scrapy 中间件设置随机UA、随机cookie、以及代理

在Scrapy中设置随机的User-Agent (UA)、随机cookie 以及使用代理的方法如下：

1. 随机UA中间件：

首先，创建一个Scrapy中间件，用于随机设置请求的User-Agent。

# middlewares.py
 
from scrapy import signals
 
class RandomUserAgentMiddleware:
    def __init__(self, user_agent=''):
        self.user_agent = user_agent
 
    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            user_agent=crawler.settings.get('RANDOM_UA_LIST')
        )
 
    def process_request(self, request, spider):
        user_agent = random.choice(self.user_agent)
        request.headers.setdefault('User-Agent', user_agent)

在Scrapy设置文件 (settings.py) 中启用并配置这个中间件，以及UA列表：

# settings.py
 
DOWNLOADER_MIDDLEWARES = {
    'your_project.middlewares.RandomUserAgentMiddleware': 400,
}
 
RANDOM_UA_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",
    ...
]

2. 随机cookie中间件：

# middlewares.py
 
class RandomCookieMiddleware:
    def __init__(self, cookie_list=None):
        self.cookie_list = cookie_list or []
 
    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            cookie_list=crawler.settings.getlist('RANDOM_COOKIE_LIST')
        )
 
    def process_request(self, request, spider):
        cookie = random.choice(self.cookie_list)
        request.cookies = cookie

在设置文件中配置cookie列表和启用中间件：

# settings.py
 
COOKIES_ENABLED = True
 
RANDOM_COOKIE_LIST = [
    {'name': 'value'},
    {'name2': 'value2'},
    ...
]
 
DOWNLOADER_MIDDLEWARES = {
    'your_project.middlewares.RandomCookieMiddleware': 401,
}

3. 使用代理中间件：

# middlewares.py
 
class ProxyMiddleware:
    def __init__(self, proxy_url=''):
        self.proxy_url = proxy_url
 
    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            proxy_url=crawler.settings.get('PROXY_URL')
        )
 
    def process_request(self, request, spider):
        request.meta['proxy'] = self.proxy_url

在设置文件中配置代理URL和启用中间件：

# settings.py
 
PROXY_URL = 'http://user:pass@proxy.example.com:8080'
 
DOWNLOADER_MIDDLEWARES = {
    'your_project.middlewares.ProxyMiddleware': 410,
}
``