scrapy 使用代理

# Importing base64 library because we'll need it ONLY#in case if the proxy we are going to use requires authenticationimport base64# Start your middleware classclass 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