This, although not pretty at all, works:

import requests

req = requests.get('https://httpbin.org')
pool = req.connection.poolmanager.connection_from_url('https://httpbin.org')
conn = pool.pool.get()
# get() removes it from the pool, so put it back in
pool.pool.put(conn)
print(conn.sock.getpeercert())

To start, abarnert’s answer is very complete

But I would like to add, that in the case you’re looking for the peer cert chain, you would need to patch yet another piece of code

import requests
sock_requests = requests.packages.urllib3.contrib.pyopenssl.WrappedSocket
def new_getpeercertchain(self,*args, **kwargs):
    x509 = self.connection.get_peer_cert_chain()
    return x509
sock_requests.getpeercertchain = new_getpeercertchain

after that you can call it in a very similiar manner as the accepted answer

HTTPResponse = requests.packages.urllib3.response.HTTPResponse
orig_HTTPResponse__init__ = HTTPResponse.__init__
def new_HTTPResponse__init__(self, *args, **kwargs):
    orig_HTTPResponse__init__(self, *args, **kwargs)
    try:
        self.peercertchain = self._connection.sock.getpeercertchain()
    except AttributeError:
        pass
HTTPResponse.__init__ = new_HTTPResponse__init__

HTTPAdapter = requests.adapters.HTTPAdapter
orig_HTTPAdapter_build_response = HTTPAdapter.build_response
def new_HTTPAdapter_build_response(self, request, resp):
    response = orig_HTTPAdapter_build_response(self, request, resp)
    try:
        response.peercertchain = resp.peercertchain
    except AttributeError:
        pass
    return response
HTTPAdapter.build_response = new_HTTPAdapter_build_response

you will get resp.peercertchain which contains a tuple of OpenSSL.crypto.X509 objects

To start, abarnert’s answer is very complete. While chasing the proposed connection-close issue of Kalkran I actually discovered that the peercert didn’t contain detailed information about the SSL Certificate.

I dug deeper in the connection and socket info and extracted the self.sock.connection.get_peer_certificate() function which contains great functions like:

• get_subject() for CN
• get_notAfter() and get_notBefore() for expiration dates
• get_serial_number() and get_signature_algorithm() for crypto related technical details
• …

Note that these are only available if you have pyopenssl installed on your system. Under the hood, urllib3 uses pyopenssl if it’s available and the standard library’s ssl module otherwise. The self.sock.connection attribute shown below only exists if self.sock is a urllib3.contrib.pyopenssl.WrappedSocket, not if it’s a ssl.SSLSocket. You can install pyopenssl with pip install pyopenssl.

Once that’s done, the code becomes:

import requests

HTTPResponse = requests.packages.urllib3.response.HTTPResponse
orig_HTTPResponse__init__ = HTTPResponse.__init__
def new_HTTPResponse__init__(self, *args, **kwargs):
    orig_HTTPResponse__init__(self, *args, **kwargs)
    try:
        self.peer_certificate = self._connection.peer_certificate
    except AttributeError:
        pass
HTTPResponse.__init__ = new_HTTPResponse__init__

HTTPAdapter = requests.adapters.HTTPAdapter
orig_HTTPAdapter_build_response = HTTPAdapter.build_response
def new_HTTPAdapter_build_response(self, request, resp):
    response = orig_HTTPAdapter_build_response(self, request, resp)
    try:
        response.peer_certificate = resp.peer_certificate
    except AttributeError:
        pass
    return response
HTTPAdapter.build_response = new_HTTPAdapter_build_response

HTTPSConnection = requests.packages.urllib3.connection.HTTPSConnection
orig_HTTPSConnection_connect = HTTPSConnection.connect
def new_HTTPSConnection_connect(self):
    orig_HTTPSConnection_connect(self)
    try:
        self.peer_certificate = self.sock.connection.get_peer_certificate()
    except AttributeError:
        pass
HTTPSConnection.connect = new_HTTPSConnection_connect

You will be able to access the result easily:

r = requests.get('https://yourdomain.tld', timeout=0.1)
print('Expires on: {}'.format(r.peer_certificate.get_notAfter()))
print(dir(r.peer_certificate))

If, like me, you want to ignore SSL Certificate warnings just add the following in the top of the file and do not SSL verify:

from requests.packages.urllib3.exceptions import InsecureRequestWarning
requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

r = requests.get('https://yourdomain.tld', timeout=0.1, verify=False)
print(dir(r.peer_certificate))

Thanks for everyone’s awesome answers.

It helped me over engineer an answer to this question:

How to add a custom CA Root certificate to the CA Store used by Python in Windows?

UPDATE 2019-02-12

Please take a look at Cert Human: SSL Certificates for Humans for an impressive rewrite of my https://github.com/neozenith/get-ca-py project by lifehackjim.

I have archived the original repository now.

