scrapy---反爬虫

反爬虫措施
1)动态修改User-Agent
2)动态修改ip
3)延迟DOWNLOAD_DELAY = 0.5

1)在middleware中新建一个类,从fake_useragent中导入UserAgent模块

from fake_useragent import UserAgent
class RandomUserAgentMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):

        return cls(crawler)

    def __init__(self,crawler):
        super(RandomUserAgentMiddleware,self).__init__()
        self.ua=UserAgent()

    def process_request(self, request, spider):

        request.headers.setdefault(b'User-Agent', self.ua.random)

    def spider_opened(self, spider):
        pass

在settings设置DOWNLOADER_MIDDLEWARES
先把系统自带的useragent禁用:None

DOWNLOADER_MIDDLEWARES = {
    'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None,
    'JobboleSpider.middlewares.RandomUserAgentMiddleware': 543,

}

2)动态修改ip

import random
class RandomProxyIPMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):

        return cls(crawler)

    def __init__(self, crawler):
        self.ip_list = [
            "http://180.125.196.155:8888",
             #ip代理
        ]

    def process_request(self, request, spider):

        request.meta['proxy']=random.choice(self.ip_list)


    def spider_opened(self, spider):
        pass

3)在settings中设置延迟

DOWNLOAD_DELAY = 0.5