$Django cbv源码分析 djangorestframework框架之APIView源码分析

1 CBV的源码分析

#视图
class login (View):
    pass
#路由
url(r'^books/$', views.login.as_view())

#阅读源码:
#左侧工程栏--->设置图标-->点击--->show members(能看到py文件,pu下的类，类下的方法)
-Class Base View(基于类的视图)
    -Function Base View(基于函数的视图)
    -def as_view 类方法 :返回view
    -def view:as_view的内的函数(闭包)
    -python中一切皆对象:函数也是对象
    -hasattr(self, 'get')--判断self类中是不是有该(get)方法  
    -setattr(self,get,get_all):相当于把get函数,变成了get_all 
    -getattr(self, 'get'):拿到get函数的内存地址
    - def view(request, *args, **kwargs):
        self = cls(**initkwargs)
        if hasattr(self, 'get') and not hasattr(self, 'head'):
            self.head = self.get
        self.request = request
        self.args = args
        self.kwargs = kwargs
        #执行:dispatch:谁的dispatch方法?写的cbv的那个c,视图中的那个视图类
        #我这个类如果没有写dispatch,会执行View中的dispatch方法
        return self.dispatch(request, *args, **kwargs)
    -def dispatch(self, request, *args, **kwargs):
        #request.method 前台请求的方法,转成了小写
        #http_method_names View中定义的一个列表:是一堆请求方式
        if request.method.lower() in self.http_method_names:
            #getattr的第三个参数是默认值:self.http_method_not_allowed
            #拿到get方法的内存地址
            handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
        else:
            handler = self.http_method_not_allowed
        #get(request,*args, **kwargs)
        return handler(request, *args, **kwargs

　总结:*******请求来了--->as_view---->view---->dispatch--->分发到不同的函数,执#行函数,拿到结果

 2 djangorestframework框架

   安装:djangorestframework
　　 -它是一个app,要在咱的项目中用
　　 -只是快速的构建resful规范的接口
　　 -csrf_exempt:局部禁用csrf(csrf是可以局部使用,局部禁用)
 　　-以后再执行的dispatch方法是APIView的dispatch方法
　　 -getattr和setattr
   重点掌握这三点:
 　　 -request.data 是个方法,包装成了属性,前台传过来body体中数据的数据,放在里面
 　　 -request.query_params  这个是原来GET中的数据
 　　 -request把原来的request包装进去了

3  APIView源码分析

 @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.
        """
        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

        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.
        return csrf_exempt(view)

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.
        """
        self.args = args
        self.kwargs = kwargs
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?

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

            # Get the appropriate handler method
            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):
        """
        Returns the initial request object.
        """
        parser_context = self.get_parser_context(request)

        return Request(
            request,
            parsers=self.get_parsers(),
            authenticators=self.get_authenticators(),
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

def initial(self, request, *args, **kwargs):
        """
        Runs anything that needs to occur prior to calling the method handler.
        """
        self.format_kwarg = self.get_format_suffix(**kwargs)

        # 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

        # 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
        self.perform_authentication(request)
        self.check_permissions(request)
        self.check_throttles(request)

 总结:*******请求来了--->as_view---->view---->dispatch（apiview的比上面的多做了  包了个request对象生成新的request对象  和调用initial方法 都是apiview自己的方法）--->分发到不同的函数,执#行函数,拿到结果