diff --git a/combo/apps/lingo/views.py b/combo/apps/lingo/views.py
index 13442208..fba3bd5a 100644
--- a/combo/apps/lingo/views.py
+++ b/combo/apps/lingo/views.py
@@ -40,11 +40,7 @@ import eopayment
 
 from combo.data.models import Page
 from combo.utils import check_request_signature, aes_hex_decrypt, DecryptionError
-
-if 'mellon' in settings.INSTALLED_APPS:
-    from mellon.models import UserSAMLIdentifier
-else:
-    UserSAMLIdentifier = None
+from combo.profile.utils import get_user_from_name_id
 
 from .models import (Regie, BasketItem, Transaction, TransactionOperation,
         LingoBasketCell, SelfDeclaredInvoicePayment)
@@ -125,12 +121,9 @@ class AddBasketItemApiView(View):
 
         try:
             if request.GET.get('NameId'):
-                if UserSAMLIdentifier is None:
-                    raise Exception('missing mellon?')
-                try:
-                    user = UserSAMLIdentifier.objects.get(name_id=request.GET.get('NameId')).user
-                except UserSAMLIdentifier.DoesNotExist:
-                    raise Exception('unknown name id')
+                user = get_user_from_name_id(request.GET.get('NameId'))
+                if user is None:
+                    raise User.DoesNotExist()
             elif request.GET.get('email'):
                 user = User.objects.get(email=request.GET.get('email'))
             else:
@@ -198,12 +191,9 @@ class RemoveBasketItemApiView(View):
 
         try:
             if request.GET.get('NameId'):
-                if UserSAMLIdentifier is None:
-                    raise Exception('missing mellon?')
-                try:
-                    user = UserSAMLIdentifier.objects.get(name_id=request.GET.get('NameId')).user
-                except UserSAMLIdentifier.DoesNotExist:
-                    raise Exception('unknown name id')
+                user = get_user_from_name_id(request.GET.get('NameId'))
+                if user is None:
+                    raise User.DoesNotExist()
             elif request.GET.get('email'):
                 user = User.objects.get(email=request.GET.get('email'))
             else:
diff --git a/combo/apps/newsletters/forms.py b/combo/apps/newsletters/forms.py
index 4c1ebfb3..b5b98cac 100644
--- a/combo/apps/newsletters/forms.py
+++ b/combo/apps/newsletters/forms.py
@@ -38,8 +38,9 @@ class NewslettersManageForm(forms.Form):
             logger.error('Error occured while getting newsletters: %r', e)
             return
         self.params = {}
-        if hasattr(self.user, 'saml_identifiers') and self.user.saml_identifiers.exists():
-            self.params['uuid'] = self.user.saml_identifiers.first().name_id
+        user_name_id = self.user.get_name_id()
+        if user_name_id:
+            self.params['uuid'] = user_name_id
 
         # get mobile number from mellon session as it is not user attribute
         if self.request.session.get('mellon_session'):
diff --git a/combo/apps/wcs/models.py b/combo/apps/wcs/models.py
index 9f45da62..252e0167 100644
--- a/combo/apps/wcs/models.py
+++ b/combo/apps/wcs/models.py
@@ -313,8 +313,10 @@ class WcsCurrentFormsCell(WcsUserDataBaseCell):
 
     def get_api_url(self, context):
         user = self.get_concerned_user(context)
-        if hasattr(user, 'saml_identifiers') and user.saml_identifiers.exists():
-            return '/api/users/%s/forms' % user.saml_identifiers.first().name_id
+        if user:
+            user_name_id = user.get_name_id()
+            if user_name_id:
+                return '/api/users/%s/forms' % user_name_id
         return '/api/user/forms'
 
     @property
@@ -386,8 +388,10 @@ class WcsCurrentDraftsCell(WcsUserDataBaseCell):
 
     def get_api_url(self, context):
         user = self.get_concerned_user(context)
-        if hasattr(user, 'saml_identifiers') and user.saml_identifiers.exists():
-            return '/api/users/%s/drafts' % user.saml_identifiers.first().name_id
+        if user:
+            user_name_id = user.get_name_id()
+            if user_name_id:
+                return '/api/users/%s/drafts' % user_name_id
         return '/api/user/drafts'
 
     def get_cell_extra_context(self, context):
diff --git a/combo/profile/__init__.py b/combo/profile/__init__.py
index c5fb5908..e34e80f2 100644
--- a/combo/profile/__init__.py
+++ b/combo/profile/__init__.py
@@ -21,6 +21,13 @@ import django.apps
 from django.utils.translation import ugettext_lazy as _
 
