serf doesn't support SSL tunneling over HTTP proxies

[GoogleCodeExporter]

Can be reproduced with subversion.

What steps will reproduce the problem?
1. setup an http proxy
2. use svn+serf, do:
   svn ls https://svn.collab.net/repos/svn/trunk/

What is the expected output? What do you see instead?
The command should show the contents of the trunk dir in the svn repo. 
Instead, svn returns a serf error:
subversion/svn/list-cmd.c:284: (apr_err=20014)
subversion/libsvn_client/list.c:138: (apr_err=20014)
subversion/libsvn_client/ra.c:492: (apr_err=20014)
subversion/libsvn_ra/ra_loader.c:481: (apr_err=20014)
subversion/libsvn_ra/ra_loader.c:481: (apr_err=20014)
subversion/libsvn_ra_serf/options.c:472: (apr_err=20014)
subversion/libsvn_ra_serf/util.c:563: (apr_err=20014)
svn: Error running context: Internal error

To connect to a HTTPS server over a HTTP proxy, serf should use a 'HTTP
CONNECT' request to the proxy. This isn't implemented in serf, so now it
finds the address of the proxy server and directly tries to open a SSL
connection. 

This was originally reported on the svn-dev mailing list here:
http://svn.haxx.se/dev/archive-2009-06/0238.shtml
(don't bother reading the responses to the first mail, there's only
irrelevant noise there).

Original issue reported on code.google.com by lieven.govaerts@gmail.com on 8 Jul 2009 at 10:36

[GoogleCodeExporter]

This issue is currently considered a blocker for Serf being the default HTTP 
library used by Subversion.  See corresponding Subversion issue no. 3891: 
http://subversion.tigris.org/issues/show_bug.cgi?id=3891

Original comment by cmpilato on 27 May 2011 at 5:51

[GoogleCodeExporter]

Original comment by lieven.govaerts@gmail.com on 5 Jun 2011 at 8:05

• Changed state: Started

[GoogleCodeExporter]

Fixed in r1474. One TODO left in the code and testing needed (especially with 
authenticating proxies and on non-mac platforms).

Original comment by lieven.govaerts@gmail.com on 5 Jun 2011 at 9:21

• Changed state: Fixed