Improvements

api/sync.py

@@ -10,6 +10,7 @@ from django.db.models import Q
 from django.core.exceptions import ObjectDoesNotExist
 
 from collections import defaultdict
+from urllib.parse import unquote
 
 from .utils import build_serializer_class, get_data, get_serialized_data
 
@@ -38,14 +39,19 @@ class DataApi(APIView):
             instance = get_data('tournaments', model_name, data_id)
 
             if model_operation == 'DELETE':
-                parent_model, parent_id = instance.get_parent_reference()
+                # parent_model, parent_id = instance.get_parent_reference()
-                return self.delete_and_save_log(request, data_id, model_operation, model_name, store_id, now)
+                instance = get_data('tournaments', model_name, data_id)
+                instance.delete()
+                return Response(status=status.HTTP_204_NO_CONTENT)
+                # return self.delete_and_save_log(request, data_id, model_operation, model_name, store_id, now)
             else: # PUT
                 serializer = serializer_class(instance, data=data, context={'request': request})
                 if serializer.is_valid():
                     if instance.last_update <= serializer.validated_data.get('last_update'):
                         print('>>> update')
-                        return self.save_and_create_log(request, serializer, model_operation, model_name, store_id, now)
+                        serializer.save()
+                        return Response(serializer.data, status=status.HTTP_200_OK)
+                        # return self.save_and_create_log(request, serializer, model_operation, model_name, store_id, now)
                     else:
                         print('>>> return 203')
                         return Response(serializer.data, status=status.HTTP_203_NON_AUTHORITATIVE_INFORMATION)
@@ -55,89 +61,36 @@ class DataApi(APIView):
             print('>>> insert')
             serializer = serializer_class(data=data, context={'request': request})
             if serializer.is_valid():
-                return self.save_and_create_log(request, serializer, model_operation, model_name, store_id, now)
+                serializer.save()
+                return Response(serializer.data, status=status.HTTP_201_CREATED)
+                # return self.save_and_create_log(request, serializer, model_operation, model_name, store_id, now)
             else:
                 return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
-    def save_and_create_log(self, request, serializer, model_operation, model_name, store_id, date):
-
-        instance = serializer.save()
-
-        self.save_model_log(
-            user=request.user,
-            model_operation=model_operation,
-            model_name=model_name,
-            model_id=instance.id,
-            store_id=store_id,
-            date=date
-        )
-
-        self.update_linked_data_access(instance, date)
-
-        return Response(serializer.data, status=status.HTTP_201_CREATED)
-
-    def delete_and_save_log(self, request, data_id, model_operation, model_name, store_id, date):
-
-        instance = get_data('tournaments', model_name, data_id)
-        self.update_linked_data_access(instance, date)
-
-        instance.delete()
-
-        # We delete all previous logs linked to the instance because they won't be needed anymore
-        ModelLog.objects.filter(model_id=data_id).delete()
-
-        self.save_model_log(
-            user=request.user,
-            model_operation=model_operation,
-            model_name=model_name,
-            model_id=data_id,
-            store_id=store_id,
-            date=date
-        )
-
-        return Response(status=status.HTTP_204_NO_CONTENT)
-
-    def update_linked_data_access(self, instance, date):
-        related_instances = instance.related_instances()
-        related_ids = [ri.id for ri in instance.related_instances()]
-        related_ids.append(instance.id)
-        data_access_list = DataAccess.objects.filter(model_id__in=related_ids)
-
-        for data_access in data_access_list:
-            data_access.last_hierarchy_update = date
-            data_access.save()
-
-    def save_model_log(self, user, model_operation, model_name, model_id, store_id, date):
-        existing_log = ModelLog.objects.filter(user=user, model_id=model_id, operation=model_operation).first()
-        if existing_log:
-            existing_log.date = date
-            existing_log.model_operation = model_operation
-            existing_log.save()
-        else:
-            model_log = ModelLog()
-            model_log.user = user
-            model_log.operation = model_operation
-            model_log.date = date
-            model_log.model_name = model_name
-            model_log.model_id = model_id
-            model_log.store_id = store_id
-            model_log.save()
-
     def get(self, request, *args, **kwargs):
-        last_update = request.query_params.get('last_update')
+        last_update_str = request.query_params.get('last_update')
-        if not last_update:
+        decoded_last_update = unquote(last_update_str)  # Decodes %2B into +
+
+        # print(f'last_update_str = {last_update_str}')
+        # print(f'decoded_last_update = {decoded_last_update}')
+        if not decoded_last_update:
             return Response({"error": "last_update parameter is required"}, status=status.HTTP_400_BAD_REQUEST)
+        try:
+            last_update = timezone.datetime.fromisoformat(decoded_last_update)
+        except ValueError:
+            return Response({"error": f"Invalid date format for last_update: {decoded_last_update}"}, status=status.HTTP_400_BAD_REQUEST)
 