Stand alone snippet

#! /usr/bin/env python
# -*- coding: utf-8 -*-
"""
Get Certificates from a request and dump them.
"""

import argparse
import sys

import requests
from requests.packages.urllib3.exceptions import InsecureRequestWarning

requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

"""
Inspired by the answers from this Stackoverflow question:
https://stackoverflow.com/questions/16903528/how-to-get-response-ssl-certificate-from-requests-in-python

What follows is a series of patching the low level libraries in requests.
"""

"""
https://stackoverflow.com/a/47931103/622276
"""

sock_requests = requests.packages.urllib3.contrib.pyopenssl.WrappedSocket


def new_getpeercertchain(self, *args, **kwargs):
    x509 = self.connection.get_peer_cert_chain()
    return x509


sock_requests.getpeercertchain = new_getpeercertchain

"""
https://stackoverflow.com/a/16904808/622276
"""

HTTPResponse = requests.packages.urllib3.response.HTTPResponse
orig_HTTPResponse__init__ = HTTPResponse.__init__


def new_HTTPResponse__init__(self, *args, **kwargs):
    orig_HTTPResponse__init__(self, *args, **kwargs)
    try:
        self.peercertchain = self._connection.sock.getpeercertchain()
    except AttributeError:
        pass


HTTPResponse.__init__ = new_HTTPResponse__init__

HTTPAdapter = requests.adapters.HTTPAdapter
orig_HTTPAdapter_build_response = HTTPAdapter.build_response


def new_HTTPAdapter_build_response(self, request, resp):
    response = orig_HTTPAdapter_build_response(self, request, resp)
    try:
        response.peercertchain = resp.peercertchain
    except AttributeError:
        pass
    return response


HTTPAdapter.build_response = new_HTTPAdapter_build_response

"""
Attempt to wrap in a somewhat usable CLI
"""


def cli(args):
    parser = argparse.ArgumentParser(description="Request any URL and dump the certificate chain")
    parser.add_argument("url", metavar="URL", type=str, nargs=1, help="Valid https URL to be handled by requests")

    verify_parser = parser.add_mutually_exclusive_group(required=False)
    verify_parser.add_argument("--verify", dest="verify", action="store_true", help="Explicitly set SSL verification")
    verify_parser.add_argument(
        "--no-verify", dest="verify", action="store_false", help="Explicitly disable SSL verification"
    )
    parser.set_defaults(verify=True)

    return vars(parser.parse_args(args))


def dump_pem(cert, outfile="ca-chain.crt"):
    """Use the CN to dump certificate to PEM format"""
    PyOpenSSL = requests.packages.urllib3.contrib.pyopenssl
    pem_data = PyOpenSSL.OpenSSL.crypto.dump_certificate(PyOpenSSL.OpenSSL.crypto.FILETYPE_PEM, cert)
    issuer = cert.get_issuer().get_components()

    print(pem_data.decode("utf-8"))

    with open(outfile, "a") as output:
        for part in issuer:
            output.write(part[0].decode("utf-8"))
            output.write("=")
            output.write(part[1].decode("utf-8"))
            output.write(",t")
        output.write("n")
        output.write(pem_data.decode("utf-8"))


if __name__ == "__main__":
    cli_args = cli(sys.argv[1:])

    url = cli_args["url"][0]
    req = requests.get(url, verify=cli_args["verify"])
    for cert in req.peercertchain:
        dump_pem(cert)

For retrieving the details of a certificate such as CN and expiry date the following script adapted from this example works well. It also avoids some errors I got which I assume were due to incorrect/incompatible versions of requests and urllib3: "AttributeError: ‘SSLSocket’ object has no attribute ‘connection’" and "AttributeError: ‘VerifiedHTTPSConnection’ object has no attribute ‘peer_certificate’"

from OpenSSL.SSL import Connection, Context, SSLv3_METHOD, TLSv1_2_METHOD
from datetime import datetime, time
import socket
host = 'www.google.com'
try:
    try:
        ssl_connection_setting = Context(SSLv3_METHOD)
    except ValueError:
        ssl_connection_setting = Context(TLSv1_2_METHOD)
    ssl_connection_setting.set_timeout(5)
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((host, 443))
        c = Connection(ssl_connection_setting, s)
        c.set_tlsext_host_name(str.encode(host))
        c.set_connect_state()
        c.do_handshake()
        cert = c.get_peer_certificate()
        print("Is Expired: ", cert.has_expired())
        print("Issuer: ", cert.get_issuer())
        subject_list = cert.get_subject().get_components()
        cert_byte_arr_decoded = {}
        for item in subject_list:
            cert_byte_arr_decoded.update({item[0].decode('utf-8'): item[1].decode('utf-8')})
        print(cert_byte_arr_decoded)
        if len(cert_byte_arr_decoded) > 0:
            print("Subject: ", cert_byte_arr_decoded)
        if cert_byte_arr_decoded["CN"]:
            print("Common Name: ", cert_byte_arr_decoded["CN"])
        end_date = datetime.strptime(str(cert.get_notAfter().decode('utf-8')), "%Y%m%d%H%M%SZ")
        print("Not After (UTC Time): ", end_date)
        diff = end_date - datetime.now()
        print('Summary: "{}" SSL certificate expires on {} i.e. {} days.'.format(host, end_date, diff.days))
        c.shutdown()
        s.close()
except:
    print("Connection to {} failed.".format(host))  

This script requires Python 3 and pyOpenSSL.

