UA池和ip代理池

UA池

背景

     我們在使用下載中間件處理請求,一般會對請求設置隨機的User-Agent,設置隨機的代理.目的就是防止爬取網站的反爬蟲策略,但是同一類型User-Agent的瀏覽器還是容易被監測到,開啟UA池放置更多類型的User-Agent就能夠極大避免反扒機制

作用

　　- 盡可能多的將scrapy工程中的請求偽裝成不同類型的瀏覽器身份

操作流程

• 在下載中間件中攔截請求
• 將攔截到的請求的請求頭信息中的UA進行篡改偽裝
• 在settings.py中開啟下載中間件

具體代碼

#導包
from scrapy.contrib.downloadermiddleware.useragent import UserAgentMiddleware
import random

#UA池代碼的編寫(單獨給UA池封裝一個下載中間件的一個類   )
class RandomUserAgent( UserAgentMiddleware):

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"
]

    def process_request(self,request,spider):
        #從列表中隨機抽取一個ua值
         ua = random.choice(user_agent_list)
        #ua值進行當前攔截到請求的ua的寫入操作
        request.headers.setdefault("User-Agent",ua)

 ip代理池

 作用

　　- 盡可能多的將scrapy工程中的請求的IP設置成不同的,防止被反扒策略封禁本機IP

操作流程

• 在下載中間件攔截請求
• 將攔截到的請求IP修改成某一代理ip
• 在settings.py中開啟下載中間件

具體代碼

"""批量對攔截到的請求進行ip更換"""
#單獨封裝下載中間件類

class Proxy(object):

#可被選用的代理IP
PROXY_http = [
    '126.120.102.124:80',
    '101.208.131.169:56055',
]
PROXY_https = [
    '20.83.49.90:900',
    '91.182.12.212:3508',
]
    
    def process_exception(self,request,spider):
        #針對攔截到的url進行判斷,(協議頭http/https的區分)
        #request.url 返回值處理為 http/https//:www.xxx.com
        h = request.url.split(':')[0]  #獲取請求頭協議
        if h == "https":
            ip.random.choice(Proxy_https)
            request.meta['proxy'] = 'https' + ip
        else:
            ip.random.choice(Proxy_http)
            request.meta['proxy'] = "http" + ip
　　　　　return request

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