Introduce and use locale-naive rfc2822 date format function (#44868)

* Introduce and use locale-naive rfc2822 date format function. Fixes #44857

* Adjust test expected response

changelogs/fragments/urls-if-modified-since.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+- get_url / uri - Use custom rfc2822 date format function instead of locale specific strftime (https://github.com/ansible/ansible/issues/44857)

lib/ansible/module_utils/urls.py

@@ -822,6 +822,23 @@ def maybe_add_ssl_handler(url, validate_certs):
         return SSLValidationHandler(hostname, port)
 
 
+def rfc2822_date_string(timetuple, zone='-0000'):
+    """Accepts a timetuple and optional zone which defaults to ``-0000``
+    and returns a date string as specified by RFC 2822, e.g.:
+
+    Fri, 09 Nov 2001 01:08:47 -0000
+
+    Copied from email.utils.formatdate and modified for separate use
+    """
+    return '%s, %02d %s %04d %02d:%02d:%02d %s' % (
+        ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][timetuple[6]],
+        timetuple[2],
+        ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
+         'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'][timetuple[1] - 1],
+        timetuple[0], timetuple[3], timetuple[4], timetuple[5],
+        zone)
+
+
 class Request:
     def __init__(self, headers=None, use_proxy=True, force=False, timeout=10, validate_certs=True,
                  url_username=None, url_password=None, http_agent=None, force_basic_auth=False,
@@ -1037,7 +1054,7 @@ class Request:
             request.add_header('cache-control', 'no-cache')
         # or we do it if the original is more recent than our copy
         elif last_mod_time:
-            tstamp = last_mod_time.strftime('%a, %d %b %Y %H:%M:%S +0000')
+            tstamp = rfc2822_date_string(last_mod_time.timetuple())
             request.add_header('If-Modified-Since', tstamp)
 
         # user defined headers now, which may override things we've set above

lib/ansible/modules/net_tools/basics/uri.py

@@ -405,6 +405,7 @@ def uri(module, url, dest, body, body_format, method, headers, socket_timeout):
     else:
         data = body
 
+    kwargs = {}
     if dest is not None:
         # Stash follow_redirects, in this block we don't want to follow
         # we'll reset back to the supplied value soon
@@ -424,15 +425,13 @@ def uri(module, url, dest, body, body_format, method, headers, socket_timeout):
             dest = os.path.join(dest, url_filename(url))
         # if destination file already exist, only download if file newer
         if os.path.exists(dest):
-            t = datetime.datetime.utcfromtimestamp(os.path.getmtime(dest))
-            tstamp = t.strftime('%a, %d %b %Y %H:%M:%S +0000')
-            headers['If-Modified-Since'] = tstamp
+            kwargs['last_mod_time'] = datetime.datetime.utcfromtimestamp(os.path.getmtime(dest))
 
         # Reset follow_redirects back to the stashed value
         module.params['follow_redirects'] = follow_redirects
 
     resp, info = fetch_url(module, url, data=data, headers=headers,
-                           method=method, timeout=socket_timeout)
+                           method=method, timeout=socket_timeout, **kwargs)
 
     try:
         content = resp.read()

test/units/module_utils/urls/test_Request.py

@@ -362,7 +362,7 @@ def test_Request_open_last_mod(urlopen_mock, install_opener_mock):
     args = urlopen_mock.call_args[0]
     req = args[0]
 
-    assert req.headers.get('If-modified-since') == now.strftime('%a, %d %b %Y %H:%M:%S +0000')
+    assert req.headers.get('If-modified-since') == now.strftime('%a, %d %b %Y %H:%M:%S -0000')
 
 
 def test_Request_open_headers_not_dict(urlopen_mock, install_opener_mock):