在爬取網站內容的時候，最常遇到的問題是：網站對IP有限制，會有防抓取功能，最好的方法就是IP輪換抓取（加代理）
下面來說一下Scrapy如何設定代理，進行抓取
1.在Scrapy工程下新建「middlewares.py」
# Importing base64 library because we'll need it ONLY in case if the proxy we are going to use requires authentication
import base64
# Start your middleware class
class ProxyMiddleware(object):
# overwrite process request
def process_request(self, request, spider):
# Set the location of the proxy
request.meta['proxy'] = "http://YOUR_PROXY_IP:PORT"
# Use the following lines if your proxy requires authentication
proxy_user_pass = "USERNAME:PASSWORD"
# setup basic authentication for the proxy
encoded_user_pass = base64.encodestring(proxy_user_pass)
request.headers['Proxy-Authorization'] = 'Basic ' + encoded_user_pass
2.在專案設定檔中(./pythontab/settings.
