scrapy 中异常处理的中间件如何调用

Question

import time,random

from scrapy.downloadermiddlewares.retry import RetryMiddleware


class processallexceptionmiddleware(RetryMiddleware):


    def process_response(self, request, response, spider):
        # 捕获状态码为40x/50x的response
        if str(response.status).startswith('4') or str(response.status).startswith('5')or str(response.status).startswith('3'):
            print('报错的是4和5 3开头的重新请求')
            return request
        if 'forbidden' in response.url:
            return request
        return response



    def process_exception(self, request, exception, spider):
        # 捕获几乎所有的异常
        if isinstance(exception, self.EXCEPTIONS_TO_RETRY):
            print('打印异常')
            # 在日志中打印异常类型
            print('Got exception: %s' % (exception))
            # 随意封装一个response，返回给spider
            time.sleep(random.randint(3, 5))
            return request


 custom_settings = {
        "RANDOM_DELAY": 20,
        'DOWNLOADER_MIDDLEWARES': {
            'Espider.middlewares.proxymiddleware.proxy_middleware': 543,
            "Espider.middlewares.processallexceptionmiddleware.processallexceptionmiddleware": 544

        },

我这样处理后，没有调用，求人指教，谢谢 我用了日志功能 记录爬虫的行为