[1.6.x] Fixed #20557 -- Properly decoded non-ASCII cookies on Python 3.

Thanks mitsuhiko for the report.

Non-ASCII values are supported. Non-ASCII keys still aren't, because the
current parser mangles them. That's another bug.

Simplified backport of 8aaca651 and f5add47 from master.

django/core/handlers/wsgi.py

@@ -12,6 +12,7 @@ from django.core.handlers import base
 from django.core.urlresolvers import set_script_prefix
 from django.utils import datastructures
 from django.utils.encoding import force_str, force_text, iri_to_uri
+from django.utils import six
 
 # For backwards compatibility -- lots of code uses this in the wild!
 from django.http.response import REASON_PHRASES as STATUS_CODE_TEXT
@@ -147,7 +148,10 @@ class WSGIRequest(http.HttpRequest):
 
     def _get_cookies(self):
         if not hasattr(self, '_cookies'):
-            self._cookies = http.parse_cookie(self.environ.get('HTTP_COOKIE', ''))
+            raw_cookie = self.environ.get('HTTP_COOKIE', str(''))
+            if six.PY3:
+                raw_cookie = raw_cookie.encode('iso-8859-1').decode('utf-8')
+            self._cookies = http.parse_cookie(raw_cookie)
         return self._cookies
 
     def _set_cookies(self, cookies):

tests/handlers/tests.py

@@ -1,8 +1,14 @@
-from django.core.handlers.wsgi import WSGIHandler
+# coding: utf-8
+
+from __future__ import unicode_literals
+
+from django.core.handlers.wsgi import WSGIHandler, WSGIRequest
 from django.core.signals import request_started, request_finished
 from django.db import close_old_connections, connection
 from django.test import RequestFactory, TestCase, TransactionTestCase
 from django.test.utils import override_settings
+from django.utils.encoding import force_str
+from django.utils import six
 
 
 class HandlerTests(TestCase):
@@ -30,11 +36,21 @@ class HandlerTests(TestCase):
     def test_bad_path_info(self):
         """Tests for bug #15672 ('request' referenced before assignment)"""
         environ = RequestFactory().get('/').environ
-        environ['PATH_INFO'] = '\xed'
+        environ['PATH_INFO'] = b'\xed' if six.PY2 else '\xed'
         handler = WSGIHandler()
         response = handler(environ, lambda *a, **k: None)
         self.assertEqual(response.status_code, 400)
 
+    def test_non_ascii_cookie(self):
+        """Test that non-ASCII cookies set in JavaScript are properly decoded (#20557)."""
+        environ = RequestFactory().get('/').environ
+        raw_cookie = 'want="café"'
+        if six.PY3:
+            raw_cookie = raw_cookie.encode('utf-8').decode('iso-8859-1')
+        environ['HTTP_COOKIE'] = raw_cookie
+        request = WSGIRequest(environ)
+        self.assertEqual(request.COOKIES['want'], force_str("café"))
+
 
 class TransactionsPerRequestTests(TransactionTestCase):