drf 第三弹

一: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
        )
    }

二:视图

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'})),