         print(f'/data GET: {last_update}')
 
         logs = self.query_model_logs(last_update, request.user)
+        print(f'>>> log count = {len(logs)}')
 
         updates = defaultdict(dict)
         deletions = defaultdict(list)
 
-        # print(f'>>> log count = {len(logs)}')
+        last_log_date = None
-
         for log in logs:
+            last_log_date = log.date
             try:
                 if log.operation in ['POST', 'PUT']:
                     data = get_serialized_data('tournaments', log.model_name, log.model_id)
@@ -156,7 +109,7 @@ class DataApi(APIView):
                     # instance = model.objects.get(id=log.model_id)
                     self.add_children_recursively(instance, updates)
                     self.add_parents_recursively(instance, updates)
-                elif log.operation == 'delete data access signal':
+                elif log.operation == 'REVOKE_ACCESS':
                     print(f'revoke access {log.model_id} - {log.store_id}')
                     deletions[log.model_name].append({'model_id': log.model_id, 'store_id': log.store_id})
             except ObjectDoesNotExist:
@@ -172,38 +125,37 @@ class DataApi(APIView):
 
         response_data = {
             "updates": dict(updates),
-            "deletions": dict(deletions)
+            "deletions": dict(deletions),
-        }
+            "date": last_log_date
+            }
 
         return Response(response_data, status=status.HTTP_200_OK)
 
     def query_model_logs(self, last_update, user):
-        try:
+        # print(f'last_update = {last_update}')
-            last_update = timezone.datetime.fromisoformat(last_update)
+        log_query = Q(date__gt=last_update) & Q(users=user)
-        except ValueError:
+        return ModelLog.objects.filter(log_query).order_by('date')
-            return Response({"error": f"Invalid date format for last_update: {last_update}"}, status=status.HTTP_400_BAD_REQUEST)
 
         # get recently modified DataAccess
-        data_access_query = Q(last_hierarchy_update__gt=last_update) & (Q(shared_with__in=[user]) | Q(owner=user))
+        # data_access_query = Q(last_hierarchy_update__gt=last_update) & (Q(shared_with__in=[user]) | Q(owner=user))
-        data_access_list = DataAccess.objects.filter(data_access_query) #.values_list('model_id', flat=True)
+        # data_access_list = DataAccess.objects.filter(data_access_query) #.values_list('model_id', flat=True)
 
         # print(f'>> da count = {len(data_access_list)}')
 
-        # get ids of all recently updated related instances of each shared data
+        # # get ids of all recently updated related instances of each shared data
-        model_ids = []
+        # model_ids = []
-        for data_access in data_access_list:
+        # for data_access in data_access_list:
-            model_ids.append(data_access.model_id)
+        #     model_ids.append(data_access.model_id)
-            try:
+        #     try:
-                instance = get_data('tournaments', data_access.model_name, data_access.model_id)
+        #         instance = get_data('tournaments', data_access.model_name, data_access.model_id)
-                related_instances = instance.related_instances()
+        #         related_instances = instance.related_instances()
-                related_ids = [ri.id for ri in instance.related_instances() if ri.last_update > last_update]
+        #         related_ids = [ri.id for ri in instance.related_instances() if ri.last_update > last_update]
-                model_ids.extend(related_ids)
+        #         model_ids.extend(related_ids)
-            except ObjectDoesNotExist:
+        #     except ObjectDoesNotExist:
-                pass
+        #         pass
 
         # get all ModelLog list since the last_update, from the user and from the data he has access to
-        log_query = Q(date__gt=last_update) & (Q(user=user) | Q(model_id__in=model_ids))
+
-        return ModelLog.objects.filter(log_query).order_by('date')
 
     def add_children_recursively(self, instance, updates):
         """

api/utils.py

@@ -9,7 +9,7 @@ def is_valid_email(email):
 def build_serializer_class(source):
 
