Django之request进入中间件《二》

    def _get_response(self, request):
        """
        Resolve and call the view, then apply view, exception, and
        template_response middleware. This method is everything that happens
        inside the request/response middleware.
        """
        response = None

        if hasattr(request, 'urlconf'):
            urlconf = request.urlconf
            set_urlconf(urlconf)
            resolver = get_resolver(urlconf)
        else:
            resolver = get_resolver()
        resolver_match = resolver.resolve(request.path_info)
        callback, callback_args, callback_kwargs = resolver_match
        request.resolver_match = resolver_match

        for middleware_method in self._view_middleware:

            """
            <bound method
             CsrfViewMiddleware.process_view of 
             <django.middleware.csrf.CsrfViewMiddleware object at 0x034B1388>>
            """
            response = middleware_method(request, callback, callback_args, callback_kwargs)
            if response:
                break
        if response is None:
            wrapped_callback = self.make_view_atomic(callback)
            try:

                response = wrapped_callback(request, *callback_args, **callback_kwargs)
            except Exception as e:
                response = self.process_exception_by_middleware(e, request)

        # Complain if the view returned None (a common error).
        if response is None:
            if isinstance(callback, types.FunctionType):    # FBV
                view_name = callback.__name__
            else:                                           # CBV
                view_name = callback.__class__.__name__ + '.__call__'

            raise ValueError(
                "The view %s.%s didn't return an HttpResponse object. It "
                "returned None instead." % (callback.__module__, view_name)
            )

        # If the response supports deferred rendering, apply template
        # response middleware and then render the response
        elif hasattr(response, 'render') and callable(response.render):
            for middleware_method in self._template_response_middleware:
                response = middleware_method(request, response)
                # Complain if the template response middleware returned None (a common error).
                if response is None:
                    raise ValueError(
                        "%s.process_template_response didn't return an "
                        "HttpResponse object. It returned None instead."
                        % (middleware_method.__self__.__class__.__name__)
                    )

            try:
                response = response.render()
            except Exception as e:
                response = self.process_exception_by_middleware(e, request)
        return response

图解：

　　

     在执行完slef._get_response()后，程序会继续执行_middlware_chain 函数栈中的process_response

总结：关于中间件中的request/response