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Title: urllib2 cannot handle https with proxy requiring auth
Type: Stage: needs patch
Components: Library (Lib) Versions: Python 3.10, Python 3.9, Python 3.8, Python 3.7, Python 3.6, Python 3.5, Python 2.7
Status: open Resolution: accepted
Dependencies: Superseder:
Assigned To: orsenthil Nosy List: Jessica Ridgley, alexey.namyotkin, b.a.scott, dieresys, martin.panter, mbeachy, orsenthil, ronaldoussoren, tsujikawa, vzafzal, yan12125
Priority: normal Keywords: patch

Created on 2009-11-09 04:38 by tsujikawa, last changed 2022-04-11 14:56 by admin.

File name Uploaded Description Edit
https_proxy_auth.patch tsujikawa, 2009-11-09 06:56 patch to send Proxy-Authorization header in CONNECT method(https proxy) review dieresys, 2009-12-23 22:16
2_7_x.patch mbeachy, 2011-02-19 17:23 2.7 maintenance branch patch review mbeachy, 2011-02-19 17:25 2.6.4 monkey patch
urllib2_tests.tar.gz b.a.scott, 2011-02-21 11:09 Test code, results and instructions
http_proxy_https.patch b.a.scott, 2011-02-21 11:19 Fix handling of 407 and 401 in urllib2 and httplib review vzafzal, 2014-02-21 13:45
Messages (24)
msg95058 - (view) Author: Tatsuhiro Tsujikawa (tsujikawa) Date: 2009-11-09 04:38
urllib2 cannot handle https with proxy requiring authorization.

After https_proxy is set correctly,

Python 2.6.4 (r264:75706, Oct 29 2009, 15:38:25)
[GCC 4.4.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import urllib2
>>> c=urllib2.urlopen("")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/", line 124, in urlopen
    return, data, timeout)
  File "/usr/lib/python2.6/", line 389, in open
    response = self._open(req, data)
  File "/usr/lib/python2.6/", line 407, in _open
    '_open', req)
  File "/usr/lib/python2.6/", line 367, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.6/", line 1154, in https_open
    return self.do_open(httplib.HTTPSConnection, req)
  File "/usr/lib/python2.6/", line 1121, in do_open
    raise URLError(err)
urllib2.URLError: <urlopen error Tunnel connection failed: 407 Proxy
Authentication Required>

This is because HTTPConnection::_tunnel() in doesn't send
Proxy-Authorization header.
msg95060 - (view) Author: Tatsuhiro Tsujikawa (tsujikawa) Date: 2009-11-09 06:56
I created a patch.
I added additional argument 'headers' to HTTPConnection::set_tunnel()
which is a mapping of HTTP headers to sent with CONNECT method. Since
credential is already set to Request object, in
if "Proxy-Authorization" header is found, pass it to set_tunnel().

It works fine for me.
msg95373 - (view) Author: Ronald Oussoren (ronaldoussoren) * (Python committer) Date: 2009-11-17 10:40
The patch looks good to me.

IMHO this should be backported to 2.6 as well.
msg95377 - (view) Author: Ronald Oussoren (ronaldoussoren) * (Python committer) Date: 2009-11-17 10:52
I've tested a backport of the patch to 2.6 (just replace set_proxy by 
_set_proxy in the patch) and the resulting version of urllib2 can login to 
the proxy (as expected).

Thanks for the patch.
msg96659 - (view) Author: Senthil Kumaran (orsenthil) * (Python committer) Date: 2009-12-20 06:05
Fixed and Committed revision 76908 in the trunk.
msg96660 - (view) Author: Senthil Kumaran (orsenthil) * (Python committer) Date: 2009-12-20 07:22
Fixed through reversions r76908, r76909, r76910, r76911

