Merge pull request #494 from mcm/mcmaster/fix_255

fix(util) Add support for obsolete HTTP date formats

falcon/request.py

@@ -622,12 +622,13 @@ class Request(object):
 
         try:
             http_date = self.get_header(header, required=required)
-            return util.http_date_to_dt(http_date)
+            return util.http_date_to_dt(http_date, obs_date=True)
         except TypeError:
             # When the header does not exist and isn't required
             return None
         except ValueError:
-            msg = ('It must be formatted according to RFC 1123.')
+            msg = ('It must be formatted according to RFC 7231, '
+                   'Section 7.1.1.1')
             raise HTTPInvalidHeader(msg, header)
 
     def get_param(self, name, required=False, store=None, default=None):

falcon/util/misc.py

@@ -101,19 +101,41 @@ def dt_to_http(dt):
     return dt.strftime('%a, %d %b %Y %H:%M:%S GMT')
 
 
-def http_date_to_dt(http_date):
+def http_date_to_dt(http_date, obs_date=False):
     """Converts an HTTP date string to a datetime instance.
 
     Args:
         http_date (str): An RFC 1123 date string, e.g.:
             "Tue, 15 Nov 1994 12:45:26 GMT".
+        obs_date (bool): Support obs-date formats according to RFC 7231, e.g.:
+            "Sunday, 06-Nov-94 08:49:37 GMT"
+            "Sun Nov  6 08:49:37 1994".
 
     Returns:
         datetime: A UTC datetime instance corresponding to the given
             HTTP date.
+
+    Raises:
+        ValueError: http_date doesn't match any of the available time formats
     """
 
-    return strptime(http_date, '%a, %d %b %Y %H:%M:%S %Z')
+    time_formats = ['%a, %d %b %Y %H:%M:%S %Z']
+
+    if obs_date:
+        time_formats.extend([
+            '%A, %d-%b-%y %H:%M:%S %Z',
+            '%a %b %d %H:%M:%S %Y',
+        ])
+
+    # Loop through the formats and return the first that matches
+    for time_format in time_formats:
+        try:
+            return strptime(http_date, time_format)
+        except ValueError:
+            continue
+
+    # Did not match any formats
+    raise ValueError('time data %r does not match known formats' % http_date)
 
 
 def to_query_str(params):

tests/test_req_vars.py

@@ -527,7 +527,7 @@ class TestReqVars(testing.TestBase):
         headers = {header: 'Thu, 04 Apr 2013'}
         expected_desc = ('The value provided for the {0} '
                          'header is invalid. It must be formatted '
-                         'according to RFC 1123.')
+                         'according to RFC 7231, Section 7.1.1.1')
 
         self._test_error_details(headers, attr,
                                  falcon.HTTPInvalidHeader,

tests/test_utils.py

@@ -79,6 +79,15 @@ class TestFalconUtils(testtools.TestCase):
             falcon.http_date_to_dt('Thu, 04 Apr 2013 10:28:54 GMT'),
             datetime(2013, 4, 4, 10, 28, 54))
 
+        self.assertEqual(
+            falcon.http_date_to_dt('Sunday, 06-Nov-94 08:49:37 GMT',
+                                   obs_date=True),
+            datetime(1994, 11, 6, 8, 49, 37))
+
+        self.assertEqual(
+            falcon.http_date_to_dt('Sun Nov  6 08:49:37 1994', obs_date=True),
+            datetime(1994, 11, 6, 8, 49, 37))
+
     def test_pack_query_params_none(self):
         self.assertEqual(
             falcon.to_query_str({}),