GAE使用urllib2.urlopen出现DownloadError的问题

实验目的：
用flex在GAE上运行python代码
实验器材：
pyamf，FLEX3,Python25,IE，GAE SDK
实验准备：
GAE代码一份，flex代码一份
见下：
python部分
main.py

# -*- coding:utf-8 -*-   
import wsgiref.handlers  
import sys
import urllib2  
from google.appengine.ext import webapp  
from pyamf.remoting.gateway.google import WebAppGateway  
  
class MainPage(webapp.RequestHandler):  
    def get(self):  
        self.response.headers['Content-Type'] = 'text/plain'  
        self.response.out.write('Hello, webapp World!')  
  
def echo(data):
    p=urllib2.urlopen("http://www.sina.com.cn")
    return data
  
services = {  
    'myservice.echo': echo,  
}  
  
def main():  
    application_paths = [('/', WebAppGateway(services)), ('/helloworld', MainPage)]  
    application = webapp.WSGIApplication(application_paths, debug=True)  
    wsgiref.handlers.CGIHandler().run(application)  

flex部分

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="init();">
<mx:Script> 
	<![CDATA[ 
	import flash.net.*;
	import mx.controls.Alert;
	
	public function init():void{
		var netConnection:NetConnection = new NetConnection();
		netConnection.connect("http://localhost:8080/");
		var responder:Responder = new Responder(onComplete, onFail);
		netConnection.call("myservice.echo", responder, "Flash talked to PyAMF.  They both say hello.");
	}

	function onComplete(results):void {
		//var my:String = String("我就是中文");
		//var aTemp:Array = results as Array;
		//Alert.show(aTemp.toString());
		trace(results.toString());
		
		//trace(sTemp);
		
		/*for each(var thisResult in results){
        	trace(thisResult.toString());
  		}*/
	}

	function onFail(results):void {
        for each (var thisResult in results){
        	trace( thisResult);
        }
	}
]]> 
</mx:Script>
</mx:Application>

实验步骤：
1.打开CMD，用dev_appserver开启GAE服务器
2.在Flex中运行debug命令

实验问题：
['Traceback (most recent call last):', '  File "c:\\gaedemos\\cake\\pyamf\\remoting\\amf0.py", line 106, in __call__    *args, **kwargs)',
'  File "c:\\gaedemos\\cake\\pyamf\\remoting\\amf0.py", line 59, in _getBody    **kwargs)', '
File "c:\\gaedemos\\cake\\pyamf\\remoting\\gateway\\__init__.py", line 494, in callServiceRequest    return service_request(*args)',
'  File "c:\\gaedemos\\cake\\pyamf\\remoting\\gateway\\__init__.py", line 224, in __call__    return self.service(self.method, args)',
'  File "c:\\gaedemos\\cake\\pyamf\\remoting\\gateway\\__init__.py", line 125, in __call__    return func(*params)', '
File "c:\\gaedemos\\cake\\main.py", line 18, in echo    w.login(url)',
'  File "c:\\gaedemos\\cake\\webspy\\webspy.py", line 42, in login    myHome = urllib2.urlopen(request)',
'  File "C:\\Python25\\lib\\urllib2.py", line 124, in urlopen    return _opener.open(url, data)', ' 
File "C:\\Python25\\lib\\urllib2.py", line 381, in open    response = self._open(req, data)', '
File "C:\\Python25\\lib\\urllib2.py", line 399, in _open    \'_open\', req)', '  File "C:\\Python25\\lib\\urllib2.py", line 360, in _call_chain    result = func(*args)', '
File "C:\\Python25\\lib\\urllib2.py", line 1107, in http_open    return self.do_open(httplib.HTTPConnection, req)',
'  File "C:\\Python25\\lib\\urllib2.py", line 1080, in do_open    r = h.getresponse()', '
File "C:\\Program Files\\Google\\google_appengine\\google\\appengine\\dist\\httplib.py", line 200, in getresponse    self._allow_truncated, self._follow_redirects)', '
File "C:\\Program Files\\Google\\google_appengine\\google\\appengine\\api\\urlfetch.py", line 241, in fetch    return rpc.get_result(allow_truncated)'
, '  File "C:\\Program Files\\Google\\google_appengine\\google\\appengine\\api\\urlfetch.py", line 388, in get_result    self.check_success(allow_truncated)',
'  File "C:\\Program Files\\Google\\google_appengine\\google\\appengine\\api\\urlfetch.py", line 356, in check_success    raise DownloadError(str(e))'
, "DownloadError: ApplicationError: 2 nonnumeric port: ''"]
DownloadError
ApplicationError: 2 nonnumeric port: ''


问题初步分析：
最后给出的结果是非数字端口，于是我想是不是没写端口号啊。加上：80后依旧。python代码在Eclipse+pydev的环境下跑的好好的，怎么到了gae就不行了呢？在网上查了好久，看到如下链接： http://groups.google.co.jp/group/google-appengine/browse_thread/thread/07f418a36888c937
其中提到
This is a known incompatibility in App Engine. The GData APIs send an
absolute URL to the httplib library where it expects a relative one
(since the host and port was specified in the constructor); the Python
httplib handles this properly, but the App Engine replacement
currently does not.
奇怪的是python和GAE不是都用的一样的内核吗？我把python25的httplib文件复制过来以后还是这个问题。


实验小结：
问题期待继续调查。
发现一个解决的方法参见
http://nodex.iteye.com/blog/360733
参考了CPYUG组织，发现这是GAE的一个限制socket的行为，所以不管怎么改都没有用。可以用urlfetch代替，不过还困惑于cookie的处理。
可以参考：
https://groups.google.com/group/python-cn/browse_thread/thread/4b94c4ae8eb8d41c/54f2628668af75a0?lnk=gst&q=urlfetch#54f2628668af75a0

以后要多关注关注CPyUG了，真的好强啊。