django-filter 乱用空字段
django-filter messing around with empty field
我设置 django-filter 来过滤我的一些列表。这是其中之一，带有自定义表单：
class BookingListFiltersForm(forms.Form):
state__in = forms.MultipleChoiceField(
choices=Booking.STATE_CHOICES, required=False,
label=_("État"), widget=forms.CheckboxSelectMultiple)
source__in = forms.ModelMultipleChoiceField(
queryset=Platform.objects.all(), required=False,
label=_("Source"), widget=ModelSelect2Multiple(
url='autocomplete:platform'))
class BookingManagerFilter(filters.FilterSet):
payments__date = filters.DateFilter(method='payments__date_filter')
payments__method = filters.ChoiceFilter(
method='payments__method_filter',
choices=BookingPayment.METHOD_CHOICES,
)
class Meta:
model = Booking
fields = {
'period': [
'endswith', 'endswith__gte', 'endswith__lte',
'startswith', 'startswith__gte', 'startswith__lte',
],
'state': ['in'],
'source': ['in'],
'booking_date': ['date', 'date__lte', 'date__gte'],
'accommodation': ['in'],
'guest': ['exact']
}
def get_form_class(self):
return BookingListFiltersForm
def payments__date_filter(self, queryset, name, value):
return queryset.filter(**{name: value})
def payments__method_filter(self, queryset, name, value):
return queryset.filter(**{name: value})
表单是通过GET方式提交的。当字段 "source__in" 为空时，查询字符串类似于“?state__in=1”。在这种情况下，我的页面中没有结果（这出乎意料，如果未填写某个字段，我希望结果不会根据该字段进行过滤）。
我查看了调试工具栏以获取有关已执行 SQL 查询的更多信息。令人惊讶的是，我没有找到相关查询集的 SQL 查询！ （如果 querystring 是 "?state__in=1&source__in=2" 例如，结果符合预期，我可以在调试工具栏中找到相关查询）
所以我尝试使用 print(str(filters.qs.query)) 来强制对 SQL 查询的印象。新惊喜，这触发了 EmptyResultSet 异常：
Traceback:
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner
35. response = get_response(request)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
128. response = self.process_exception_by_middleware(e, request)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
126. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/base.py" in view
69. return self.dispatch(request, *args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/utils/decorators.py" in _wrapper
62. return bound_func(*args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
21. return view_func(request, *args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/utils/decorators.py" in bound_func
58. return func.__get__(self, type(self))(*args2, **kwargs2)
File "/home/tony/Workspace/cocoonr/utils/views/manager.py" in dispatch
29. return super().dispatch(*args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/base.py" in dispatch
89. return handler(request, *args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/list.py" in get
142. self.object_list = self.get_queryset()
File "/home/tony/Workspace/cocoonr/booking/views/manager.py" in get_queryset
73. queryset = super().get_queryset()
File "/home/tony/Workspace/cocoonr/utils/views/common.py" in get_queryset
118. print(self.filters.qs.query)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/query.py" in __str__
252. sql, params = self.sql_with_params()
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/query.py" in sql_with_params
260. return self.get_compiler(DEFAULT_DB_ALIAS).as_sql()
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/compiler.py" in as_sql
461. where, w_params = self.compile(self.where) if self.where is not None else ("", [])
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/compiler.py" in compile
393. sql, params = node.as_sql(self, self.connection)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/where.py" in as_sql
98. raise EmptyResultSet
Exception Type: EmptyResultSet at /manager/booking/bookings/
Exception Value:
现在我卡住了，我不知道出了什么问题，也不知道如何进一步调试。
为了测试，我尝试传递以下查询字符串：“?state__in=1&source__in=”。在这种情况下，过滤工作正常，但过滤表单显示字段 "source__in".
的错误“« » 不是有效值”
此外，这里是utils/views/common.py中的相关mixin：
class ListFilterMixin:
filters_class = None
default_filters = None
@cached_property
def filters(self):
return self.get_filters()
def get_filters(self):
if self.filters_class:
qstring = self.request.GET
if not qstring and self.default_filters:
qstring = QueryDict(self.default_filters)
return self.filters_class(
qstring, self.get_unfiltered_queryset(), request=self.request)
else:
return None
def get_queryset(self):
print(self.filters.qs.query) # <--- Line 118
# ...
def get_unfiltered_queryset(self):
return super().get_queryset()
以及 booking/views/manager.py 中的视图 class：
class BookingListView(ListView):
"""List of all bookings."""
