django返回用于过滤的url kwarg字符串作为int，试图用作pk

Question

观察下面的网址

http://127.0.0.1:8000/api/neighborhood-list/chicago/

此 url 与一个资源相关联，该资源将返回一个城市中所有社区的列表。

但是我目前收到此错误：

    invalid literal for int() with base 10: 'chicago'
Exception Location: /home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py in get_prep_value, line 966

第 966 行：return int(value)

现在我已经在这里问了这个问题：invalid literal for int() with base ten in listAPI view django rest framework

并且已经实施了这些建议，但我似乎仍在与 django 框架作斗争。看起来 Django 框架默认尝试使用我的关键字 url agument 作为主键

这是我的 url、视图、序列化程序和模型代码

网址：

  url(r'^neighborhood-list/(?P<city>[a-zA-Z]+)/$', NeighborhoodListView.as_view(),
name='neighborhood-list',
    )

查看：

class NeighborhoodListView(generics.ListAPIView):
queryset = Neighborhood.objects.all()
serializer_class = NeighborhoodSerializer(queryset, many=True)

def get_queryset(self):
    return self.queryset.filter(city=self.kwargs.get('city'))

序列化器：

class NeighborhoodSerializer(serializers.ModelSerializer):
    class Meta:
        model = Neighborhood
        fields = 'neighborhood'

型号：

class  Neighborhood(models.Model):
city = models.ForeignKey(City, null=True)
neighborhood = models.CharField(max_length=150, null=False)

如果您愿意，这里是我认为需要的回溯的完整打印：

  Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/api/neighborhood-list/chicago/

Django Version: 1.11.2
Python Version: 2.7.12
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'rest_framework',
 'venue.apps.VenueConfig']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 '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 "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/core/handlers/exception.py" in inner
  41.             response = get_response(request)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/views/decorators/csrf.py" in wrapped_view
  58.         return view_func(*args, **kwargs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/rest_framework/views.py" in dispatch
  489.             response = self.handle_exception(exc)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/rest_framework/views.py" in handle_exception
  449.             self.raise_uncaught_exception(exc)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/rest_framework/views.py" in dispatch
  486.             response = handler(request, *args, **kwargs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/rest_framework/generics.py" in get
  201.         return self.list(request, *args, **kwargs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/rest_framework/mixins.py" in list
  40.         queryset = self.filter_queryset(self.get_queryset())

File "/home/rickus/211hospitality/suitsandtables/backend/suitsandtables/venue/views.py" in get_queryset
  50.         return self.queryset.filter(city=self.kwargs.get('city'))

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/query.py" in filter
  784.         return self._filter_or_exclude(False, *args, **kwargs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/query.py" in _filter_or_exclude
  802.             clone.query.add_q(Q(*args, **kwargs))

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py" in add_q
  1261.         clause, _ = self._add_q(q_object, self.used_aliases)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py" in _add_q
  1287.                     allow_joins=allow_joins, split_subq=split_subq,

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py" in build_filter
  1217.             condition = lookup_class(lhs, value)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/lookups.py" in __init__
  24.         self.rhs = self.get_prep_lookup()

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/fields/related_lookups.py" in get_prep_lookup
  112.                 self.rhs = target_field.get_prep_value(self.rhs)

File "/home/rickus/211hospitality/suitsandtables/backend/venv/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py" in get_prep_value
  966.         return int(value)

Exception Type: ValueError at /api/neighborhood-list/chicago/
Exception Value: invalid literal for int() with base 10: 'chicago'

Answer 1

你的问题在这里：

self.queryset.filter(city=self.kwargs.get('city'))

city 是City 的外键，与其id 属性（整数）匹配。您正在尝试将其与 'chicago' 匹配，这显然作为整数失败，因此出现异常。

这里有两个选项，要么参考城市名称：

self.queryset.filter(city__name=self.kwargs.get('city'))

或者先获取City对象：

city = City.objects.filter(name__contains=self.kwargs.get('city')).first()
self.queryset.filter(city=city)

我在这里使用filter，如果找不到城市，.get() 会引发异常。