Thanks to Chris A and Roger C for their information. Very helpful and I am
working on both of their suggestions. But now I've run into a new related
problem.
I still am trying to get stock information using Standard Library calls for now
(although I understand that the requests module makes this kind of thing very
easy).
My general approach (Python 3) is to build up a URL by concatenating an
parameters, and make a call to url.request.urlopen. I then do a 'read' on what
was returned. For example, in my class, I use the following code to get weather
data from weatherman.org:
URL = 'http://api.openweathermap.org/data/2.5/weather?q=' + city +
'&mode=xml'+ '&APPID=' + API_KEY
response = urllib.request.urlopen(URL)
responseString = str(response.read())
I then have some code to parse out the pieces of the returned information.
This works great and an excellent example of the power of using API's with
Python.
In looking for a stock data API, Chris suggested alpha vantage.co (and Roger
made a nice suggestion as to how to parse it). But when I use their API, I get
an error:
ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed
(_ssl.c:749)
I have tried a number of different API's and found that if the URL starts with
'https', it always fails. Even a simple example that I found here:
https://pythonspot.com/urllib-tutorial-python-3/
<https://pythonspot.com/urllib-tutorial-python-3/> fails the same way.
Here's what I see when I try that example:
>>> import urllib.request
>>> html = urllib.request.urlopen('https://arstechnica.com').read()
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 "<pyshell#6>", line 1, in <module>
html = urllib.request.urlopen('https://arstechnica.com').read()
File
"/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py",
line 223, in urlopen
return opener.open(url, data, timeout)
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)>
>>>
All my tests return the same tracebacks.
Am I doing something wrong? Is there another way (besides using the requests
module which DOES work for me) to get data from an https URL?
Any help would be appreciated.
Thanks,
Irv
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