Adding timeout while fetching server certs via python

Question

I am trying to fetch a list of server certificates using the Python standard SSL library to accomplish this. This is how I am doing it:

import ssl
from socket import *

urls = [i.strip().lower() for i in open("urls.txt")]
for urls in url:
    try:
        print ssl.get_server_certificate((url, 443))
    except error:
        print "No connection"
        

However for some URLs, there are connectivity issues and the connection just times out. However it waits for the default SSL timeout value (which is quite long) before timing out. How do I specify a timeout in the ssl.get_server_certificate() method? I have specified timeouts for sockets before, but I am clueless as to how to do it for this method.

Answer 1

From the docs:

SSL sockets provide the following methods of Socket Objects:

gettimeout(), settimeout(), setblocking()

So should just be as simple as:

import ssl
from socket import *

settimeout(10)

urls = [i.strip().lower() for i in open("urls.txt")]
for urls in url:
    try:
        print ssl.get_server_certificate((url, 443))
    except (error, timeout) as err:
        print "No connection: {0}".format(err)

Answer 2

This versions runs for me using with Python 3.9.12 (hat tip @bchurchill):

import ssl
import socket
socket.setdefaulttimeout(2)

urls = [i.strip().lower() for i in open("urls.txt")]
for url in urls:
    try:
        certificate = ssl.get_server_certificate((url, 443))
        print (certificate)
    except Exception as err:
        print(f"No connection to {url} due to: {err}")