Verifying HTTPS certificates with urllib.request

Elias Zamarias answer still works, but gives a deprecation warning:

DeprecationWarning: cafile, cpath and cadefault are deprecated, use a custom context instead.

I was able to solve the same problem this way instead (using Python 3.7.0):

import ssl
import urllib.request

ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
response = urllib.request.urlopen("http://www.example.com", context=ssl_context)

You can download the certificates Mozilla in a format usable for urllib (e.g. PEM format) at http://curl.haxx.se/docs/caextract.html

Works in python 2.7 and above

context = ssl.create_default_context(cafile=certifi.where())
req = urllib2.urlopen(urllib2.Request(url, body, headers), context=context)

I found a library that does what I'm trying to do: Certifi. It can be installed by running pip install certifi from the command line.

Making requests and verifying them is now easy:

import certifi
import urllib.request

urllib.request.urlopen("https://example.com/", cafile=certifi.where())

As I expected, this returns a HTTPResponse object for a site with a valid certificate and raises a ssl.CertificateError exception for a site with an invalid certificate.