     # Remove the 's' character at the end if present
-    if source.endswith('s'):
+    if source.endswith('s') and not source.endswith('ss'):
         source = source[:-1]
 
     # Capitalize words separated by a dash

api/views.py

@@ -313,5 +313,5 @@ class DataAccessViewSet(viewsets.ModelViewSet):
 
     def get_queryset(self):
         if self.request.user:
-            return self.queryset.filter(owner=self.request.user)
+            return self.queryset.filter(Q(owner=self.request.user) | Q(shared_with__in=[self.request.user]))
         return []

padelclub_backend/settings_app.py

@@ -1,6 +1,7 @@
 
 # Rest Framework configuration
 REST_FRAMEWORK = {
+    'DATETIME_FORMAT': "%Y-%m-%dT%H:%M:%S%z",
     # Use Django's standard `django.contrib.auth` permissions,
     # or allow read-only access for unauthenticated users.
     'DEFAULT_PERMISSION_CLASSES': [

tournaments/admin.py

@@ -1,10 +1,11 @@
 from django.contrib import admin
+from django.utils import timezone
 
 from tournaments.models import team_registration
 from tournaments.models.data_access import DataAccess
 from tournaments.models.device_token import DeviceToken
 
-from .models import Club, TeamScore, Tournament, CustomUser, Event, Round, GroupStage, Match, TeamRegistration, PlayerRegistration, Purchase, Court, DateInterval, FailedApiCall, Log, ModelLog
+from .models import BaseModel, Club, TeamScore, Tournament, CustomUser, Event, Round, GroupStage, Match, TeamRegistration, PlayerRegistration, Purchase, Court, DateInterval, FailedApiCall, Log, ModelLog
 from django.contrib.auth.admin import UserAdmin
 from django.contrib.auth.forms import UserCreationForm, UserChangeForm
 
@@ -12,6 +13,12 @@ from .forms import CustomUserCreationForm, CustomUserChangeForm
 
 from .filters import TeamScoreTournamentListFilter, MatchTournamentListFilter, SimpleTournamentListFilter, MatchTypeListFilter, SimpleIndexListFilter
 
+class AutoUpdateAdmin(admin.ModelAdmin):
+    def save_model(self, request, obj, form, change):
+        if isinstance(obj, BaseModel):
+            obj.last_updated_by = request.user
+            obj.last_update = timezone.now()
+        super().save_model(request, obj, form, change)
 
 class CustomUserAdmin(UserAdmin):
     form = CustomUserChangeForm
@@ -37,72 +44,77 @@ class CustomUserAdmin(UserAdmin):
         ),
     ]
 
-class EventAdmin(admin.ModelAdmin):
+class EventAdmin(AutoUpdateAdmin):
     list_display = ['creation_date', 'name', 'club', 'creator']
     list_filter = ['creator']
+    ordering = ['-creation_date']
 
-class TournamentAdmin(admin.ModelAdmin):
+class TournamentAdmin(AutoUpdateAdmin):
     list_display = ['display_name', 'event', 'is_private', 'start_date', 'payment', 'is_canceled']
     list_filter = ['is_deleted']
 
-class TeamRegistrationAdmin(admin.ModelAdmin):
+class TeamRegistrationAdmin(AutoUpdateAdmin):
     list_display = ['player_names', 'group_stage_position', 'name', 'tournament']
     list_filter = [SimpleTournamentListFilter]
 
-class TeamScoreAdmin(admin.ModelAdmin):
+class TeamScoreAdmin(AutoUpdateAdmin):
     list_display = ['team_registration', 'score', 'walk_out', 'match']
     list_filter = [TeamScoreTournamentListFilter]
 
-class RoundAdmin(admin.ModelAdmin):
+class RoundAdmin(AutoUpdateAdmin):
     list_display = ['tournament', 'name', 'index', 'parent']
     list_filter = [SimpleTournamentListFilter, SimpleIndexListFilter]
     search_fields = ['id']
 
