string(230) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%AE%80%E8%BF%B0%E9%80%9F%E5%8D%96%E9%80%9A%E7%9A%84%E4%BC%98%E7%BC%BA%E7%82%B9 => Received HTTP code 403 from proxy after CONNECT"
简述速卖通的优缺点