Thanks for the patch, Tatsuhiro Tsujikawa.
msg96661 - (view) Author: Senthil Kumaran (orsenthil) * (Python committer) Date: 2009-12-20 07:22
meant revisions.
msg96844 - (view) Author: Manuel Muradás (dieresys) Date: 2009-12-23 22:11
Hi! 2.6 backport is missing an argument in _set_tunnel definition. It
should be:

    def _set_tunnel(self, host, port=None, headers=None):
msg96845 - (view) Author: Manuel Muradás (dieresys) Date: 2009-12-23 22:16
The patch fixes only when you pass the authentication info in the proxy
handler's URL. Like:

    proxy_handler = urllib2.ProxyHandler({'https':

But setting the authentication using a ProxyBasicAuthHandler is still

    proxy_auth_handler = urllib2.ProxyBasicAuthHandler()
    proxy_auth_handler.add_password('realm', '',
'user', 'pass')

In the attached file ( we've wrote
a comparison between what works with HTTP and HTTPS.

The problem is the 407 error never reaches the ProxyBasicAuthHandler
because HTTPConnection._tunnel raises an exception when the http
response status code is not 200.
msg96846 - (view) Author: Senthil Kumaran (orsenthil) * (Python committer) Date: 2009-12-24 00:53
Thanks for the note, Manuel. Fixed it in revision 77013.
msg100840 - (view) Author: Senthil Kumaran (orsenthil) * (Python committer) Date: 2010-03-11 09:31
In this ticket, setting the authentication using a ProxyBasicAuthHandler is not yet addressed yet. (this was informed in the last note). Reopening this one to track it.
msg103090 - (view) Author: Mike Beachy (mbeachy) Date: 2010-04-13 23:11
I have worked up a monkey patch for urllib2/httplib for the issue of setting the authentication using a Proxy(Basic|Digest)AuthHandler.

The basic approach was to create a new httplib exception (ProxyTunnelError) and raise that with the http response attached so that the HTTPSHandler can determine when 407 Proxy authentication required is present, and then reroute the urllib2.OpenerDirector to error handling mode.

Unfortunately, there is a backwards compatibility issue - cases where a socket.error was previously being raised now get an ProxyTunnelError. Not that you could do much useful with the socket.error in the first place, but I suppose you could look for '407' in the text. Ugh.

If you think this might prove useful, let me know and I can rework it into a real patch - just let me know what branch/version to base it off of. (My monkey patch is for python 2.6.4.)
msg128861 - (view) Author: Mike Beachy (mbeachy) Date: 2011-02-19 17:23
I've been in contact w/ Barry Scott offline re: the monkey patch previously mentioned. I'm attaching a 2.7 maintenance branch patch that he has needed to extend, and plans to follow up on.
msg128862 - (view) Author: Mike Beachy (mbeachy) Date: 2011-02-19 17:25
Attached to this comment (can you attach multiple files at once?) is the somewhat moldy 2.6.4 monkey patch, mercilessly ripped from my own code and probably not good for much.
msg128952 - (view) Author: Barry Scott (b.a.scott) Date: 2011-02-21 10:41
The attached patch builds on Mike's work.

The core of the problem is that the Request object
did not know what was going on. This means that it
was not possible for get_authorization() to work
for proxy-auth and www-auth.

I change Request to know which of the four types of
connection it represents. There are new methods on
Request that return the right information based on
the connection type.

To understand how to make this work I needed to
instrument the code. There is now a set_debuglevel
on the OpenerDirector object that turns on debug in
all the handlers and the director. I have added
more debug messages to help understand this code.

This code now passes the 72 test cases I run. I'll
attach the code I used to test as a follow up to this.
msg128953 - (view) Author: Barry Scott (b.a.scott) Date: 2011-02-21 11:09
Attached is the code I used to test these changes.
See the README.txt file for details include
the results of a test run.
msg128955 - (view) Author: Barry Scott (b.a.scott) Date: 2011-02-21 11:19
I left out some white space changes to match the style
of the std lib code. Re posting with white space cleanup.
msg211850 - (view) Author: Vackar Afzal (vzafzal) Date: 2014-02-21 11:40
I've found that for the Python2.6.x patch to play nicely with the popular rquests library, I've had to set some defaults on the modified __init__ function so that it reads as follows:

    def __init__(self, *args, **kwargs):
        _orig_init(self, *args, **kwargs)
        self._tunnel_headers = {}
        self._tunnel_host = ''
        self._tunnel_port = ''

