Python 2.7 HTTP基本身份验证

Question

也许有人能帮我。我正在尝试使用Python2.7和HTTP基本身份验证从网站获取数据。 该网站提供的唯一说明如下：

In order for your web service client to authenticate using basic authentication, the first HTTPS request must include the "Authorization" header specifying the account credentials to authenticate with. The header for a such a request would look like this:

  GET /polcs/trade.xml HTTP/1.0
  Host: secure.pol.com
  Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==

我尝试了几件事，但都不管用，例如：

import urllib2
import base64

b = base64.encodestring('USERNAME:PASSWORD').replace('\n', '')
conf = {'headers': {'GET': '/polcs/trade.xml HTTP/1.0', 'Authorization': 'Basic ' + b},
    'url': 'secure.pol.com'}
datas = None
request = urllib2.Request(conf['url'], datas, conf['headers'])
result = urllib2.urlopen(request)

这一个给了我HTTP错误403：

url = 'https://secure.pol.com/polcs/data.xml'
request = urllib2.Request(url)
b = base64.encodestring('USERNAME:PASSWORD').replace('\n', '')
request.add_header("Authorization", "Basic " + b)
result = urllib2.urlopen(request)

有人能告诉我，我在哪里获取数据会出错吗？ 谢谢大家!