while urllib following the redirection(302):
http.client.HTTPConnection.putrequest raise an error:
#----------------------------------------------------------
...
  File "D:\Program Files\Python32\lib\http\client.py", line 1004, in _send_request
    self.putrequest(method, url, **skips)
  File "D:\Program Files\Python32\lib\http\client.py", line 868, in putrequest
    self._output(request.encode('ascii'))
UnicodeEncodeError: 'ascii' codec can't encode characters in position 108-111: ordinal not in range(128)
#----------------------------------------------------------
in the sourcode i found that:
at line 811

def putrequest(self, method, url, skip_host=0,skip_accept_en...)
...

the argument url may be a unicode,and it was unquoted..
----------------------------note----------------------------------------
in my case:
...
purl="http://bbs.dospy.com/1111258attachdown.php?aid=14361277&bbsid=349"
req=urllib.request.Request(purl,headers=headers)
response=urllib.request.urlopen(req)
...

then,the http serve redirect me to a file download url...
and the url contains some Chinese word....
i have print out the argument url:

/f/1ba1f70606223af2aa5c3aeff6c6a46a/511f7b4c/day_111015/20111015_5949e996881b2e28403d26Ch6dOfj6LZ.rar/p/ÒâÁÖ03-08.part1.rar