-class PlayerRegistrationAdmin(admin.ModelAdmin):
+class PlayerRegistrationAdmin(AutoUpdateAdmin):
     list_display = ['first_name', 'last_name', 'licence_id', 'rank']
     search_fields = ('first_name', 'last_name')
 
-class MatchAdmin(admin.ModelAdmin):
+class MatchAdmin(AutoUpdateAdmin):
     list_display = ['__str__', 'round', 'group_stage', 'start_date', 'index']
     list_filter = [MatchTypeListFilter, MatchTournamentListFilter, SimpleIndexListFilter]
 
-class GroupStageAdmin(admin.ModelAdmin):
+class GroupStageAdmin(AutoUpdateAdmin):
     list_display = ['tournament', 'index', 'start_date']
     list_filter = [SimpleTournamentListFilter]
 
-class ClubAdmin(admin.ModelAdmin):
+class ClubAdmin(AutoUpdateAdmin):
     list_display = ['name', 'acronym', 'city', 'creator', 'events_count', 'broadcast_code']
     search_fields = ('name', 'acronym')
 
-class PurchaseAdmin(admin.ModelAdmin):
+class PurchaseAdmin(AutoUpdateAdmin):
     list_display = ['user', 'identifier', 'product_id', 'quantity', 'purchase_date', 'revocation_date']
 
-class CourtAdmin(admin.ModelAdmin):
+class CourtAdmin(AutoUpdateAdmin):
     list_display = ['index', 'name', 'club']
 
-class DateIntervalAdmin(admin.ModelAdmin):
+class DateIntervalAdmin(AutoUpdateAdmin):
     list_display = ['court_index', 'event']
 
-class FailedApiCallAdmin(admin.ModelAdmin):
+class FailedApiCallAdmin(AutoUpdateAdmin):
     list_display = ['date', 'user', 'type', 'error']
     list_filter = ['user']
 
-class LogAdmin(admin.ModelAdmin):
+class LogAdmin(AutoUpdateAdmin):
     list_display = ['date', 'user', 'message']
     list_filter = ['user']
 
-class DeviceTokenAdmin(admin.ModelAdmin):
+class DeviceTokenAdmin(AutoUpdateAdmin):
     list_display = ['user', 'value']
 
 class ModelLogAdmin(admin.ModelAdmin):
-    list_display = ['user', 'date', 'operation', 'model_id', 'model_name']
+    list_display = ['get_users', 'date', 'operation', 'model_id', 'model_name']
-    list_filter = ['user']
+    list_filter = ['users']
     ordering = ['-date']
 
-class DataAccessAdmin(admin.ModelAdmin):
+    @admin.display(description='Users')
-    list_display = ['owner', 'get_shared_users', 'model_name', 'model_id', 'last_hierarchy_update']
+    def get_users(self, obj):
+        return ", ".join([str(item) for item in obj.users.all()])
+
+class DataAccessAdmin(AutoUpdateAdmin):
+    list_display = ['owner', 'get_shared_users', 'model_name', 'model_id']
     list_filter = ['owner', 'shared_with']
-    ordering = ['-last_hierarchy_update']
+    ordering = ['-granted_at']
 
     @admin.display(description='Shared with')
     def get_shared_users(self, obj):

tournaments/migrations/0101_remove_modellog_user_modellog_users.py

@@ -0,0 +1,23 @@
+# Generated by Django 5.1 on 2024-11-26 09:48
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tournaments', '0100_club_last_updated_by_court_last_updated_by_and_more'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='modellog',
+            name='user',
+        ),
+        migrations.AddField(
+            model_name='modellog',
+            name='users',
+            field=models.ManyToManyField(blank=True, related_name='model_logs', to=settings.AUTH_USER_MODEL),
+        ),
+    ]

tournaments/migrations/0102_remove_dataaccess_last_hierarchy_update.py

@@ -0,0 +1,17 @@
+# Generated by Django 5.1 on 2024-11-26 10:33
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tournaments', '0101_remove_modellog_user_modellog_users'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='dataaccess',
+            name='last_hierarchy_update',
+        ),
+    ]

tournaments/models/data_access.py

@@ -14,10 +14,13 @@ class DataAccess(BaseModel):
     model_name = models.CharField(max_length=50)
     model_id = models.UUIDField()
     granted_at = models.DateTimeField(auto_now_add=True)
-    last_hierarchy_update = models.DateTimeField(default=timezone.now)
+    # last_hierarchy_update = models.DateTimeField(default=timezone.now)
 
