APIView的as_view简单解读

APIView的as_view          在APIView中as_view本质还是调用了父类的as_view（View的as_view）

@classmethod
    def as_view(cls, **initkwargs):
        """
        Store the original class on the view function.

        This allows us to discover information about the view when we do URL
        reverse lookups.  Used for breadcrumb generation.
        """
　　     # 判断类中queryset属性是否存在, 存在的话将一个异常信息保存在类中 
        if isinstance(getattr(cls, 'queryset', None), models.query.QuerySet):
            def force_evaluation():
                raise RuntimeError(
                    'Do not evaluate the `.queryset` attribute directly, '
                    'as the result will be cached and reused between requests. '
                    'Use `.all()` or call `.get_queryset()` instead.'
                )
            cls.queryset._fetch_all = force_evaluation

　　　   # 继承父类的as_view(django.views.View)
        view = super(APIView, cls).as_view(**initkwargs)
        view.cls = cls
        view.initkwargs = initkwargs

        # Note: session based authentication is explicitly CSRF validated,
        # all other authentication is CSRF exempt.
　　     # 所有的请求都没csrf认证
        return csrf_exempt(view)

APIView的dispatch           as_view中调用dispatch -----》这个dispatch是APIView的dispatch

    # Note: Views are made CSRF exempt from within `as_view` as to prevent
    # accidental removal of this exemption in cases where `dispatch` needs to
    # be overridden.
    def dispatch(self, request, *args, **kwargs):
        """
        `.dispatch()` is pretty much the same as Django's regular dispatch,
        but with extra hooks for startup, finalize, and exception handling.
        """
　　　　 # 将args与kwargs保存在对象中, 并将传入的args与kwargs传入initialize_request函数中
        self.args = args
        self.kwargs = kwargs
　　     # 返回的是一个Request对象,对request封装, 以后使用的request都是封装之后的request, 原生的request在request._request中
        request = self.initialize_request(request, *args, **kwargs)
　　     # 将request保存在对象中
        self.request = request
        # 不知道有啥用, 该函数没用到
        self.headers = self.default_response_headers  # deprecate?

        try:
            # 
            self.initial(request, *args, **kwargs)

            # Get the appropriate handler method
            # 与django.views.View中的一样
            if request.method.lower() in self.http_method_names:
                handler = getattr(self, request.method.lower(),
                                  self.http_method_not_allowed)
            else:
                handler = self.http_method_not_allowed

            response = handler(request, *args, **kwargs)

        except Exception as exc:
            response = self.handle_exception(exc)

        self.response = self.finalize_response(request, response, *args, **kwargs)
        return self.response

APIView中initialize_request

    def initialize_request(self, request, *args, **kwargs):
        """
        Returns the initial request object.
        """
        parser_context = self.get_parser_context(request)

        # 将request封装,并返回该对象
        return Request(
            request,
            parsers=self.get_parsers(),
            authenticators=self.get_authenticators(),
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

 APIView中的inititial

    def initial(self, request, *args, **kwargs):
        """
        Runs anything that needs to occur prior to calling the method handler.
        """
　　     # 判断是否设置了FORMAT_SUFFIX_KWARG, 设置了就将它保存, 没设置则为空
        self.format_kwarg = self.get_format_suffix(**kwargs)

        # 分页相关,暂不看
        # Perform content negotiation and store the accepted info on the request
        neg = self.perform_content_negotiation(request)
        request.accepted_renderer, request.accepted_media_type = neg


        # 版本相关, 暂不看　　
        # Determine the API version, if versioning is in use.
        version, scheme = self.determine_version(request, *args, **kwargs)
        request.version, request.versioning_scheme = version, scheme

        # Ensure that the incoming request is permitted
        # 认证, 权限, 频率
        self.perform_authentication(request)  # 认证通过之后再往下走
        self.check_permissions(request)  # 查看你有没有权限
        self.check_throttles(request)  # 进入的次数

 

Request类：
   -1 原生的request是self._request
   -2 取以post形式提交的数据，从request.data中取（urlencoded，formdata，json格式）
   -3 query_params 就是原生request的GET的数据
   -4 上传的文件是从FILES中取
   -5 其他的属性，直接request.属性名（因为重写了__getattr__方法）