自动化测试平台开发（十）：接口测试 - 问题记录 - DRF实现分组查询

前面几篇做了前后端核心功能实现的示例，然后就记录最终demo结果。但是实现起来，期间踩过好些坑。本篇开始总结一下这期间遇到的问题即解决方案。

Django restframework ViewSet 封装实现分组查询

from django.db.models import Count
from rest_framework.viewsets import GenericViewSet
from rest_framework import filters
from django_filters.rest_framework import DjangoFilterBackend


class GroupCountModelMixin(GenericViewSet):
    """Count a queryset by group."""
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    default_group_by_field = 'id'  # string, field
    default_time_unit = ''  # string, type(group_by_field)=DateTimeField --> year | month | day
    time_unit_str = {
        'year': '%%Y',
        'month': '%%Y-%%m',
        'week': '%%x-%%v',
        'day': '%%Y-%%m-%%d',
    }

    def list(self, request, *args, **kwargs):
        """
        分组查询
        :param request:
            group_by_field: 分组字段
            time_unit: 若按时间分组，可设置时间单位 year | month | day
        :param args:
        :param kwargs:
        :return:
        """
        group_by_field = self.default_group_by_field
        time_unit = self.default_time_unit
        if 'group_by_field' in request.query_params:
            request.query_params._mutable = True
            group_by_field = request.query_params.get('group_by_field')
            request.query_params.__delitem__('group_by_field')
            request.query_params._mutable = False

        if 'time_unit' in request.query_params:
            request.query_params._mutable = True
            time_unit = request.query_params.get('time_unit')
            request.query_params.__delitem__('time_unit')
            request.query_params._mutable = False

        extra_select = {
            group_by_field: "DATE_FORMAT({}, '{}')".format(group_by_field, self.time_unit_str[time_unit])
        } if time_unit else {}
        queryset = self.filter_queryset(self.get_queryset().extra(select=extra_select).values(group_by_field)).\
            order_by(group_by_field).annotate(count=Count("id")).values(group_by_field, "count")
        return Response(data=list(queryset.all()), status=200)