使用 GAE 的服务器端流身份验证失败

Question

我想在我的 GAE 项目上实现服务器端流身份验证。

首先，我将用户重定向到 OAuth 对话框以获取代码。

然后我尝试使用这些代码来验证我的应用程序（我替换敏感部分）：

code = self.request.get('code')
url = 'https://graph.facebook.com/oauth/access_token?client_id=00000000000000&redirect_uri=http://000000000000.com/&client_secret=00000000&code=' + code
response = urllib2.urlopen(url)
content = response.read()

并且我认为我可以在内容变量中获取访问令牌和过期时间，

但我得到的只是错误消息：

Traceback (most recent call last):
  File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/_webapp25.py", line 701, in __call__
    handler.get(*groups)
  File "/base/data/home/apps/s~livingtomato/1.353914368655529058/main.py", line 28, in get
    response = urllib2.urlopen(url)
  File "/base/python_runtime/python_dist/lib/python2.5/urllib2.py", line 124, in urlopen
    return _opener.open(url, data)
  File "/base/python_runtime/python_dist/lib/python2.5/urllib2.py", line 387, in open
    response = meth(req, response)
  File "/base/python_runtime/python_dist/lib/python2.5/urllib2.py", line 498, in http_response
    'http', request, response, code, msg, hdrs)
  File "/base/python_runtime/python_dist/lib/python2.5/urllib2.py", line 425, in error
    return self._call_chain(*args)
  File "/base/python_runtime/python_dist/lib/python2.5/urllib2.py", line 360, in _call_chain
    result = func(*args)
  File "/base/python_runtime/python_dist/lib/python2.5/urllib2.py", line 506, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
HTTPError: HTTP Error 404: Not Found

这真的很奇怪，因为如果我打印url变量并直接用浏览器链接到url，我可以成功获取访问令牌和过期时间！

我真的很困惑。有人可以帮助我吗？

谢谢！我很抱歉我的英语不好。