model = Booking
default_filters = 'state__in=1'
filters_class = BookingManagerFilter
paginate_by = 30
ordering = '-pk'
def get_queryset(self):
queryset = super().get_queryset() # <--- Line 73
# ...
此外，所以你有完整的继承树，注意上面使用的 ListView 是 utils.views.manager.ListView:
class ListView(BulkActionsMixin, ManagerMixin, BaseListView):
pass
而BaseListView是utils.views.common.ListView:
class ListView(ListFilterMixin, AgencyMixin, ContextMixin, BaseListView):
pass
最后一个BaseListView是django.views.generic.list.ListView。
按照 Kamil 的建议使用 ipdb 进行调试，我注意到一件奇怪的事情可能是导致此行为的原因：
ipdb> next
> /home.tony/.venvs/cocoonr/lib/python3.6/site-packages/django_filters/filters.py(167)filter()
166 def filter(self, qs, value):
--> 167 if value != self.null_value:
168 return super().filter(qs, value)
ipdb> self.null_value
'null'
ipdb> value
<QuerySet []>
ipdb> self.field_name
'source'
ipdb> self.lookup_expr
'in'
ipdb>
因此后续代码认为 source__in 不为空并将 source__in=empty_queryset 添加到过滤器中。我猜 django 然后猜测结果不能评估为非空查询集并保存无用的查询。
这是 django-filters 中的错误还是我做错了什么？
我认为文档可以回答您的问题：
It’s not currently possible to filter by an empty string, since empty
values are interpreted as a skipped filter.
GET http://localhost/api/my-model?myfield=
在文档中还有一些可能的解决方案示例。我把其中一个放在这里
Solution 1: Magic values
You can override the filter() method of a filter class to specifically
check for magic values. This is similar to the ChoiceFilter’s null
value handling.
GET http://localhost/api/my-model?myfield=EMPTY
class MyCharFilter(filters.CharFilter):
empty_value = 'EMPTY'
def filter(self, qs, value):
if value != self.empty_value:
return super(MyCharFilter, self).filter(qs, value)
qs = self.get_method(qs)(**{'%s__%s' % (self.name, self.lookup_expr): ""})
return qs.distinct() if self.distinct else qs
现在我觉得没有足够的信息来解决你的问题。我在你的问题下发表了评论。如果您能提供额外的信息，那将极大地帮助理解正在发生的事情。
这里有一些可以帮助您跟踪此错误的提示：
- 安装ipdb。它将帮助您逐步执行代码并检查每个变量。
在第
行之前放置断点 import ipdb;ipdb.set_trace()
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/list.py" in get
142. self.object_list = self.get_queryset()
中找到罪魁祸首
你可以这样做
class BookingManagerFilter(filters.FilterSet):
# your previous code here
def filter_queryset(self, queryset):
import ipdb;ipdb.set_trace()
return super(BookingManagerFilter, self)filter_queryset(queryset):
并且 运行 您的端点 ipdb 将停止该应用程序，您将能够进入代码并检查它。
我终于弄明白了。
显然 django-filters 没有正确处理外键查找 in。例如，source__in 的默认过滤器是 ModelChoiceFilter。所以我不得不明确地将其定义为 ModelMultipleChoiceFilter.
但是我遇到了另一个问题，那就是 source__in=10&source__in=7 粗略地翻译成 Q(source__in=10) | Q(source__in=7)。这会引发异常，因为 10 和 7 不是可迭代的。所以我更改了我的代码以使用 exact 查找而不是 in，但仍然使用 ModelMultipleChoiceFilter。最后，给出以下内容：
class BookingListFiltersForm(forms.Form):
state__in = forms.MultipleChoiceField(
choices=Booking.STATE_CHOICES, required=False,
label=_("État"), widget=forms.CheckboxSelectMultiple)
source = forms.ModelMultipleChoiceField(
queryset=Platform.objects.all(), required=False,
label=_("Source"), widget=ModelSelect2Multiple(
url='autocomplete:platform'))
class BookingManagerFilter(filters.FilterSet):
source = filters.ModelMultipleChoiceFilter(
queryset=Platform.objects.all())
payments__date = filters.DateFilter(method='payments__date_filter')
payments__method = filters.ChoiceFilter(
method='payments__method_filter',
choices=BookingPayment.METHOD_CHOICES,
)
class Meta:
model = Booking
fields = {
'period': [
'endswith', 'endswith__gte', 'endswith__lte',
'startswith', 'startswith__gte', 'startswith__lte',
],
'state': ['in'],
'source': ['exact'],
'booking_date': ['date', 'date__lte', 'date__gte'],
'accommodation': ['exact'],
'guest': ['exact']
}
def get_form_class(self):
return BookingListFiltersForm
我设置 django-filter 来过滤我的一些列表。这是其中之一，带有自定义表单：
class BookingListFiltersForm(forms.Form):
state__in = forms.MultipleChoiceField(
choices=Booking.STATE_CHOICES, required=False,
label=_("État"), widget=forms.CheckboxSelectMultiple)
source__in = forms.ModelMultipleChoiceField(
queryset=Platform.objects.all(), required=False,
label=_("Source"), widget=ModelSelect2Multiple(
url='autocomplete:platform'))
