Error for emoji punycode domains

[dapetcu21]

My domain is https://🐈.cf, which translates to https://xn--zn8h.cf, which is apparently rejected by simp_le:

-----> Getting letsencrypt certificate for pisi...
- Domain 'pisi.petcu.me'
- Domain 'xn--zn8h.cf'
- Domain 'www.xn--zn8h.cf'
darkhttpd/1.12, copyright (c) 2003-2016 Emil Mikulic.
listening on: http://0.0.0.0:80/
Traceback (most recent call last):
File "/simp_le-master/simp_le.py", line 1401, in main
return main_with_exceptions(cli_args)
File "/simp_le-master/simp_le.py", line 1386, in main_with_exceptions
persist_new_data(args, existing_data)
File "/simp_le-master/simp_le.py", line 1300, in persist_new_data
challb.chall, name, client.key.public_key())
File "/usr/lib/python2.7/site-packages/acme/challenges.py", line 322, in simple_verify
http_response = requests.get(uri)
File "/usr/lib/python2.7/site-packages/requests/api.py", line 72, in get
return request('get', url, params=params, **kwargs)
File "/usr/lib/python2.7/site-packages/requests/api.py", line 58, in request
return session.request(method=method, url=url, **kwargs)
File "/usr/lib/python2.7/site-packages/requests/sessions.py", line 508, in request
resp = self.send(prep, **send_kwargs)
File "/usr/lib/python2.7/site-packages/requests/sessions.py", line 640, in send
history = [resp for resp in gen] if allow_redirects else []
File "/usr/lib/python2.7/site-packages/requests/sessions.py", line 218, in resolve_redirects
**adapter_kwargs
File "/usr/lib/python2.7/site-packages/requests/sessions.py", line 618, in send
r = adapter.send(request, **kwargs)
File "/usr/lib/python2.7/site-packages/requests/adapters.py", line 440, in send
timeout=timeout
File "/usr/lib/python2.7/site-packages/urllib3/connectionpool.py", line 601, in urlopen
chunked=chunked)
File "/usr/lib/python2.7/site-packages/urllib3/connectionpool.py", line 346, in _make_request
self._validate_conn(conn)
File "/usr/lib/python2.7/site-packages/urllib3/connectionpool.py", line 850, in _validate_conn
conn.connect()
File "/usr/lib/python2.7/site-packages/urllib3/connection.py", line 337, in connect
cert = self.sock.getpeercert()
File "/usr/lib/python2.7/site-packages/urllib3/contrib/pyopenssl.py", line 348, in getpeercert
'subjectAltName': get_subj_alt_name(x509)
File "/usr/lib/python2.7/site-packages/urllib3/contrib/pyopenssl.py", line 222, in get_subj_alt_name
for name in ext.get_values_for_type(x509.DNSName)
File "/usr/lib/python2.7/site-packages/urllib3/contrib/pyopenssl.py", line 175, in _dnsname_to_stdlib
name = idna_encode(name)
File "/usr/lib/python2.7/site-packages/urllib3/contrib/pyopenssl.py", line 173, in idna_encode
return idna.encode(name)
File "/usr/lib/python2.7/site-packages/idna/core.py", line 355, in encode
result.append(alabel(label))
File "/usr/lib/python2.7/site-packages/idna/core.py", line 265, in alabel
raise IDNAError('The label {0} is not a valid A-label'.format(label))
IDNAError: The label xn--zn8h is not a valid A-label

[zenhack]

Hey @dapetcu21,

First, this repo hasn't been maintained in some time -- these days
I maintain a fork (https://github.com/zenhack/simp_le), which is what letsencrypt.org points to and afaik most people are using.

Per rfc5892, the cat emoji is in fact illegal in domain names (along with symbols in general). Indeed, I tried putting https://🐈 .cf into my address bar, and neither firefox or chromium wants to treat it as a URL; they both try to do a search, and when I follow the link you provide it displays the domain in it's encoded form.

simp_le should probably catch the error and report it in a user-friendly way (instead of a giant stack trace).