使用Scrapy_Proxies随机IP代理插件
https://github.com/aivarsk/scrapy-proxies

安装：

pip install scrapy_proxies

设置settings.py：

# Retry many times since proxies often fail
RETRY_TIMES = 10
# Retry on most error codes since proxies fail for different reasons
RETRY_HTTP_CODES = [500, 503, 504, 400, 403, 404, 408]

DOWNLOADER_MIDDLEWARES = {
    'scrapy.downloadermiddlewares.retry.RetryMiddleware': 90,
    'scrapy_proxies.RandomProxy': 100,
    'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 110,
}

# Proxy list containing entries like
# http://host1:port
# http://username:password@host2:port
# http://host3:port
# 这是存放代理IP列表的位置
PROXY_LIST = '/path/to/proxy/list.txt'

#代理模式
# 0 = Every requests have different proxy
# 1 = Take only one proxy from the list and assign it to every requests
# 2 = Put a custom proxy to use in the settings
PROXY_MODE = 0

#如果使用模式2，将下面解除注释：
#CUSTOM_PROXY = "http://host1:port"

使用方法：

1. 将之前用Python爬到的代理IP列表存储到PROXY_LIST可以找到的位置；
2. 几种PROXY_MODE里，可能0是最常用的；如果有哪个IP是特别稳定的话，应该使用2。

最关键的还是维护一个高可用的IP代理池。