django 返回 url kwarg string 用于过滤作为 int，试图用作 pk

Question

观察下面的url

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

此 url 绑定到一个资源，该资源将 return 一个城市中所有街区的列表。

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过这个问题了：

并已实施这些建议，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 agrument 作为主键

这是我的 url、视图、序列化程序和模型代码

url:

  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追溯的完整打印：

  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

您的问题在这里：

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

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

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。

django 返回 url kwarg string 用于过滤作为 int，试图用作 pk

django returning url kwarg string used for filtering as an int, trying to use as pk

python

sql

django

django-rest-framework

traceback