python|python scrapy 防止爬虫被ban的策略 pythonscrapy防止爬虫被ban的策略

1、settings.py设置DOWNLOAD_DELAY
2、禁止cookies
在settings.py中设置COOKIES_ENABLES=False。也就是不启用cookies middleware，不想web server发送cookies。
3、使用user agent池
首先编写自己的UserAgentMiddle中间件，新建rotate_useragent.py,代码如下：
--coding:utf-8-- from scrapy import log
"""避免被ban策略之一：使用useragent池。
使用注意：需在settings.py中进行相应的设置。
"""
【python|python scrapy 防止爬虫被ban的策略】import random
from scrapy.contrib.downloadermiddleware.useragent import UserAgentMiddleware
class RotateUserAgentMiddleware(UserAgentMiddleware):

def __init__(self, user_agent=''): self.user_agent = user_agentdef process_request(self, request, spider): ua = random.choice(self.user_agent_list) if ua: #显示当前使用的useragent print "********Current UserAgent:%s************" %ua#记录 log.msg('Current UserAgent: '+ua, level='INFO') request.headers.setdefault('User-Agent', ua)#the default user_agent_list composes chrome,I E,firefox,Mozilla,opera,netscape #for more user agent strings,you can find it in http://www.useragentstring.com/pages/useragentstring.php user_agent_list = [\ "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 " "(KHTML, like Gecko) Chrome/22.0.1207.1 Safari/537.1", "Mozilla/5.0 (X11; CrOS i686 2268.111.0) AppleWebKit/536.11 " "(KHTML, like Gecko) Chrome/20.0.1132.57 Safari/536.11", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.6 " "(KHTML, like Gecko) Chrome/20.0.1092.0 Safari/536.6", "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.6 " "(KHTML, like Gecko) Chrome/20.0.1090.0 Safari/536.6", "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.1 " "(KHTML, like Gecko) Chrome/19.77.34.5 Safari/537.1", "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/536.5 " "(KHTML, like Gecko) Chrome/19.0.1084.9 Safari/536.5", "Mozilla/5.0 (Windows NT 6.0) AppleWebKit/536.5 " "(KHTML, like Gecko) Chrome/19.0.1084.36 Safari/536.5", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3", "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_0) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3", "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1062.0 Safari/536.3", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1062.0 Safari/536.3", "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3", "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 " "(KHTML, like Gecko) Chrome/19.0.1061.0 Safari/536.3", "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.24 " "(KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24", "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/535.24 " "(KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24" ]

建立user agent池（user_agent_list）并在每次发送request之前从agent池中随机选取一项设置request的User_Agent。编写的UserAgent中间件的基类为UserAgentMiddle。
除此之外，要在settings.py(配置文件)中禁用默认的useragent并启用重新实现的User Agent。配置方法如下：
取消默认的useragent,使用新的useragent DOWNLOADER_MIDDLEWARES = {
'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware' : None,
'CSDNBlogCrawlSpider.spiders.rotate_useragent.RotateUserAgentMiddleware' :400
}
4、使用IP池
可以使用Scrapy+Tor+polipo
5、