hgweb.cgi

sslutil: improve messaging around unsupported protocols (issue5303)

There are various causes for the inability to negotiate common SSL/TLS
protocol between client and server. Previously, we had a single, not
very actionable warning message for all of them.

As people encountered TLS 1.0 servers in real life, it was quickly
obvious that the existing messaging was inadequate to help users
rectify the situation.

This patch makes the warning messages much more verbose in hopes of
making them more actionable while simultaneously encouraging users
and servers to adopt better security practices.

This messaging flirts with the anti-pattern of "never blame the
user" by signaling out poorly-configured servers. But if we're going to
disallow TLS 1.0 by default, I think we need to say *something* or
people are just going to blame Mercurial for not being able to connect.
The messaging tries to exonerate Mercurial from being the at fault
party by pointing out the server is the entity that doesn't support
proper security (when appropriate, of course).

#!/usr/bin/env python
#
# An example hgweb CGI script, edit as necessary
# See also https://mercurial-scm.org/wiki/PublishingRepositories

# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = "/path/to/repo/or/config"

# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")

# Uncomment to send python tracebacks to the browser if an error occurs:
#import cgitb; cgitb.enable()

from mercurial import demandimport; demandimport.enable()
from mercurial.hgweb import hgweb, wsgicgi
application = hgweb(config)
wsgicgi.launch(application)