Also seems to work with python 2.6.1. Note: Change the entry condition to:

if os.environ.get('https_proxy', None) and sys.version_info[:2]  == (2, 6) :
msg211860 - (view) Author: Vackar Afzal (vzafzal) Date: 2014-02-21 13:45
Also needed to make another minor update to the monkey patch.
Have uploaded the new files as for use with python 2.6.x
msg228406 - (view) Author: Mark Lawrence (BreamoreBoy) * Date: 2014-10-03 22:49
Is there any work still needed here?  Surely the 2.6.x patches can't be applied unless there are security issues?
msg244513 - (view) Author: Martin Panter (martin.panter) * (Python committer) Date: 2015-05-31 03:57
I believe this also affects Python 3; see Issue 24333.

I think making the CONNECT response object available to the caller is the right general approach. But I really dislike raising an exception that holds a socket connection to be closed. (I know this is already done with urllib.error.HTTPError; let’s not repeat this in the “http.client” module!)

Ideally, at the “http.client” level I would prefer to avoid all the special set_tunnel() calls, and use the usual request() and getresponse() API to make the CONNECT request. This way the response status and header fields would be available just like any other response. For this approach to work, we would probably need to add a new HTTPConnection.detach() method that released the original socket reader and writer, and add a way to create a new HTTPConnection instance using these socket objects. This enhancement probably wouldn’t be appropriate for Python 2 or a bug fix release. But it seems the cleanest approach to me, and may also allow using HTTPConnection with the Upgrade header (e.g. for opportunistic encryption, HTTP 2, Web etc), and proxying non-HTTP connections, as bonuses.

A less revolutionary approach might be to add a HTTPSConnection.tunnel() method, that always returns the proxy’s response, but only does the SSL wrapping for a successful response.
msg247805 - (view) Author: Martin Panter (martin.panter) * (Python committer) Date: 2015-08-01 10:14
For the record, a while ago I think I made a patch implementing my HTTPConnection.detach() proposal. I can probably dig it up if anyone is interested.

However I gave up on fixing this bug in “urllib.request”. As far as I understand it, the framework does not distinguish the 407 Proxy Authentication Required error of the initial proxy CONNECT request from any potential 407 response from a tunnelled connection. Perhaps a special case could be made; I think there are already lots of special cases. But the maze of urlopen() handlers is already too complicated and I decided this was too hard to bother working on. Sorry :)
msg283306 - (view) Author: Chih-Hsuan Yen (yan12125) * Date: 2016-12-15 14:00
Modify target versions to bugfix and feature branches
msg374687 - (view) Author: Alexey Namyotkin (alexey.namyotkin) * Date: 2020-08-02 19:06
It has been 5 years, now the urllib3 is actively used, but it also inherited this problem: if no authentication data has been received, then the method _tunnel raises an exception OSError that does not contain response headers. Accordingly, this exception cannot be handled. And perhaps this is an obstacle to building a convenient system of authentication on a proxy server in a widely used library requests (it would be nice to be able to just provide an argument proxy_auth, similar to how it is done for server authorization). Now, if a user wants to send a https request through a proxy that requires complex authentication (Kerberos, NTLM, Digest, other) using the urllib3, he must first send a separate request to the proxy, receive a response, extract the necessary data to form the header Proxy-Authorization, then generate this header and pass it to the ProxyManager. And if we are talking about Requests, then the situation there is worse, because you cannot pass proxy headers directly (
If we were to aim to simplify the authentication procedure on the proxy server for the user, then where would we start, do we need to change the http.client so that the error returned by the method _tunnel contains headers? Or maybe it's not worth changing anything at all and the path with preliminary preparation by user of the header Proxy-Authorization is the only correct one? Martin Panter, could you also give your opinion? Thank you in advance.
Date User Action Args
2022-04-11 14:56:54adminsetgithub: 51540
2020-08-02 19:06:17alexey.namyotkinsetmessages: + msg374687
2020-07-29 15:36:59Jessica Ridgleysetnosy: + Jessica Ridgley