class BookingManagerFilter(filters.FilterSet):
payments__date = filters.DateFilter(method='payments__date_filter')
payments__method = filters.ChoiceFilter(
method='payments__method_filter',
choices=BookingPayment.METHOD_CHOICES,
)
class Meta:
model = Booking
fields = {
'period': [
'endswith', 'endswith__gte', 'endswith__lte',
'startswith', 'startswith__gte', 'startswith__lte',
],
'state': ['in'],
'source': ['in'],
'booking_date': ['date', 'date__lte', 'date__gte'],
'accommodation': ['in'],
'guest': ['exact']
}
def get_form_class(self):
return BookingListFiltersForm
def payments__date_filter(self, queryset, name, value):
return queryset.filter(**{name: value})
def payments__method_filter(self, queryset, name, value):
return queryset.filter(**{name: value})
表单是通过GET方式提交的。当字段 "source__in" 为空时，查询字符串类似于“?state__in=1”。在这种情况下，我的页面中没有结果（这出乎意料，如果未填写某个字段，我希望结果不会根据该字段进行过滤）。
我查看了调试工具栏以获取有关已执行 SQL 查询的更多信息。令人惊讶的是，我没有找到相关查询集的 SQL 查询！ （如果 querystring 是 "?state__in=1&source__in=2" 例如，结果符合预期，我可以在调试工具栏中找到相关查询）
所以我尝试使用 print(str(filters.qs.query)) 来强制对 SQL 查询的印象。新惊喜，这触发了 EmptyResultSet 异常：
Traceback:
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner
35. response = get_response(request)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
128. response = self.process_exception_by_middleware(e, request)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
126. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/base.py" in view
69. return self.dispatch(request, *args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/utils/decorators.py" in _wrapper
62. return bound_func(*args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
21. return view_func(request, *args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/utils/decorators.py" in bound_func
58. return func.__get__(self, type(self))(*args2, **kwargs2)
File "/home/tony/Workspace/cocoonr/utils/views/manager.py" in dispatch
29. return super().dispatch(*args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/base.py" in dispatch
89. return handler(request, *args, **kwargs)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/list.py" in get
142. self.object_list = self.get_queryset()
File "/home/tony/Workspace/cocoonr/booking/views/manager.py" in get_queryset
73. queryset = super().get_queryset()
File "/home/tony/Workspace/cocoonr/utils/views/common.py" in get_queryset
118. print(self.filters.qs.query)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/query.py" in __str__
252. sql, params = self.sql_with_params()
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/query.py" in sql_with_params
260. return self.get_compiler(DEFAULT_DB_ALIAS).as_sql()
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/compiler.py" in as_sql
461. where, w_params = self.compile(self.where) if self.where is not None else ("", [])
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/compiler.py" in compile
393. sql, params = node.as_sql(self, self.connection)
File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/db/models/sql/where.py" in as_sql
98. raise EmptyResultSet
Exception Type: EmptyResultSet at /manager/booking/bookings/
Exception Value:
现在我卡住了，我不知道出了什么问题，也不知道如何进一步调试。
为了测试，我尝试传递以下查询字符串：“?state__in=1&source__in=”。在这种情况下，过滤工作正常，但过滤表单显示字段 "source__in".
的错误“« » 不是有效值”此外，这里是utils/views/common.py中的相关mixin：
class ListFilterMixin:
filters_class = None
default_filters = None
@cached_property
def filters(self):
return self.get_filters()
def get_filters(self):
if self.filters_class:
qstring = self.request.GET
if not qstring and self.default_filters:
qstring = QueryDict(self.default_filters)
return self.filters_class(
qstring, self.get_unfiltered_queryset(), request=self.request)
else:
return None
def get_queryset(self):
print(self.filters.qs.query) # <--- Line 118
# ...
def get_unfiltered_queryset(self):
return super().get_queryset()
以及 booking/views/manager.py 中的视图 class：
class BookingListView(ListView):
"""List of all bookings."""
model = Booking
default_filters = 'state__in=1'
filters_class = BookingManagerFilter
paginate_by = 30
ordering = '-pk'
def get_queryset(self):
queryset = super().get_queryset() # <--- Line 73
# ...
此外，所以你有完整的继承树，注意上面使用的 ListView 是 utils.views.manager.ListView:
class ListView(BulkActionsMixin, ManagerMixin, BaseListView):
pass
而BaseListView是utils.views.common.ListView:
class ListView(ListFilterMixin, AgencyMixin, ContextMixin, BaseListView):
pass
最后一个BaseListView是django.views.generic.list.ListView。
按照 Kamil 的建议使用 ipdb 进行调试，我注意到一件奇怪的事情可能是导致此行为的原因：
ipdb> next
> /home.tony/.venvs/cocoonr/lib/python3.6/site-packages/django_filters/filters.py(167)filter()
166 def filter(self, qs, value):
--> 167 if value != self.null_value:
168 return super().filter(qs, value)
ipdb> self.null_value
'null'
ipdb> value
<QuerySet []>
ipdb> self.field_name
'source'
ipdb> self.lookup_expr
'in'
ipdb>
因此后续代码认为 source__in 不为空并将 source__in=empty_queryset 添加到过滤器中。我猜 django 然后猜测结果不能评估为非空查询集并保存无用的查询。
这是 django-filters 中的错误还是我做错了什么？
我认为文档可以回答您的问题：
It’s not currently possible to filter by an empty string, since empty values are interpreted as a skipped filter.
GET http://localhost/api/my-model?myfield=
在文档中还有一些可能的解决方案示例。我把其中一个放在这里
Solution 1: Magic values
You can override the filter() method of a filter class to specifically check for magic values. This is similar to the ChoiceFilter’s null value handling.
GET http://localhost/api/my-model?myfield=EMPTYclass MyCharFilter(filters.CharFilter): empty_value = 'EMPTY' def filter(self, qs, value): if value != self.empty_value: return super(MyCharFilter, self).filter(qs, value) qs = self.get_method(qs)(**{'%s__%s' % (self.name, self.lookup_expr): ""}) return qs.distinct() if self.distinct else qs
现在我觉得没有足够的信息来解决你的问题。我在你的问题下发表了评论。如果您能提供额外的信息，那将极大地帮助理解正在发生的事情。
这里有一些可以帮助您跟踪此错误的提示：
- 安装ipdb。它将帮助您逐步执行代码并检查每个变量。
在第
行之前放置断点import ipdb;ipdb.set_trace()File "/home/tony/.venvs/cocoonr/lib/python3.6/site-packages/django/views/generic/list.py" in get 142. self.object_list = self.get_queryset()
你可以这样做
class BookingManagerFilter(filters.FilterSet):
# your previous code here
def filter_queryset(self, queryset):
import ipdb;ipdb.set_trace()
return super(BookingManagerFilter, self)filter_queryset(queryset):
并且 运行 您的端点 ipdb 将停止该应用程序，您将能够进入代码并检查它。
我终于弄明白了。
显然 django-filters 没有正确处理外键查找 in。例如，source__in 的默认过滤器是 ModelChoiceFilter。所以我不得不明确地将其定义为 ModelMultipleChoiceFilter.
但是我遇到了另一个问题，那就是 source__in=10&source__in=7 粗略地翻译成 Q(source__in=10) | Q(source__in=7)。这会引发异常，因为 10 和 7 不是可迭代的。所以我更改了我的代码以使用 exact 查找而不是 in，但仍然使用 ModelMultipleChoiceFilter。最后，给出以下内容：
class BookingListFiltersForm(forms.Form):
state__in = forms.MultipleChoiceField(
choices=Booking.STATE_CHOICES, required=False,
label=_("État"), widget=forms.CheckboxSelectMultiple)
source = forms.ModelMultipleChoiceField(
queryset=Platform.objects.all(), required=False,
label=_("Source"), widget=ModelSelect2Multiple(
url='autocomplete:platform'))
class BookingManagerFilter(filters.FilterSet):
source = filters.ModelMultipleChoiceFilter(
queryset=Platform.objects.all())
payments__date = filters.DateFilter(method='payments__date_filter')
payments__method = filters.ChoiceFilter(
method='payments__method_filter',
choices=BookingPayment.METHOD_CHOICES,
)
class Meta:
model = Booking
fields = {
'period': [
'endswith', 'endswith__gte', 'endswith__lte',
'startswith', 'startswith__gte', 'startswith__lte',
],
'state': ['in'],
'source': ['exact'],
'booking_date': ['date', 'date__lte', 'date__gte'],
'accommodation': ['exact'],
'guest': ['exact']
}
def get_form_class(self):
return BookingListFiltersForm