 
+def user_get_name_id(user):
+    saml_identifier = user.saml_identifiers.first()
+    if saml_identifier:
+        return saml_identifier.name_id
+    return None
+
+
 class AppConfig(django.apps.AppConfig):
     name = 'combo.profile'
     verbose_name = _('Profile')
@@ -28,6 +35,8 @@ class AppConfig(django.apps.AppConfig):
     def ready(self):
         from combo.apps.search import engines
         engines.register(self.get_search_engines)
+        from django.contrib.auth import get_user_model
+        get_user_model().add_to_class('get_name_id', user_get_name_id)
 
     def get_search_engines(self):
         from combo.data.models import Page
diff --git a/combo/profile/utils.py b/combo/profile/utils.py
new file mode 100644
index 00000000..e8ca8fe0
--- /dev/null
+++ b/combo/profile/utils.py
@@ -0,0 +1,32 @@
+# combo - content management system
+# Copyright (C) 2014-2019  Entr'ouvert
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from django.conf import settings
+
+
+if 'mellon' in settings.INSTALLED_APPS:
+    from mellon.models import UserSAMLIdentifier
+else:
+    UserSAMLIdentifier = None
+
+
+def get_user_from_name_id(name_id):
+    if not UserSAMLIdentifier:
+        return None
+    try:
+        return UserSAMLIdentifier.objects.get(name_id=name_id).user
+    except UserSAMLIdentifier.DoesNotExist:
+        return None
diff --git a/combo/public/templatetags/combo.py b/combo/public/templatetags/combo.py
index 8791de6b..47e498f6 100644
--- a/combo/public/templatetags/combo.py
+++ b/combo/public/templatetags/combo.py
@@ -34,9 +34,6 @@ from combo.public.menu import get_menu_context
 from combo.utils import NothingInCacheException, flatten_context
 from combo.apps.dashboard.models import DashboardCell, Tile
 
-if 'mellon' in settings.INSTALLED_APPS:
-    from mellon.models import UserSAMLIdentifier
-
 register = template.Library()
 
 def skeleton_text(context, placeholder_name, content=''):
@@ -248,9 +245,10 @@ def signed(obj):
 
 @register.filter
 def name_id(user):
-    saml_id = UserSAMLIdentifier.objects.filter(user=user).last()
-    if saml_id:
-        return saml_id.name_id
+    if user:
+        user_name_id = user.get_name_id()
+        if user_name_id:
+            return user_name_id
     # it is important to raise this so get_templated_url is aborted and no call
     # is tried with a missing user argument.
     raise VariableDoesNotExist('name_id')
diff --git a/combo/public/views.py b/combo/public/views.py
index 60fb0829..04091e46 100644
--- a/combo/public/views.py
+++ b/combo/public/views.py
@@ -45,14 +45,13 @@ from haystack.query import SearchQuerySet, SQ
 
 if 'mellon' in settings.INSTALLED_APPS:
     from mellon.utils import get_idps
-    from mellon.models import UserSAMLIdentifier
 else:
     get_idps = lambda: []
-    UserSAMLIdentifier = None
 
 from combo.data.models import (CellBase, PostException, Page, Redirect,
         ParentContentCell, TextCell, PageSnapshot)
 from combo.profile.models import Profile
+from combo.profile.utils import get_user_from_name_id
 from combo.apps.search.models import SearchCell
 from combo import utils
 
@@ -81,11 +80,8 @@ def modify_global_context(request, ctx):
             ctx['selected_user'] = User.objects.get(id=ctx['user_id'])
         except (User.DoesNotExist, ValueError):
             pass
-    if 'name_id' in ctx and UserSAMLIdentifier:
-        try:
-            ctx['selected_user'] = UserSAMLIdentifier.objects.get(name_id=ctx['name_id']).user
-        except UserSAMLIdentifier.DoesNotExist:
-            pass
+    if 'name_id' in ctx:
+        ctx['selected_user'] = get_user_from_name_id(ctx['name_id'])
 
 @csrf_exempt
 def ajax_page_cell(request, page_pk, cell_reference):
diff --git a/combo/utils/requests_wrapper.py b/combo/utils/requests_wrapper.py
index 6dbde7d4..66425309 100644
--- a/combo/utils/requests_wrapper.py
+++ b/combo/utils/requests_wrapper.py
@@ -79,12 +79,13 @@ class Requests(RequestsSession):
             else:
                 query_params = {}
                 if federation_key == 'nameid':
-                    query_params['NameID'] = user.saml_identifiers.first().name_id
+                    query_params['NameID'] = user.get_name_id()
                 elif federation_key == 'email':
                     query_params['email'] = user.email
                 else: # 'auto'
-                    if hasattr(user, 'saml_identifiers') and user.saml_identifiers.exists():
-                        query_params['NameID'] = user.saml_identifiers.first().name_id
+                    user_name_id = user.get_name_id()
+                    if user_name_id:
+                        query_params['NameID'] = user_name_id
                     else:
                         query_params['email'] = user.email
 
