x509Adapter example using OpenSSL

cert_test_openssl.py

import requests

from OpenSSL.crypto import load_pkcs12
from cryptography.hazmat.primitives.serialization import load_pem_private_key, load_der_private_key 
from cryptography.hazmat.primitives.serialization import Encoding, PrivateFormat, NoEncryption
from requests_toolbelt.adapters.x509 import X509Adapter

with open('test_cert.p12', 'rb') as pkcs12_file:
	pkcs12_data = pkcs12_file.read()

pkcs12_password_bytes = "test".encode('utf8')

PyoP12 = load_pkcs12(pkcs12_data, pkcs12_password_bytes)
cert_bytes = PyoP12.get_certificate().to_cryptography().public_bytes(Encoding.DER)
pk_bytes = PyoP12.get_privatekey().to_cryptography_key().private_bytes(Encoding.DER, PrivateFormat.PKCS8, NoEncryption())

adapter = X509Adapter(max_retries=3, cert_bytes=cert_bytes, pk_bytes=pk_bytes, encoding=Encoding.DER)
session = requests.Session()
session.mount('https://', adapter)

r = session.get('https://pkiprojecttest01.dev.labs.internal/', verify=False)