False, *args, **kwargs)
File "/Users/rod/Documents/htdocs/test3+/venv/lib/python3.5/site-packages/django/db/models/query.py" in _filter_or_exclude
  691.                 "Cannot filter a query once a slice has been taken."

Exception Type: AssertionError at /query/
Exception Value: Cannot filter a query once a slice has been taken.

切片拍摄后无法过滤查询

0 个答案: