python-Django Rest Framework-过滤器嵌套一对多

我想要一个具有各自任务的用户列表,并按任务开始日期过滤.

# Pseudo json
User 1
  - mission 1
  - mission 2
User 2
  - mission 1
  - mission 2
  - mission 3

我的数据结构：

楷模：

class Mission(models.Model):
  start = models.DateTimeField()
  user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="missions")

序列化器：

# Mission
class MissionSerializer(serializers.ModelSerializer):
  class Meta:
    model  = Mission
    fields = (
      'start',
      'end',
    )

# User
class UserSerializer(serializers.ModelSerializer):
  missions = MissionSerializer(many=True)
  class Meta:
    model  = MyUser
    fields = (
      'username',
      'missions',
    )

视图集：

# Filter
class UserFilter(django_filters.FilterSet):
  class Meta:
    model  = MyUser
    fields = {
      'missions__start': ['gte','lt']
    }

# Viewset
class UserViewset(viewsets.ModelViewSet):
  filter_backends  = (filters.OrderingFilter, filters.DjangoFilterBackend,)
  filter_class     = UserFilter
  serializer_class = UserSerializer

  @list_route(methods=['get'])
  def listCalendar(self, request):
    prefetched_missions = Prefetch('missions', queryset=Mission.objects.all())
    objects_list = MyUser.objects.prefetch_related( prefetched_missions )
    objects_list = self.filter_queryset(objects_list)
    serializer   = UserSerializer(objects_list, many=True)
    return Response(serializer.data)

我的问题：

调用此URL时：

/api/users/listCalendar/?start__gte=2015-06-29&start__lt=2015-08-10

该过滤器被忽略,我想不出一种使它起作用的方法.
我的直觉是问题在于ViewSet中的Mission.objects.all()应该类似于：Mission.objects.filter(*但是这里是什么？*)

任何帮助将不胜感激！

编辑1：

有一些进步！但是仍然无法正常工作…正如您建议的Mark Galloway一样,我尝试调用以下网址：

/api/users/listCalendar/?missions__start__gte=2015-06-29&missions__start__lt=2015-08-10

但这是要执行的查询：

SELECT "app_myuser"."id", "app_myuser"."username"
FROM "app_myuser"
INNER JOIN "app_mission" ON ( "app_myuser"."id" = "app_mission"."user_id" )
INNER JOIN "app_mission" T4 ON ( "app_myuser"."id" = T4."user_id" )
WHERE ("app_mission"."start" >= '2015-07-06T00:00:00+00:00'::timestamptz
AND T4."start" < '2015-07-12T00:00:00+00:00'::timestamptz)
ORDER BY "app_myuser"."username" ASC;

如您所见,这里有2个INNER JOIN而不是1.由于某些原因,它会将2个过滤后的字段当作在单独的表中.结果是我的结果被复制了.

首先,您的filter_backends list中缺少the DjangoFilterBackend.这就是告诉Django REST框架查看filter_class并将相关过滤应用于请求的原因,否则,您的filter_class将被忽略(如您所见).

class UserViewset(viewsets.ModelViewSet):
    filter_backends = (filters.OrderingFilter, filters.DjangoFilterBackend, )
    filter_class = UserFilter
    serializer_class = UserSerializer

其次,您期望能够使用开始和结束查询参数,但是告诉django-filter查看Meta.fields中的missions__start字段.您可以通过使用别名手动定义FilterSet上的字段来解决此问题

class UserFilter(django_filters.FilterSet):
    start_gte = django_filter.DateTimeFilter(name='missions__start', lookup_type='gte', distinct=True)
    start_lte = django_filter.DateTimeFilter(name='missions__start', lookup_type='lte', distinct=True)

    end_gte = django_filter.DateTimeFilter(name='missions__end', lookup_type='gte', distinct=True)
    end_lte = django_filter.DateTimeFilter(missions__name='end', lookup_type='lte', distinct=True)

    class Meta:
        model  = MyUser
        fields = ('start_gte', 'start_lte', 'end_gte', 'end_lte', )

或者通过仅引用查询参数将获得完整值(missions__start_gte而不是start_gte).

第三,由于INNER JOIN查询如何跨多个表工作,因此在执行影响单个用户下的多个任务的过滤器时,您将收到重复的值.您可以通过在过滤器中使用the distinct argument(如上所示)或在filter_queryset中的过滤器调用末尾添加.distinct()来解决此问题.