diff --git a/src/postorius/auth/decorators.py b/src/postorius/auth/decorators.py
index e6fa531..3dd51e5 100644
--- a/src/postorius/auth/decorators.py
+++ b/src/postorius/auth/decorators.py
@@ -23,7 +23,8 @@
 
 from postorius.models import (Domain, List, Member, MailmanUser,
                               MailmanApiError, Mailman404Error)
-from postorius.utils import user_is_in_list_roster
+
+from .utils import set_user_access_props
 
 
 def basic_auth_login(fn):
@@ -57,9 +58,7 @@
             raise PermissionDenied
         if user.is_superuser:
             return fn(*args, **kwargs)
-        if not hasattr(user, 'is_list_owner'):
-            mlist = List.objects.get_or_404(fqdn_listname=list_id)
-            user.is_list_owner = user_is_in_list_roster(user, mlist, "owners")
+        set_user_access_props(user, list_id)
         if user.is_list_owner:
             return fn(*args, **kwargs)
         else:
@@ -79,15 +78,7 @@
             raise PermissionDenied
         if user.is_superuser:
             return fn(*args, **kwargs)
-        if (not hasattr(user, 'is_list_owner')
-            or not hasattr(user, 'is_list_moderator')):
-            mlist = List.objects.get_or_404(fqdn_listname=list_id)
-            if not hasattr(user, 'is_list_owner'):
-                user.is_list_owner = user_is_in_list_roster(
-                    user, mlist, "owners")
-            if not hasattr(user, 'is_list_moderator'):
-                user.is_list_moderator = user_is_in_list_roster(
-                    user, mlist, "moderators")
+        set_user_access_props(user, list_id)
         if user.is_list_owner or user.is_list_moderator:
             return fn(*args, **kwargs)
         else:
diff --git a/src/postorius/auth/utils.py b/src/postorius/auth/utils.py
new file mode 100644
index 0000000..fc23c18
--- /dev/null
+++ b/src/postorius/auth/utils.py
@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 1998-2015 by the Free Software Foundation, Inc.
+#
+# This file is part of Postorius.
+#
+# Postorius is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option)
+# any later version.
+#
+# Postorius is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# Postorius.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Authentication and authorization-related utilities.
+"""
+
+def user_is_in_list_roster(user, mailing_list, roster):
+    if not user.is_authenticated():
+        return False
+    if not hasattr(user, 'other_emails'):
+        set_other_emails(user)
+    addresses = set([user.email]) | set(user.other_emails)
+    if addresses & set(getattr(mailing_list, roster)):
+        return True # At least one address is in the roster
+    return False
+
+
+def set_user_access_props(user, mlist):
+    if not isinstance(mlist, List):
+        mlist = List.objects.get_or_404(mlist)
+    if not hasattr(user, 'is_list_owner'):
+        user.is_list_owner = user_is_in_list_roster(
+            user, mlist, "owners")
+    if not hasattr(user, 'is_list_moderator'):
+        user.is_list_moderator = user_is_in_list_roster(
+            user, mlist, "moderators")
diff --git a/src/postorius/utils.py b/src/postorius/utils.py
index 63a2564..00f7c00 100644
--- a/src/postorius/utils.py
+++ b/src/postorius/utils.py
@@ -115,13 +115,3 @@
         return
     if user.email in user.other_emails:
         user.other_emails.remove(user.email)
-
-def user_is_in_list_roster(user, mailing_list, roster):
-    if not user.is_authenticated():
-        return False
-    if not hasattr(user, 'other_emails'):
-        set_other_emails(user)
-    addresses = set([user.email]) | set(user.other_emails)
-    if addresses & set(getattr(mailing_list, roster)):
-        return True # At least one address is in the roster
-    return False
diff --git a/src/postorius/views/generic.py b/src/postorius/views/generic.py
index e12e846..3b18d66 100644
--- a/src/postorius/views/generic.py
+++ b/src/postorius/views/generic.py
@@ -22,6 +22,7 @@
 
 from postorius.models import List, MailmanUser, MailmanApiError, Mailman404Error
 from postorius import utils
+from postorius.auth.utils import set_user_access_props
 
 
 class MailmanClientMixin(object):
@@ -48,16 +49,10 @@
     def dispatch(self, request, *args, **kwargs):
         # get the list object.
         if 'list_id' in kwargs:
-            try:
-                self.mailing_list = self._get_list(kwargs['list_id'],
-                                                   int(kwargs.get('page', 1)))
-            except MailmanApiError:
-                return utils.render_api_error(request)
+            self.mailing_list = self._get_list(kwargs['list_id'],
+                                               int(kwargs.get('page', 1)))
             utils.set_other_emails(request.user)
-            request.user.is_list_owner = utils.user_is_in_list_roster(
-                request.user, self.mailing_list, "owners")
-            request.user.is_list_moderator = utils.user_is_in_list_roster(
-                request.user, self.mailing_list, "moderators")
+            set_user_access_props(request.user)
         # set the template
         if 'template' in kwargs:
             self.template = kwargs['template']