Replace deprecated datetime.utcnow() by datetime.now(timezone.utc)

The `utcnow` function has been deprecated starting from Python 3.12:
https://docs.python.org/3/library/datetime.html#datetime.datetime.utcnow

Thus replace `datetime.datetime.utcnow()` by
`datetime.datetime.now(datetime.timezone.utc)`. Also replace `pytz` with
standard Python.

Fixes: IdentityPython#934

Author: bdrung

pyproject.toml

@@ -44,7 +44,6 @@ importlib-resources = {python = "<3.9", version = "*"}
 paste = {optional = true, version = "*"}
 pyopenssl = "<24.3.0"
 python-dateutil = "*"
-pytz = "*"
 "repoze.who" = {optional = true, version = "*"}
 requests = "^2"
 xmlschema = "^2"
@@ -68,7 +67,6 @@ ipdb = "^0.13.9"
 mypy = "^1.0.0"
 types-pyopenssl = "^23.0.0.3"
 types-python-dateutil = "^2.8.19.6"
-types-pytz = "^2022.7.1.0"
 types-setuptools = "^67.2.0.1"
 types-six = "^1.16.21.4"
 types-requests = "^2.28.11.12"

src/saml2/cert.py

@@ -7,7 +7,6 @@
 
 from OpenSSL import crypto
 import dateutil.parser
-import pytz
 
 import saml2.cryptography.pki
 
@@ -278,7 +277,7 @@ def verify_chain(self, cert_chain_str_list, cert_str):
 
     def certificate_not_valid_yet(self, cert):
         starts_to_be_valid = dateutil.parser.parse(cert.get_notBefore())
-        now = pytz.UTC.localize(datetime.datetime.utcnow())
+        now = datetime.datetime.now(datetime.timezone.utc)
         if starts_to_be_valid < now:
             return False
         return True

src/saml2/mongo_store.py

@@ -205,7 +205,7 @@ def store(self, value, **kwargs):
         doc.update(kwargs)
         # Add timestamp to all documents to allow external garbage collecting
         if "created_at" not in doc:
-            doc["created_at"] = datetime.datetime.utcnow()
+            doc["created_at"] = datetime.datetime.now(datetime.timezone.utc)
         _ = self.db.insert_one(doc)
 
     def get(self, value=None, **kwargs):

src/saml2/sigver.py

@@ -29,7 +29,6 @@
 from urllib import parse
 
 from OpenSSL import crypto
-import pytz
 
 from saml2 import ExtensionElement
 from saml2 import SamlBase
@@ -387,7 +386,7 @@ def active_cert(key):
     except AttributeError:
         return False
 
-    now = pytz.UTC.localize(datetime.datetime.utcnow())
+    now = datetime.datetime.now(datetime.timezone.utc)
     valid_from = dateutil.parser.parse(cert.get_notBefore())
     valid_to = dateutil.parser.parse(cert.get_notAfter())
     active = not cert.has_expired() and valid_from <= now < valid_to

src/saml2/time_util.py

@@ -6,7 +6,7 @@
 """
 
 import calendar
-from datetime import datetime
+from datetime import datetime, timezone
 from datetime import timedelta
 import re
 import sys
@@ -175,7 +175,7 @@ def time_in_a_while(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0
     :return: UTC time
     """
     delta = timedelta(days, seconds, microseconds, milliseconds, minutes, hours, weeks)
-    return datetime.utcnow() + delta
+    return datetime.now(timezone.utc) + delta
 
 
 def time_a_while_ago(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0):
@@ -185,7 +185,7 @@ def time_a_while_ago(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=
                     minutes[, hours[, weeks]]]]]]])
     """
     delta = timedelta(days, seconds, microseconds, milliseconds, minutes, hours, weeks)
-    return datetime.utcnow() - delta
+    return datetime.now(timezone.utc) - delta
 
 
 def in_a_while(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0, format=TIME_FORMAT):

tests/test_41_response.py

@@ -127,7 +127,7 @@ def test_issuer_none(self):
     @patch("saml2.time_util.datetime")
     def test_false_sign(self, mock_datetime, caplog):
         caplog.set_level(logging.ERROR)
-        mock_datetime.utcnow = Mock(return_value=datetime.datetime(2016, 9, 4, 9, 59, 39))
+        mock_datetime.now = Mock(return_value=datetime.datetime(2016, 9, 4, 9, 59, 39, tzinfo=datetime.timezone.utc))
         with open(FALSE_ASSERT_SIGNED) as fp:
             xml_response = fp.read()
 

tests/test_44_authnresp.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 from contextlib import closing
-from datetime import datetime
+from datetime import datetime, timezone
 
 from dateutil import parser
 from pathutils import dotname
@@ -131,7 +131,7 @@ def test_verify_w_authn(self):
         assert len(authn_info) == 1
         assert authn_info[0][0] == INTERNETPROTOCOLPASSWORD
         assert authn_info[0][1] == ["http://www.example.com/login"]
-        now = datetime.utcnow()
+        now = datetime.now(timezone.utc)
         dt = parser.parse(authn_info[0][2])
         assert now.year == dt.year and now.month == dt.month and now.day == dt.day
         session_info = self.ar.session_info()