Certificate error from urllib

[micromouseonline]

When I do the install as directed and then run mmsim, I get an error. Specifically, this error:

  urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)>

The reason is that the Python installer on MacOs may not have run the certificate commands.

This question on StackExchange has the answer:

https://stackoverflow.com/questions/44649449/brew-installation-of-python-3-6-1-ssl-certificate-verify-failed-certificate/44649450#44649450

[micromouseonline]

Just to be clear, this is not an issue with the mmsim code. The problem is with the way that Python may be installed under MacOS. I used the pkg installation from python.org.

The issue can be demonstrated from the Python shell:

  Python 3.7.2 (v3.7.2:9a3ffc0492, Dec 24 2018, 02:44:43) 
  [Clang 6.0 (clang-600.0.57)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  >>> from urllib.request import urlretrieve
  >>> url = 'https://github.com/micromouseonline/mazefiles/'\
  ...         'archive/master.tar.gz'
  >>> url
  'https://github.com/micromouseonline/mazefiles/archive/master.tar.gz'
  >>> reveal_tar, headers = urlretrieve(url)
  Traceback (most recent call last):
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1317, in do_open
    encode_chunked=req.has_header('Transfer-encoding'))
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1229, in request
    self._send_request(method, url, body, headers, encode_chunked)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1275, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1224, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1016, in _send_output
    self.send(msg)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 956, in send
    self.connect()
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1392, in connect
    server_hostname=server_hostname)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 412, in wrap_socket
    session=session
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 853, in _create
    self.do_handshake()
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 1117, in do_handshake
    self._sslobj.do_handshake()
  ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)

  During handling of the above exception, another exception occurred:

  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 247, in urlretrieve
    with contextlib.closing(urlopen(url, data)) as fp:
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 525, in open
    response = self._open(req, data)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 543, in _open
    '_open', req)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 503, in _call_chain
    result = func(*args)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1360, in https_open
    context=self._context, check_hostname=self._check_hostname)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1319, in do_open
    raise URLError(err)
  urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)>
  >>> exit()

[Peque]

Oh, I understand. I cannot fix that. 😅

However, if you confirm that you could use requests to get content from an HTTPS source (i.e.: a GitHub page) without having those issues, I would not mind adding that extra dependency. Apparently they use certifi package, which may not require you to have any special system-wide configuration.

[micromouseonline]

I have already made the fix now. so it is not clear that any success I might have would not be due to the fix rather than the change. It is purely a local configuration matter. I put it up as an issue so that others might find a solution if they run into a similar problem. Perhaps a note in the README might be appropriate? — Peter Harrison peter.harrison@helicron.net

…

On 8 Mar 2019, at 16:47, Miguel Sánchez de León Peque ***@***.***> wrote: Oh, I understand. I cannot fix that. 😅 However, if you confirm that you could use requests to get content from an HTTPS source (i.e.: a GitHub page) without having those issues, I would not mind adding that extra dependency. Apparently they use certifi package, which may not require you to have any special system-wide configuration. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[Peque]

@micromouseonline I will leave this open, as I think a note in the README file could be appropriate, as you suggested.

Do not know whether I will add it soon or not, but definitely some day! 😄

Pull requests accepted too. 😜

[micromouseonline]

Ok. It was not my issue to close really. I was just rushing through some tidying up on Github :) — Peter Harrison peter.harrison@helicron.net

…

On 1 Jul 2019, at 20:16, Miguel Sánchez de León Peque ***@***.***> wrote: @micromouseonline I will leave this open, as I think a note in the README file could be appropriate, as you suggested. Do not know whether I will add it soon or not, but definitely some day! 😄 Pull requests accepted too. 😜 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.