scrapy user-agent随机更换

user-agent大全页面：

https://fake-useragent.herokuapp.com/browsers/0.1.6

使用fake-useragent模块

模块github地址：https://github.com/hellysmile/fake-useragent

安装方法：

pip install fake-useragent

使用方法：

from fake_useragent import UserAgent
ua = UserAgent()

ua.ie
# Mozilla/5.0 (Windows; U; MSIE 9.0; Windows NT 9.0; en-US);
ua.msie
# Mozilla/5.0 (compatible; MSIE 10.0; Macintosh; Intel Mac OS X 10_7_3; Trident/6.0)'
ua['Internet Explorer']
# Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; GTB7.4; InfoPath.2; SV1; .NET CLR 3.3.69573; WOW64; en-US)
ua.opera
# Opera/9.80 (X11; Linux i686; U; ru) Presto/2.8.131 Version/11.11
ua.chrome
# Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.2 (KHTML, like Gecko) Chrome/22.0.1216.0 Safari/537.2'
ua.google
# Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/537.13 (KHTML, like Gecko) Chrome/24.0.1290.1 Safari/537.13
ua['google chrome']
# Mozilla/5.0 (X11; CrOS i686 2268.111.0) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.57 Safari/536.11
ua.firefox
# Mozilla/5.0 (Windows NT 6.2; Win64; x64; rv:16.0.1) Gecko/20121011 Firefox/16.0.1
ua.ff
# Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:15.0) Gecko/20100101 Firefox/15.0.1
ua.safari
# Mozilla/5.0 (iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5355d Safari/8536.25

# and the best one, random via real world browser usage statistic
ua.random

scrapy 自动切换方法：

编辑middlewares.py文件

from fake_useragent import UserAgent

# 新增一个类
class RandomUserAgentMidddlware(object):
    # 随机更换user-agent
    def __init__(self, crawler):
        super(RandomUserAgentMidddlware, self).__init__()
        self.ua = UserAgent()
        # 从配置文件读取随机类型
        self.ua_type = crawler.settings.get('RANDOM_UA_TYPE', 'random')

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler)

    def process_request(self, request, spider):
        # 通过配置文件的随机类型进行调用
        def get_ua():
            return getattr(self.ua, self.ua_type)

        request.headers.setdefault('User-Agent', get_ua())    

settings文件

DOWNLOADER_MIDDLEWARES = {
   # 将自己编写的类导入
   'ArticleSpider.middlewares.RandomUserAgentMidddlware': 543,
    # 导入系统自带的useragent类，并将优先级设置为none
    'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': None,
}

# 设置自定义的random的属性
RANDOM_UA_TYPE = "random"