python - ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)

Question

I am trying to use the betbrain.py from Github (https://github.com/gto76/betbrain-scraper) that has the following code:

#!/usr/bin/python3
#
# Usage: betbrain.py [URL or FILE] [OUTPUT-FILE]
# Scrapes odds from passed betbrain page and writes them to
# stdout, or file if specified.

import os
import sys
import urllib.request


from bs4 import BeautifulSoup
from http.cookiejar import CookieJar

import parser_betbrain
import printer

DEFAULT_URL = 'https://www.betbrain.com/football/england/premier-league/#!/matches/'


# If no arguments are present, it parses the default page.
# Argument can be an URL or a local file.
def main():
  html = getHtml(sys.argv)
  soup = BeautifulSoup(html, "html.parser")
  matches = parser_betbrain.getMatches(soup)
  string = printer.matchesToString(matches)
  output(string, sys.argv)

def getHtml(argv):
  if len(argv) <= 1:
    return scrape(DEFAULT_URL)
  elif argv[1].startswith("http"):
    return scrape(argv[1])
  else:
    return readFile(argv[1])

# Returns html file located at URL.
def scrape(url):
  cj = CookieJar()
  opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
  try:
    return opener.open(url)
  except ValueError:
    error("Invalid URL: " + url)

def readFile(path):
  try:
    return open(path, encoding='utf8')
  except IOError:
    error("Invalid input filename: " + path)

def output(string, argv):
  if len(argv) <= 2:
    print(string)
  else:
    writeFile(argv[2], string)

def writeFile(path, string):
  try:  
    fo = open(path, "w", encoding='utf8')
    fo.write(string);
    fo.close()
  except IOError:
    error("Invalid output filename: " + path)

def error(msg):
  msg = os.path.basename(__file__)+": "+msg
  print(msg, file=sys.stderr)
  sys.exit(1)

if __name__ == '__main__':
  main()

However when run it comes back with this error

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1318, in do_open
    encode_chunked=req.has_header('Transfer-encoding'))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1239, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1285, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1234, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1026, in _send_output
    self.send(msg)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 964, in send
    self.connect()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1400, in connect
    server_hostname=server_hostname)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 401, in wrap_socket
    _context=self, _session=session)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 808, in __init__
    self.do_handshake()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 1061, in do_handshake
    self._sslobj.do_handshake()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 683, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/Daniel/Desktop/betbrain-scraper-master 2/betbrain.py", line 71, in <module>
    main()
  File "/Users/Daniel/Desktop/betbrain-scraper-master 2/betbrain.py", line 22, in main
    html = getHtml(sys.argv)
  File "/Users/Daniel/Desktop/betbrain-scraper-master 2/betbrain.py", line 30, in getHtml
    return scrape(DEFAULT_URL)
  File "/Users/Daniel/Desktop/betbrain-scraper-master 2/betbrain.py", line 41, in scrape
    return opener.open(url)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 526, in open
    response = self._open(req, data)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 544, in _open
    '_open', req)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1361, in https_open
    context=self._context, check_hostname=self._check_hostname)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1320, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)>

How can I fix this problem? I am running Python 3.6.0 on MacOS 10.12.1

Answer 1

Open a terminal and take a look at:

/Applications/Python 3.6/Install Certificates.command

Python 3.6 on MacOS uses an embedded version of OpenSSL, which does not use the system certificate store. More details here.

(To be explicit: MacOS users can probably resolve by opening Finder and double clicking Install Certificates.command)