versions: + Python 3.8, Python 3.9, Python 3.10
2020-07-29 14:46:07alexey.namyotkinsetnosy: + alexey.namyotkin
2016-12-15 14:58:30BreamoreBoysetnosy: - BreamoreBoy
2016-12-15 14:00:36yan12125setmessages: + msg283306
versions: + Python 3.7, - Python 2.6, Python 3.4
2015-12-11 07:25:49yan12125setnosy: + yan12125
2015-08-01 10:14:33martin.pantersetmessages: + msg247805
stage: needs patch
2015-05-31 04:00:10martin.panterlinkissue24333 superseder
2015-05-31 03:57:45martin.pantersetnosy: + martin.panter

messages: + msg244513
versions: + Python 3.4, Python 3.5, Python 3.6
2014-10-03 22:49:46BreamoreBoysetnosy: + BreamoreBoy
messages: + msg228406
2014-02-21 13:45:45vzafzalsetfiles: +

messages: + msg211860
2014-02-21 11:40:19vzafzalsetnosy: + vzafzal
messages: + msg211850
2011-02-21 11:19:31b.a.scottsetfiles: - http_proxy_https.patch
nosy: ronaldoussoren, orsenthil, mbeachy, dieresys, tsujikawa, b.a.scott
2011-02-21 11:19:23b.a.scottsetfiles: + http_proxy_https.patch
nosy: ronaldoussoren, orsenthil, mbeachy, dieresys, tsujikawa, b.a.scott
messages: + msg128955
2011-02-21 11:09:42b.a.scottsetfiles: + urllib2_tests.tar.gz
nosy: ronaldoussoren, orsenthil, mbeachy, dieresys, tsujikawa, b.a.scott
messages: + msg128953
2011-02-21 10:41:27b.a.scottsetfiles: + http_proxy_https.patch
nosy: + b.a.scott
messages: + msg128952

2011-02-19 17:25:17mbeachysetfiles: +
nosy: ronaldoussoren, orsenthil, mbeachy, dieresys, tsujikawa
messages: + msg128862
2011-02-19 17:23:26mbeachysetfiles: + 2_7_x.patch
nosy: ronaldoussoren, orsenthil, mbeachy, dieresys, tsujikawa
messages: + msg128861
2010-04-13 23:11:40mbeachysetnosy: + mbeachy
messages: + msg103090
2010-03-11 09:31:44orsenthilsetstatus: closed -> open
resolution: fixed -> accepted
messages: + msg100840
2010-02-22 16:13:43floxlinkissue7986 superseder
2009-12-24 00:53:30orsenthilsetmessages: + msg96846
2009-12-23 22:16:00dieresyssetfiles: +

messages: + msg96845
2009-12-23 22:11:04dieresyssetnosy: + dieresys
messages: + msg96844
2009-12-20 07:22:49orsenthilsetmessages: + msg96661
2009-12-20 07:22:10orsenthilsetstatus: open -> closed

messages: + msg96660
2009-12-20 06:06:00orsenthilsetkeywords: - needs review
resolution: accepted -> fixed
messages: + msg96659
2009-11-17 10:52:27ronaldoussorensetmessages: + msg95377
2009-11-17 10:40:36ronaldoussorensetkeywords: + needs review
nosy: + ronaldoussoren
messages: + msg95373

2009-11-15 09:21:35orsenthilsetassignee: orsenthil

resolution: accepted
nosy: + orsenthil
2009-11-11 01:06:09tsujikawasetversions: + Python 2.7
2009-11-09 06:56:13tsujikawasetfiles: + https_proxy_auth.patch
keywords: + patch
messages: + msg95060
2009-11-09 04:38:16tsujikawacreate