Note: This solution is a complete hack. And works only for requests < 2.28 (https://github.com/psf/requests/pull/6074)
Short answer: Set the CURL_CA_BUNDLE environment variable to an empty string.
Before:
$ python
import requests
requests.get('http://www.google.com')
<Response [200]>
requests.get('https://www.google.com')
...
File "/usr/local/lib/python2.7/site-packages/requests-2.17.3-py2.7.egg/requests/adapters.py", line 514, in send
raise SSLError(e, request=request)
requests.exceptions.SSLError: ("bad handshake: Error([('SSL routines', 'SSL3_GET_SERVER_CERTIFICATE', 'certificate verify failed')],)",)
After:
$ CURL_CA_BUNDLE="" python
import requests
requests.get('http://www.google.com')
<Response [200]>
requests.get('https://www.google.com')
/usr/local/lib/python2.7/site-packages/urllib3-1.21.1-py2.7.egg/urllib3/connectionpool.py:852: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings InsecureRequestWarning)
<Response [200]>
How it works
This solution works because Python requests overwrites the default value for verify from the environment variables CURL_CA_BUNDLE and REQUESTS_CA_BUNDLE, as can be seen here:
if verify is True or verify is None:
verify = (os.environ.get('REQUESTS_CA_BUNDLE') or
os.environ.get('CURL_CA_BUNDLE'))
The environment variables are meant to specify the path to the certificate file or CA_BUNDLE and are copied into verify. However, by setting CURL_CA_BUNDLE to an empty string, the empty string is copied into verify and in Python, an empty string evaluates to False.
Note that this hack only works with the CURL_CA_BUNDLE environment variable - it does not work with the REQUESTS_CA_BUNDLE. This is because verify is set with the following statement:
verify = (os.environ.get('REQUESTS_CA_BUNDLE') or os.environ.get('CURL_CA_BUNDLE'))
It only works with CURL_CA_BUNDLE because '' or None is not the same as None or '', as can be seen below:
print repr(None or "")
# Prints: ''
print repr("" or None )
# Prints: None