diff --git a/combo/utils/urls.py b/combo/utils/urls.py
index 24be39f6..57e67be7 100644
--- a/combo/utils/urls.py
+++ b/combo/utils/urls.py
@@ -42,8 +42,9 @@ def get_templated_url(url, context=None):
         user = getattr(context.get('request'), 'user', None)
         if user and user.is_authenticated():
             template_vars['user_email'] = quote(user.email)
-            if hasattr(user, 'saml_identifiers') and user.saml_identifiers.exists():
-                template_vars['user_nameid'] = quote(user.saml_identifiers.first().name_id)
+            user_nameid = user.get_name_id()
+            if user_nameid:
+                template_vars['user_nameid'] = quote(user_nameid)
     template_vars.update(settings.TEMPLATE_VARS)
     if '{{' in url or '{%' in url:  # Django template
         try:
diff --git a/tests/test_lingo_remote_regie.py b/tests/test_lingo_remote_regie.py
index 67b8480b..6ae70878 100644
--- a/tests/test_lingo_remote_regie.py
+++ b/tests/test_lingo_remote_regie.py
@@ -75,15 +75,9 @@ class MockUser(object):
     def is_authenticated(self):
         return True
 
-    def __init__(self):
-        class MockSAMLUsers(object):
-            def exists(self):
-                return True
-            def first(self):
-                class MockSAMLUser(object):
-                    name_id = 'r2d2'
-                return MockSAMLUser()
-        self.saml_identifiers = MockSAMLUsers()
+    def get_name_id(self):
+        return 'r2d2'
+
 
 @mock.patch('combo.utils.requests_wrapper.RequestsSession.request')
 def test_remote_regie_active_invoices_cell(mock_request, remote_regie):
diff --git a/tests/test_newsletters_cell.py b/tests/test_newsletters_cell.py
index 311d1546..30719786 100644
--- a/tests/test_newsletters_cell.py
+++ b/tests/test_newsletters_cell.py
@@ -223,9 +223,7 @@ def test_get_subscriptions_with_name_id_and_mobile(mock_get, cell, user):
 
     fake_saml_request = mock.Mock()
     fake_saml_request.user = mock.Mock(email=USER_EMAIL)
-    fake_saml_request.user.saml_identifiers = mock.Mock()
-    fake_saml_request.user.saml_identifiers.exists.return_value = True
-    fake_saml_request.user.saml_identifiers.first.return_value = mock.Mock(name_id='nameid')
+    fake_saml_request.user.get_name_id.return_value = 'nameid'
     fake_saml_request.session = {'mellon_session': {'mobile': '0607080900'}}
 
     form = NewslettersManageForm(instance=cell, request=fake_saml_request)
diff --git a/tests/test_profile.py b/tests/test_profile.py
index 57681e14..26f8b39f 100644
--- a/tests/test_profile.py
+++ b/tests/test_profile.py
@@ -13,9 +13,8 @@ pytestmark = pytest.mark.django_db
 
 @override_settings(
         KNOWN_SERVICES={'authentic': {'idp': {'title': 'IdP', 'url': 'http://example.org/'}}})
-@mock.patch('combo.public.templatetags.combo.UserSAMLIdentifier')
 @mock.patch('combo.utils.requests.get')
-def test_profile_cell(requests_get, user_saml, app, admin_user):
+def test_profile_cell(requests_get, app, admin_user):
     page = Page()
     page.save()
 
@@ -28,24 +27,9 @@ def test_profile_cell(requests_get, user_saml, app, admin_user):
             json=lambda: data,
             status_code=200)
 
-    def filter_mock(user=None):
-        assert user is admin_user
-        return mock.Mock(last=lambda: mock.Mock(name_id='123456'))
-
-    mocked_objects = mock.Mock()
-    mocked_objects.filter = mock.Mock(side_effect=filter_mock)
-    user_saml.objects = mocked_objects
+    admin_user.get_name_id = lambda: '123456'
 
     context = cell.get_cell_extra_context({'synchronous': True, 'selected_user': admin_user})
     assert context['profile_fields']['first_name']['value'] == 'Foo'
     assert context['profile_fields']['birthdate']['value'] == datetime.date(2018, 8, 10)
     assert requests_get.call_args[0][0] == 'http://example.org/api/users/123456/'
-
-    def filter_mock_missing(user=None):
-        return mock.Mock(last=lambda: None)
-
-    mocked_objects.filter = mock.Mock(side_effect=filter_mock_missing)
-
-    context = cell.get_cell_extra_context({'synchronous': True, 'selected_user': admin_user})
-    assert context['error'] == 'unknown user'
-    assert requests_get.call_count == 1  # no new call was made
diff --git a/tests/test_public.py b/tests/test_public.py
index 92efafb2..b0983734 100644
--- a/tests/test_public.py
+++ b/tests/test_public.py
@@ -813,7 +813,7 @@ def test_sub_slug(app, john_doe, jane_doe):
         assert 'XXYY' in resp.text
 
