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2021
10-16

DRF之请求与响应的实现

1 请求和响应

1.1 请求

# 请求对象
# from rest_framework.request import Request
    def __init__(self, request, parsers=None, authenticators=None,
                 negotiator=None, parser_context=None):
        # 二次封装request,将原生request作为drf request对象的 _request 属性
        self._request = request
    def __getattr__(self,item):
     return getattr(self._request,item)
# 请求对象.data:前端以三种编码方式传入的数据,都可以取出来
# 请求对象..query_params 与Django标准的request.GET相同,只是更换了更正确的名称而已。

1.2 响应

#from rest_framework.response import Response
 def __init__(self, data=None, status=None,
                 template_name=None, headers=None,
                 exception=False, content_type=None):
        
#data:你要返回的数据,字典
#status:返回的状态码,默认是200,
 -from rest_framework import status在这个路径下,它把所有使用到的状态码都定义成了常量
#template_name 渲染的模板名字(自定制模板),不需要了解
#headers:响应头,可以往响应头放东西,就是一个字典
#content_type:响应的编码格式,application/json和text/html;

# 浏览器响应成浏览器的格式,postman响应成json格式,通过配置实现的(默认配置)
#不管是postman还是浏览器,都返回json格式数据
# drf有默认的配置文件---》先从项目的setting中找,找不到,采用默认的
# drf的配置信息,先从自己类中找--》项目的setting中找---》默认的找
 -局部使用:对某个视图类有效
        -在视图类中写如下
        from rest_framework.renderers import JSONRenderer
        renderer_classes=[JSONRenderer,]
    -全局使用:全局的视图类,所有请求,都有效
     -在setting.py中加入如下
        REST_FRAMEWORK = {
            'DEFAULT_RENDERER_CLASSES': (  # 默认响应渲染类
                'rest_framework.renderers.JSONRenderer',  # json渲染器
                'rest_framework.renderers.BrowsableAPIRenderer',  # 浏览API渲染器
            )
        }

2 视图

# 两个视图基类
APIView
GenericAPIView

2.1 基于APIView写接口

#### views.py
from rest_framework.generics import GenericAPIView
from app01.models import Book
from app01.ser import BookSerializer
# 基于APIView写的
class BookView(APIView):
    def get(self,request):
        book_list=Book.objects.all()
        book_ser=BookSerializer(book_list,many=True)

        return Response(book_ser.data)
    def post(self,request):
        book_ser = BookSerializer(data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.data)
        else:
            return Response({'status':101,'msg':'校验失败'})


class BookDetailView(APIView):
    def get(self, request,pk):
        book = Book.objects.all().filter(pk=pk).first()
        book_ser = BookSerializer(book)
        return Response(book_ser.data)

    def put(self, request,pk):
        book = Book.objects.all().filter(pk=pk).first()
        book_ser = BookSerializer(instance=book,data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.data)
        else:
            return Response({'status': 101, 'msg': '校验失败'})

    def delete(self,request,pk):
        ret=Book.objects.filter(pk=pk).delete()
        return Response({'status': 100, 'msg': '删除成功'})
    
#models.py
class Book(models.Model):
    name=models.CharField(max_length=32)
    price=models.DecimalField(max_digits=5,decimal_places=2)
    publish=models.CharField(max_length=32)
#ser.py
class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model=Book
        fields='__all__'
# urls.py
path('books/', views.BookView.as_view()),
re_path('books/(?P<pk>\d+)', views.BookDetailView.as_view()),

2.2 基于GenericAPIView写的接口

# views.py
class Book2View(GenericAPIView):
    #queryset要传queryset对象,查询了所有的图书
    # serializer_class使用哪个序列化类来序列化这堆数据
    queryset=Book.objects
    # queryset=Book.objects.all()
    serializer_class = BookSerializer
    def get(self,request):
        book_list=self.get_queryset()
        book_ser=self.get_serializer(book_list,many=True)

        return Response(book_ser.data)
    def post(self,request):
        book_ser = self.get_serializer(data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.data)
        else:
            return Response({'status':101,'msg':'校验失败'})


class Book2DetailView(GenericAPIView):
    queryset = Book.objects
    serializer_class = BookSerializer
    def get(self, request,pk):
        book = self.get_object()
        book_ser = self.get_serializer(book)
        return Response(book_ser.data)

    def put(self, request,pk):
        book = self.get_object()
        book_ser = self.get_serializer(instance=book,data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.data)
        else:
            return Response({'status': 101, 'msg': '校验失败'})

    def delete(self,request,pk):
        ret=self.get_object().delete()
        return Response({'status': 100, 'msg': '删除成功'})
    
 #url.py
    # 使用GenericAPIView重写的
    path('books2/', views.Book2View.as_view()),
    re_path('books2/(?P<pk>\d+)', views.Book2DetailView.as_view()),

2.3 基于GenericAPIView和5个视图扩展类写的接口

from rest_framework.mixins import  ListModelMixin,CreateModelMixin,UpdateModelMixin,DestroyModelMixin,RetrieveModelMixin
# views.py
class Book3View(GenericAPIView,ListModelMixin,CreateModelMixin):

    queryset=Book.objects
    serializer_class = BookSerializer
    def get(self,request):
        return self.list(request)

    def post(self,request):
        return self.create(request)

class Book3DetailView(GenericAPIView,RetrieveModelMixin,DestroyModelMixin,UpdateModelMixin):
    queryset = Book.objects
    serializer_class = BookSerializer
    def get(self, request,pk):
        return self.retrieve(request,pk)

    def put(self, request,pk):
        return self.update(request,pk)

    def delete(self,request,pk):
        return self.destroy(request,pk)
# urls.py
    # 使用GenericAPIView+5 个视图扩展类  重写的
    path('books3/', views.Book3View.as_view()),
    re_path('books3/(?P<pk>\d+)', views.Book3DetailView.as_view()),

2.4 使用ModelViewSet编写5个接口

# views.py
from rest_framework.viewsets import ModelViewSet
class Book5View(ModelViewSet):  #5个接口都有,但是路由有点问题
    queryset = Book.objects
    serializer_class = BookSerializer
    
# urls.py
# 使用ModelViewSet编写5个接口
    path('books5/', views.Book5View.as_view(actions={'get':'list','post':'create'})), #当路径匹配,又是get请求,会执行Book5View的list方法
    re_path('books5/(?P<pk>\d+)', views.Book5View.as_view(actions={'get':'retrieve','put':'update','delete':'destroy'})),

2.5 源码分析ViewSetMixin

# 重写了as_view
# 核心代码(所以路由中只要配置了对应关系,比如{'get':'list'}),当get请求来,就会执行list方法
for method, action in actions.items():
    #method:get
    # action:list
    handler = getattr(self, action)
    #执行完上一句,handler就变成了list的内存地址
    setattr(self, method, handler)
    #执行完上一句  对象.get=list
    #for循环执行完毕 对象.get:对着list   对象.post:对着create

2.6 继承ViewSetMixin的视图类

# views.py
from rest_framework.viewsets import ViewSetMixin
class Book6View(ViewSetMixin,APIView): #一定要放在APIVIew前
    def get_all_book(self,request):
        print("xxxx")
        book_list = Book.objects.all()
        book_ser = BookSerializer(book_list, many=True)
        return Response(book_ser.data)
    
# urls.py
    #继承ViewSetMixin的视图类,路由可以改写成这样
    path('books6/', views.Book6View.as_view(actions={'get': 'get_all_book'})),

什么是正向代理,什么是反向代理

正向代理代理的对象是客户端,反向代理代理的对象是服务端

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