New submission from Pietro Battiston:
If you run the following code:
#! /usr/bin/python
import urllib2
MyHTTPPasswordMgr = urllib2.HTTPPasswordMgr
proxy = urllib2.ProxyHandler({'http': 'http://proxybiblio2.si.unimib.it:8080'})
auth = urllib2.ProxyDigestAuthHandler(MyHTTPPasswordMgr())
auth.add_password(None, "proxybiblio2.si.unimib.it", "a", "b" )
opener = urllib2.build_opener(proxy, auth, urllib2.HTTPHandler)
urllib2.install_opener(opener)
conn = urllib2.urlopen('http://webofknowledge.com')
an "HTTP Error 407: Proxy Authentication Required" is raised, and under the
hood here's what's happening:
- the request is made without authentication
- the server replies it must be made with digest authentication, and gives the
nonce
- the error is raised.
Instead, urllib2 should now try to connect with the username and password, and
do so up to 5 times (as hardcoded in urllib2.http_error_auth_reqed), and then
raise a "HTTP Error 401: digest auth failed". And it's indeed what it does if
you replace the line "MyHTTPPasswordMgr = urllib2.HTTPPasswordMgr" with
class MyHTTPPasswordMgr(urllib2.HTTPPasswordMgr):
def find_user_password(self, realm, authuri):
return "a", "b"
So the problem is in HTTPPasswordMgr, which is apparently unable to match the
authentication data with the realm. Some tests¹ suggest that this can vary
according to the proxy engine and to the proxy address format (works with
apache, but doesn't if then you add "http://"; in front of the proxy address).
This reminds a bit bug 680577, and in particular I noticed that (possibly
unrelated) the behaviour reported in the following message:
http://bugs.python.org/msg14444
has not changed:
In [1]: import urllib2
In [2]: urllib2.HTTPPasswordMgr().is_suburi("/foo/spam", "/foo/eggs")Out[2]:
True
This affects also python 3.2, you can try the following:
#! /usr/bin/python
from urllib import request
MyHTTPPasswordMgr = request.HTTPPasswordMgr
proxy = request.ProxyHandler({'http': 'http://proxybiblio2.si.unimib.it:8080'})
auth = request.ProxyDigestAuthHandler(MyHTTPPasswordMgr())
auth.add_password(None, "proxybiblio2.si.unimib.it", "a", "b" )
opener = request.build_opener(proxy, auth, request.HTTPHandler)
request.install_opener(opener)
conn = request.urlopen('http://webofknowledge.com')
¹ http://lists.python.it/pipermail/python/2012-September/013309.html (in
Italian)
----------
components: Library (Lib)
messages: 171650
nosy: toobaz
priority: normal
severity: normal
status: open
title: urllib2 failing with squid proxy and digest authentication
type: behavior
versions: Python 2.7
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue16095>
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