在爬取网站内容的时候，最常遇到的问题是：网站对ip有限制，会有防抓取功能，最好的办法就是ip轮换抓取（加代理）
下面来说一下scrapy如何配置代理，进行抓取
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.在项目配置文件里(./pythontab/settings.py)添加
downloader_middlewares = {
‘scrapy.contrib.downloadermiddleware.httpproxy.httpproxymiddleware’: 110,
‘pythontab.middlewares.proxymiddleware’: 100,
}