drg-视图简写流程分析

Posted 2020-12-16 liqianxin

视图简写

目录

• 视图简写
  • 1 请求和响应
    • 1.1 请求
    • 1.2 响应
  • 2 视图
    • 2.1 利用APIView写接口
    • 2.2 基于GenericAPIView写的接口
    • 2.3 基于GenericAPIView和5个视图扩展类写的接口
    • 2.4 使用ModelViewSet编写5个接口
    • 2.5 源码分析ViewSetMixin
    • 2.6 继承ViewSetMixin的视图类

1 请求和响应

1.1 请求

from rest_framework.request import Resquest

# 在Resuquest中，对原生request进行了一次封装,self._request = request
def __getattr__(self, item):
    return getattr(self._request, item)

# 请求对象.data中存放的就是三种编码方式传入的数据，都可以取出来
# 请求对象.query_params 效果等同于django标准的request.GET相同。 

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):
‘‘‘
Response类中的init进行解析：
    data:要返回的数据，字典
    status:返回的状态码 默认是200
        from rest_framework import status中存放的是所有用到的状态码是常量。
    template_name: 渲染的模板名字，有默认的模板，也可以自己定制
    headers:响应头，可以向响应头中放东西。字典
    content_type：响应的编码格式：application/json或text/html
    
    通过浏览器响应会有一个模板文件返回，而postman发出请求返回的是json格式数据，这是通过配置实现的。 
‘‘‘

# 如果把第二个浏览器渲染器注释掉，那么都会返回Json格式数据。


# 也可以设置生效范围
    # 局部使用：只针对某个视图类使用
        from rest_framework.renderers import JSONRenderer
        renderer_classes=[JSONRenderer,]

    # 也可以设置全局使用
        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：

1. APIView:继承View类。views.py函数中定义的CBV可以是继承APIView
2. GenericAPIView:继承APIView类。

2.1 利用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 BooksView(APIView):
    def get(self, request):
        response_dict = Response_dict()
        book_list = models.Book.objects.all()
        book_ser = BookModelSerializer(instance=book_list, many=True)
        response_dict.data = book_ser.data
        return Response(response_dict.dic)

    def post(self, request):
        book_ser = BookModelSerializer(data=request.data)
        response_dict = Response_dict()
        if book_ser.is_valid():
            book_ser.save()
            response_dict.data = book_ser.data
        else:
            response_dict.status = 201
            response_dict.msg = ‘凉凉‘
            response_dict.data = book_ser.errors
        return Response(response_dict.dic)


class BookView(APIView):
    def get(self,request, pk):
        book_obj = models.Book.objects.filter(pk=pk).first()
        book_ser = BookModelSerializer(instance=book_obj)
        response_dict = Response_dict()
        response_dict.data = book_ser.data
        return Response_dict(response_dict.dic)



    def put(self, request, pk):
        response_dict = Response_dict()
        book_obj = models.Book.objects.filter(pk=pk).first()
        book_ser = BookModelSerializer(instance=book_obj, data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            response_dict.data = book_obj
        else:
            response_dict.status = 202
            response_dict.msg = ‘数据校验出问题啦‘
            response_dict.data = book_ser.errors
        return Response(response_dict.dic)

    def delete(self, request, pk):
        models.Book.objects.filter(pk=pk).delete()
        response_dict = Response_dict()
        return Response(response_dict.dic)

    
# urls.py
    url(r‘^books/(d+)‘, views.BookView.as_view())
    url(r‘^books/‘, views.BooksView.as_view())

2.2 基于GenericAPIView写的接口

from rest_framework.generics import GenericAPIView
# views.py
class BooksView(GenericAPIView):

    queryset = models.Book.objects
    serializer_class = BookModelSerializer

    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_vaild():
            book_ser.save()
            return Response(book_ser.data)
        else:
            return Response(book_ser.data)


class BookView(GenericAPIView):
    queryset = models.Book.objects
    serializer_class = BookModelSerializer

    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(insatnce=book, data=request.data)
        if book_ser.is_vaild():
            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‘})
    
# urls.py
    url(r‘^books/(?P<pk>d+)‘, views.BookView.as_view()),
    url(r‘^books/‘, views.BooksView.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, DestroyModelMixin, RetrieveModelMixin,UpdateModelMixin

class BookView(ListModelMixin, CreateModelMixin, GenericAPIView):
    queryset=models.Book.objects
    serializer_class = BookModelSerializer

    def get(self, request):
        return self.list(request)

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


class BooksView(UpdateModelMixin, DestroyModelMixin, RetrieveModelMixin, GenericAPIView):
    queryset = models.Book.objects
    serializer_class = BookModelSerializer

    def get(self,request, pk):
        return self.retrieve(request, pk)

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

    def delete(self,request, pk):
        return self.destroy(request, pk)

2.4 使用ModelViewSet编写5个接口

# views.py
from rest_framework.viewsets import ModelViewSet

# 四行代码搞定5个接口
class BookView(ModelViewSet):
    queryset = model.Book.objects
    serializer_class = BookSerializer
    
# urls.py
# 使用ModelViewSet编写5个接口
    url(r‘^books/(?P<pk>d+)‘, views.BookView.as_view(actions={‘get‘:‘retrieve‘, ‘put‘:‘update‘,‘delete‘:‘destroy‘})),
    url(r‘^books/‘, views.BooksView.as_view(actions={‘get‘:‘list‘, ‘post‘:‘create‘})),
    
    # 路径匹配时，如果是get请求，会执行list方法

2.5 源码分析ViewSetMixin

# 重写了as_view
for method, action in actions.items():
    handler = getattr(self, action)  # 使用反射，handler就是对应函数方法的内存地址
    setattr(self, method, handler)  # 反射，设置属性对应handler
    

2.6 继承ViewSetMixin的视图类

from rest_framework.viewsets import ViewSetMixin
class BookBiew(ViewSetMixin, APIView):
    def get_all_book(self, request):
        print(‘xxx‘)
        book_list = models.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
    url(r‘^books/‘,views.BookView.as_view(actions={‘get‘:‘get_all_book‘}))