-- 浏览器的同源策略 阻止ajax请求 不阻止src请求

    -- jsonp

        -- 我们利用src发送请求

    -- core

        -- class MyCore(MiddlewareMixin):

            def process_response(self, request, response):

                response['Access-Control-Allow-Origin'] = "*"

                if request.method == "OPTIONS":

                    # 复杂请求 预检

                    response['Access-Control-Allow-Headers'] = "Content-Type"

                    response['Access-Control-Allow-Methods'] = "POST, DELETE, PUT"

                return response