drf源码剖析----request

源码解析：
#  请求函数内的request，*args, **kwargs传给父类APIView内的dispatch()函数
    def dispatch(self, request, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs
# request，*args, **kwargs传给self.initialize_request(request, *args, **kwargs)进行封装
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?

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

            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

    def initialize_request(self, request, *args, **kwargs):
        parser_context = self.get_parser_context(request)
# 将request传给类Request()
        return Request(
            request,
            parsers=self.get_parsers(),
            authenticators=self.get_authenticators(),
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

class Request:

    def __init__(self, request, parsers=None, authenticators=None,
                 negotiator=None, parser_context=None):
        assert isinstance(request, HttpRequest), (
            .format(request.__class__.__module__, request.__class__.__name__)
        )
        # 原装的request封装为self._request
        self._request = request

# __getattr__当调用的对象的属性不存在时触发
# __getattribute__无论调用对象的属性是否存在，都会执行该函数

class HttpRequest(object):

    def __init__(self):
        pass

    def f1(self):
        print('f1')

    def f2(self):
        print('f2')


class Request(object):

    def __init__(self, req, m):
        self._request = req   # 此处见源码解析
        self.m = m
        print(self.args)  
        print(self.kwargs)
    
    def __getattr__(self, item):   # 2.Request中不存在f1, 执行__getattr__
        try:                   # 3.如果HttpRequest中存在f1,继续执行
            return getattr(self._request, item)  
        except AttributeError:
            return self.__getattribute__(item)
            #  3.如果HttpRequest中不存在f1，继续在Request中寻找f1，没有则报错


httprequest = HttpRequest()
httprequest.f1()
httprequest.f2()

# 将实例化对象httprequest以参数形式传给Request()
request = Request(httprequest, 123)   
request._request.f1()  # 此处见源码解析
request.f1()   # 1. 函数开始执行

结果：
f1
f2
f1
f1