DRF开发避坑指南01

在当今快速发展的Web开发领域，Django REST Framework（DRF）以其强大的功能和灵活性成为了众多开发者的首选。然而，错误的使用方法不仅会导致项目进度延误，还可能影响性能和安全性。本文将从我个人本身遇到的相关坑来给大家避坑。

一、API性能优化

坑：响应太慢！！！！！！

import os
from django_filters.rest_framework import DjangoFilterBackendfrom rest_framework import viewsets
from rest_framework import filters
from rest_framework import permissions, authentication
from rest_framework.decorators import action
from rest_framework_simplejwt.authentication import JWTAuthenticationfrom utils.rest_framework_util.pagination import CommonPagination
from utils.rest_framework_util.response import rtn_success_info, rtn_error_info
from utils.rest_framework_util.excel_util import ExcelUtil, write_excel_file
from utils.utils import get_current_time_format
from utils.oss.tx_upload import CommonUpload
from drf_yasg import openapi__all__ = {"CommonViewSet","CommonUserViewSet"
}from drf_yasg.utils import swagger_auto_schema
from drf_yasg import openapiclass CommonViewSet(viewsets.ModelViewSet):permission_classes = ()authentication_classes = ()filter_backends = [ DjangoFilterBackend, filters.SearchFilter]search_fields = ["id"]save_export_folder = "static/save_export/"pagination_class = CommonPaginationdef list(self, request, *args, **kwargs):queryset = self.filter_queryset(self.get_queryset())len_model = len(queryset)page = self.paginate_queryset(queryset)if page is not None:serializer = self.get_serializer(page, many=True)response_data = {"total": len_model,"list": serializer.data}return rtn_success_info(response_data, msg="查询数据成功")serializer = self.get_serializer(queryset, many=True)return rtn_success_info(serializer.data)def retrieve(self, request, *args, **kwargs):instance = self.get_object()serializer = self.get_serializer(instance)return rtn_success_info(serializer.data)def update(self, request, *args, **kwargs):"""put 修改"""try:partial = kwargs.pop('partial', False)instance = self.get_object()serializer = self.get_serializer(instance, data=request.data, partial=partial)serializer.is_valid(raise_exception=True)self.perform_update(serializer)if getattr(instance, '_prefetched_objects_cache', None):# If 'prefetch_related' has been applied to a queryset, we need to# forcibly invalidate the prefetch cache on the instance.instance._prefetched_objects_cache = {}return rtn_success_info(serializer.data, msg='修改数据成功')except Exception as e:return rtn_error_info(msg=e)def destroy(self, request, *args, **kwargs):instance = self.get_object()self.perform_destroy(instance)return rtn_success_info(msg="数据删除成功")def perform_destroy(self, instance):instance.delete()def create(self, request, *args, **kwargs):serializer = self.get_serializer(data=request.data)serializer.is_valid(raise_exception=True)self.perform_create(serializer)return rtn_success_info(serializer.data, msg="创建数据成功")@action(detail=False, methods=['POST'])def data_import(self, request, *args, **kwargs):response_data_list = []file = request.FILES.get("file", None)if file is None:return rtn_error_info("需要传入file文件")else:title_list, data_list = ExcelUtil(file).read_data()serializer_class = self.get_serializer_class()model = serializer_class.Meta.modeltry:if model is not None:model.objects.create()for create_data in data_list:response_data = {}for index_, title in enumerate(title_list):response_data[title] = create_data[index_]if response_data.get('id', None) is not None:response_data.pop("id")serializer = self.get_serializer(data=response_data)if serializer.is_valid():# 创建self.perform_create(serializer)except Exception as e:return rtn_error_info(f"数据导入失败:{e}")response_data_list = data_listreturn rtn_success_info(data=response_data_list, msg='导入数据成功')@action(detail=False, methods=['POST'])def data_export(self, request, *args, **kwargs):id_list = request.data.get('ids', None)queryset = self.get_queryset()row_data_list = []is_first = Falsetitle_list = []title = ""for data in queryset:title = data.__class__.__name__if not is_first:data_list = []for data_meta in data._meta.fields:data_list.append(data_meta.name)title_list.append(data_meta.name)row_data_list.append(data_list)  # titleis_first = Truebreakfor value_data in queryset.values():data_info = []if id_list is not None:for id_ in id_list:if int(value_data['id']) == int(id_):for title in title_list:data_info.append(value_data[title])else:for title in title_list:data_info.append(value_data[title])if len(data_info) > 0:row_data_list.append(data_info)excel_file_name = f"{title}_{get_current_time_format('%Y_%m_%d_%H_%M_%S')}.xlsx"if not os.path.exists(self.save_export_folder):os.makedirs(self.save_export_folder)write_excel_file(row_data_list, f"{self.save_export_folder}{excel_file_name}")if os.path.exists(f"{self.save_export_folder}{excel_file_name}"):url = CommonUpload().cos_upload_file(f"{self.save_export_folder}{excel_file_name}")data = {'excel_url': url}return rtn_success_info(data, '导出成功')return rtn_error_info("导出失败")class CommonUserViewSet(CommonViewSet):"""带用户权限的ViewSetArgs:viewsets (_type_): _description_Returns:_type_: _description_"""permission_classes = [permissions.IsAuthenticated]authentication_classes = [JWTAuthentication, authentication.SessionAuthentication,authentication.BasicAuthentication]def create(self, request, *args, **kwargs):data = request.datadata["user"] = request.user.idserializer = self.get_serializer(data=data)serializer.is_valid(raise_exception=True)self.perform_create(serializer)return rtn_success_info(serializer.data, msg="创建数据成功")def list(self, request, *args, **kwargs):queryset = self.filter_queryset(self.get_queryset())len_model = len(queryset)page = self.paginate_queryset(queryset)if page is not None:serializer = self.get_serializer(page, many=True)response_data = {"total": len_model,"list": serializer.data}return rtn_success_info(response_data, msg="查询数据成功")serializer = self.get_serializer(queryset, many=True)return rtn_success_info(serializer.data)

以这块代码为例，大家会发现一个问题，虽然都封装了ViewSet，但是他的响应速度比之前慢很多，原因何在，问题就出现在len_model = len(queryset)上，因为当前的len(queryset)会遍历每一个model，导致性能缓慢，正确的修改方式是使用queryset.count()，会大幅度的提高性能，直接获取里面的变量。
图片

二、复杂权限管理
针对于这类的权限管理，其实DRF也给咱们弄好了，但是基于实际业务场景的复杂性，本人也提供给大家一个参考的可定制化的代码！
1.通过定制通用类的permissions

class CommonUserViewSet(CommonViewSet):"""带用户权限的ViewSetArgs:viewsets (_type_): _description_Returns:_type_: _description_"""permission_classes = [permissions.IsAuthenticated]authentication_classes = [JWTAuthentication, authentication.SessionAuthentication,authentication.BasicAuthentication]``
类似这个，这个是用于基础的认证，比方说用户需要登陆才能确认的，使用这个比较方便。
![在这里插入图片描述](https://i-blog.csdnimg.cn/direct/07b878dcf2d641b79e9700d6a8ade683.png)2.特定用户
这类的需求，可以通过获取self.request.user来判断，其中可以通过获取用户是否为超级用户，以及username等判断，大大提高drf的灵活性！![在这里插入图片描述](https://i-blog.csdnimg.cn/direct/8ddab551e10942f7a1b7ebc0d0dd9686.png)最后，大家还遇到哪些坑，也可以分享在评论区中，大家一起排雷，祝大家春节喜乐！觉得有用的话可以分享以及关注哈！