Cleaner(-ish) solution, based on previous very good answers !

1. need to patch requests.Adapter source file before overriding
   HTTPResponse class (pending pull request: https://github.com/psf/requests/pull/6039):
   • add static class variable to class HTTPAdapter(BaseAdapter) : _clsHTTPResponse = HTTPResponse
   • modify send() method to use _clsHTTPResponse rather than direct HTTPResponse object creation: resp = _clsHTTPResponse.from_httplib(…
2. use this code:

"""
Subclassing HTTP / requests to get peer_certificate back from lower levels
"""
from typing import Optional, Mapping, Any
from http.client import HTTPSConnection
from requests.adapters import HTTPAdapter, DEFAULT_POOLBLOCK
from urllib3.poolmanager import PoolManager,key_fn_by_scheme
from urllib3.connectionpool import HTTPSConnectionPool,HTTPConnectionPool
from urllib3.connection import HTTPSConnection,HTTPConnection
from urllib3.response import HTTPResponse as URLLIB3_HTTPResponse

#force urllib3 to use pyopenssl
import urllib3.contrib.pyopenssl
urllib3.contrib.pyopenssl.inject_into_urllib3()  

class HTTPSConnection_withcert(HTTPSConnection):
    def __init__(self, *args, **kw):
        self.peer_certificate = None
        super().__init__(*args, **kw)
    def connect(self):
        res = super().connect() 
        self.peer_certificate = self.sock.connection.get_peer_certificate()
        return res

class HTTPResponse_withcert(URLLIB3_HTTPResponse):
    def __init__(self, *args, **kwargs):
        self.peer_certificate = None
        res = super().__init__( *args, **kwargs)
        self.peer_certificate = self._connection.peer_certificate
        return res
       
class HTTPSConnectionPool_withcert(HTTPSConnectionPool):
    ConnectionCls   = HTTPSConnection_withcert
    ResponseCls     = HTTPResponse_withcert
    
class PoolManager_withcert(PoolManager): 
    def __init__(
        self,
        num_pools: int = 10,
        headers: Optional[Mapping[str, str]] = None,
        **connection_pool_kw: Any,
    ) -> None:   
        super().__init__(num_pools,headers,**connection_pool_kw)
        self.pool_classes_by_scheme = {"http": HTTPConnectionPool, "https": HTTPSConnectionPool_withcert}
        self.key_fn_by_scheme = key_fn_by_scheme.copy()
                
class HTTPAdapter_withcert(HTTPAdapter):
    _clsHTTPResponse = HTTPResponse_withcert
    def build_response(self, request, resp):
        response = super().build_response( request, resp)
        response.peer_certificate = resp.peer_certificate
        return response

    def init_poolmanager(self, connections, maxsize, block=DEFAULT_POOLBLOCK, **pool_kwargs):
        #do not call super() to not initialize PoolManager twice
        # save these values for pickling
        self._pool_connections  = connections
        self._pool_maxsize      = maxsize
        self._pool_block        = block

        self.poolmanager        = PoolManager_withcert(num_pools=connections, 
                                                   maxsize=maxsize,
                                                   block=block, 
                                                   strict=True, 
                                                   **pool_kwargs)
class Session_withcert(Session):
    def __init__(self):
        super().__init__()
        self.mount('https://', HTTPAdapter_withcert())

3. And thats all !
   You can now use your new session Session_withcert() like the base one, but you can also do :

ss= Session_withcert()
resp=ss.get("https://www.google.fr")
resp.peer_certificate.get_subject()
print(resp.peer_certificate.get_subject())

which will output:

<X509Name object '/CN=*.google.fr'>

Just do this:

import requests

with requests.get("https://www.bilibili.com", stream=True) as response:
    certificate_info = response.raw.connection.sock.getpeercert()
    subject = dict(x[0] for x in certificate_info['subject'])
    issuer = dict(x[0] for x in certificate_info['issuer'])

    print("commonName:", subject['commonName'])
    print("issuer:", issuer['commonName'])

Then the output is :

commonName: *.bilibili.com
issuer: GlobalSign RSA OV SSL CA 2018

Wish to help you.