无法将查询集获取到按标签匹配下降的 return 对象列表

Question

我是运行 django 2.1.7，DRF 并使用 taggit。我正在编写自己的自定义查询集来查找对象具有的标签。 url： 示例。com/api/tags=书籍、耳机、睡眠

应该returnJSON有对象的顺序是从包含最多标签到包含至少一个标签。这是 gitgist

from django.db.models import Case, ExpressionWrapper, IntegerField, Q, Value, When

class SpecialSearch(ListAPIView):
    model = Object
    serializer_class = ObjectSerializer

    def get_queryset(self, rs, value):
        """
        Recipe search matching, best matching and kind of matching,
        by filtering against `tags` query parameter in the URL.
        """
        if value:
            tags = [tag.strip() for tag in value.split(',')]
            qs = Object.objects.filter(
                reduce(
                    lambda x, y: x | y, [Q(tags__icontains=tag) for tag in tags]))
            check_matches = map(
                lambda x: Case(
                    When(Q(tags__icontains=x), then=Value(1)),
                        default=Value(0)),
            tags)
            count_matches = reduce(lambda x, y: x + y, check_matches)
            qs = qs.annotate(
            matches=ExpressionWrapper(
                count_matches,
                output_field=IntegerField()))
            qs = qs.order_by('-matches')
        return qs

目前，我提交的这段代码有点效果，但是在提交一系列新标签时 returning 按对象 ID 和 API 端点排序的 json 获胜' 从 API 接收新的 json 转储。我现在完全迷路了。任何帮助将不胜感激。

Answer 1

对于 OP 来说可能为时已晚，但万一有人来看这个，在 count_matches 周围添加 Sum() 可能会成功：

from django.db.models import (Case, ExpressionWrapper, IntegerField, Q, Value, When, Sum)

class SpecialSearch(ListAPIView):
    model = Object
    serializer_class = ObjectSerializer

    def get_queryset(self, rs, value):
        """
        Recipe search matching, best matching and kind of matching,
        by filtering against `tags` query parameter in the URL.
        """
        if value:
            tags = [tag.strip() for tag in value.split(',')]
            qs = Object.objects.filter(
                reduce(
                    lambda x, y: x | y, [Q(tags__icontains=tag) for tag in tags]))
            check_matches = map(
                lambda x: Case(
                    When(Q(tags__icontains=x), then=Value(1)),
                        default=Value(0)),
            tags)
            count_matches = reduce(lambda x, y: x + y, check_matches)
            qs = qs.annotate(
            matches=ExpressionWrapper(
                Sum(count_matches),
                output_field=IntegerField()))
            qs = qs.order_by('-matches')
        return qs

无法将查询集获取到按标签匹配下降的 return 对象列表

Cant get queryset to return list of objects that is descending by tag matches

django

rest

django-rest-framework

drf-queryset