         # custom behaviour for <name_id>, it will add the SAML user to context
-        with mock.patch('combo.public.views.UserSAMLIdentifier') as user_saml:
+        with mock.patch('combo.profile.utils.UserSAMLIdentifier') as user_saml:
             class DoesNotExist(Exception):
                 pass
             user_saml.DoesNotExist = DoesNotExist
diff --git a/tests/test_requests.py b/tests/test_requests.py
index 3d56edea..4d3b3a03 100644
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -8,22 +8,18 @@ from django.utils.six.moves.urllib import parse as urlparse
 
 from combo.utils import requests, check_query, NothingInCacheException
 
-class MockSAMLUser(object):
-    name_id = 'r2d2'
-
 class MockUser(object):
     email = 'foo@example.net'
     def is_authenticated(self):
         return True
 
+    def get_name_id(self):
+        if self.samlized:
+            return 'r2d2'
+        return None
+
     def __init__(self, samlized=True):
-        class MockSAMLUsers(object):
-            def exists(self):
-                return True
-            def first(self):
-                return MockSAMLUser()
-        if samlized:
-            self.saml_identifiers = MockSAMLUsers()
+        self.samlized = samlized
 
 
 def test_nosign():
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 37011684..8ccbde0c 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -9,22 +9,18 @@ from django.test.client import RequestFactory
 from django.contrib.auth.models import AnonymousUser
 
 
-class MockSAMLUser(object):
-    name_id = 'r2&d2'
-
 class MockUser(object):
     email = 'foo=3@example.net'
     def is_authenticated(self):
         return True
 
     def __init__(self, samlized=True):
-        class MockSAMLUsers(object):
-            def exists(self):
-                return True
-            def first(self):
-                return MockSAMLUser()
-        if samlized:
-            self.saml_identifiers = MockSAMLUsers()
+        self.samlized = samlized
+
+    def get_name_id(self):
+        if self.samlized:
+            return 'r2&d2'
+        return None
 
 
 def test_crypto_url():
diff --git a/tests/test_wcs.py b/tests/test_wcs.py
index 449fe231..9add0ead 100644
--- a/tests/test_wcs.py
+++ b/tests/test_wcs.py
@@ -161,6 +161,14 @@ user2.store()
 WCS_DIR = tempfile.mkdtemp()
 WCS_PID = None
 
+
+class MockUser(object):
+    email = 'foo@example.net'
+    def is_authenticated(self):
+        return True
+    def get_name_id(self):
+        return None
+
 def run_wcs_script(script, hostname):
     script_path = os.path.join(WCS_DIR, script + '.py')
     fd = open(script_path, 'w')
@@ -345,10 +353,6 @@ def test_current_forms_cell_render(context):
     cell = WcsCurrentFormsCell(page=page, placeholder='content', order=0)
     cell.save()
 
-    class MockUser(object):
-        email = 'foo@example.net'
-        def is_authenticated(self):
-            return True
     context['request'].user = MockUser()
 
     # query should fail as nothing is cached
@@ -412,10 +416,6 @@ def test_current_forms_cell_render_single_site(context):
     cell.wcs_site = 'default'
     cell.save()
 
-    class MockUser(object):
-        email = 'foo@example.net'
-        def is_authenticated(self):
-            return True
     context['request'].user = MockUser()
 
     # query should fail as nothing is cached
@@ -506,10 +506,6 @@ def test_current_drafts_cell_render_logged_in(context):
     cell.save()
     context['synchronous'] = True # to get fresh content
 
-    class MockUser(object):
-        email = 'foo@example.net'
-        def is_authenticated(self):
-            return True
     context['request'].user = MockUser()
 
     # default is to get current forms from all wcs sites
@@ -695,20 +691,14 @@ def test_backoffice_submission_cell_render(context):
     result = cell.render(context)
     assert '/backoffice/submission/a-private-form/' not in result
 
-    class MockUser(object):
-        email = 'foo@example.net'
-        def is_authenticated(self):
-            return True
     context['request'].user = MockUser()
 
     result = cell.render(context)
     assert '/backoffice/submission/a-private-form/' not in result
 
-    class MockUser(object):
+    class MockUser2(MockUser):
         email = 'foo2@example.net'
-        def is_authenticated(self):
-            return True
-    context['request'].user = MockUser()
+    context['request'].user = MockUser2()
 
     result = cell.render(context)
     assert '/backoffice/submission/a-private-form/' in result