decorators: Only return a 403 if the user is authenticated.

This was the original intention of the replacement decorators, which would
incorrectly give 403s to users who aren't logged in. This is especially
confusing when @login_required doesn't send you to the login page.

django_cas/decorators.py

@@ -6,7 +6,9 @@ except ImportError:
     from django.utils.functional import wraps
 
 from django.contrib.auth import REDIRECT_FIELD_NAME
-from django.http import HttpResponseForbidden
+from django.contrib.auth.decorators import login_required
+from django.http import HttpResponseForbidden, HttpResponseRedirect
+from django.utils.http import urlquote
 
 __all__ = ['permission_required', 'user_passes_test']
 
@@ -16,31 +18,25 @@ def user_passes_test(test_func, login_url=None,
     returns 403 Forbidden if the user is already logged in.
     """
 
+    if not login_url:
+        from django.conf import settings
+        login_url = settings.LOGIN_URL
+
     def decorator(view_func):
         @wraps(view_func)
         def wrapper(request, *args, **kwargs):
             if test_func(request.user):
                 return view_func(request, *args, **kwargs)
-            else:
+            elif request.user.is_authenticated():
                 return HttpResponseForbidden('<h1>Permission denied</h1>')
+            else:
+                path = '%s?%s=%s' % (login_url, redirect_field_name,
+                                     urlquote(request.get_full_path()))
+                return HttpResponseRedirect(path)
         return wrapper
     return decorator
 
 
-def login_required(function=None, redirect_field_name=REDIRECT_FIELD_NAME):
-    """Replacement for django.contrib.auth.decorators.login_required that
-    returns 403 Forbidden if the user is already logged in.
-    """
-
-    actual_decorator = user_passes_test(
-        lambda u: u.is_authenticated(),
-        redirect_field_name=redirect_field_name
-    )
-    if function:
-        return actual_decorator(function)
-    return actual_decorator
-
-
 def permission_required(perm, login_url=None):
     """Replacement for django.contrib.auth.decorators.permission_required that
     returns 403 Forbidden if the user is already logged in.