-    def create_access_log(self, user, operation):
+    def create_revoke_access_log(self):
-        """Create a single access log for a specific user"""
+        self.create_access_log(self.shared_with.all(), 'REVOKE_ACCESS')
+
+    def create_access_log(self, users, operation):
+        """Create an access log for a list of users """
         model_class = apps.get_model('tournaments', self.model_name)
         try:
             obj = model_class.objects.get(id=self.model_id)
@@ -25,19 +28,19 @@ class DataAccess(BaseModel):
             if isinstance(obj, SideStoreModel):
                 store_id = obj.store_id
 
-            existing_log = ModelLog.objects.filter(user=user, model_id=self.model_id, operation=operation).first()
+            existing_log = ModelLog.objects.filter(users__in=users, model_id=self.model_id, operation=operation).first()
             if existing_log:
                 existing_log.date = timezone.now()
                 existing_log.model_operation = operation
                 existing_log.save()
             else:
-                ModelLog.objects.create(
+                model_log = ModelLog.objects.create(
-                    user=user,
                     model_id=self.model_id,
                     model_name=self.model_name,
                     operation=operation,
                     date=timezone.now(),
                     store_id=store_id
                 )
+                model_log.users.set(users)
         except ObjectDoesNotExist:
             pass

tournaments/models/model_log.py

@@ -4,7 +4,7 @@ from . import ModelOperation
 
 class ModelLog(models.Model):
     id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=True)
-    user = models.ForeignKey('CustomUser', blank=True, null=True, on_delete=models.SET_NULL, related_name='model_logs')
+    users = models.ManyToManyField('CustomUser', related_name='model_logs', blank=True)
     model_id = models.UUIDField()
     operation = models.CharField(choices=ModelOperation.choices, max_length=50)
     date = models.DateTimeField()

tournaments/signals.py

@@ -1,6 +1,6 @@
 import random
 import string
-from django.db.models.signals import post_save, pre_delete, post_delete, m2m_changed
+from django.db.models.signals import pre_save, post_save, pre_delete, post_delete, m2m_changed
 from django.db.transaction import DatabaseError
 from django.dispatch import receiver
 from django.conf import settings
@@ -8,30 +8,46 @@ from django.apps import apps
 from django.utils import timezone
 from django.db.models import Q
 
-from .models import Club, FailedApiCall, CustomUser, Log, DataAccess, ModelLog, BaseModel
+from .models import Club, FailedApiCall, CustomUser, Log, DataAccess, ModelLog, ModelOperation, BaseModel, SideStoreModel
 import requests
 
 from channels.layers import get_channel_layer
 from asgiref.sync import async_to_sync
 
+from threading import Timer
+from functools import partial
+
 # Synchronization
 
+@receiver([pre_save, pre_delete])
+def synchronization_prepare(sender, instance, created=False, **kwargs):
+
+    if not isinstance(instance, BaseModel):
+        return
+    if sender in [FailedApiCall, Log, ModelLog]:
+        return
+
+    save_model_log_if_possible(instance, kwargs.get('signal'), created)
+    # if not isinstance(instance, DataAccess):
+    #     update_data_access(instance)
+
 @receiver([post_save, post_delete])
-def synchronization_notifications(sender, instance, **kwargs):
+def synchronization_notifications(sender, instance, created=False, **kwargs):
     """
     Signal handler that sends notifications through WebSocket channels when model instances are saved or deleted.
     The function creates a WebSocket group name for each affected user and sends a sync update message
     to all clients connected to that group.
     """
 
+    if not isinstance(instance, BaseModel):
+        return
     if sender in [FailedApiCall, Log, ModelLog]:
         return
 
-    if kwargs.get('signal') == post_delete:
+    # print(f'*** signals {sender}')
-        delete_data_access_if_necessary(instance.id)
+    notify_impacted_users(instance, kwargs.get('signal'))
-
-    print(f'*** signals {sender}')
 
+def notify_impacted_users(instance, signal):
     user_ids = set()
     # add impacted users
     if isinstance(instance, CustomUser):
@@ -42,64 +58,126 @@ def synchronization_notifications(sender, instance, **kwargs):
             user_ids.add(owner.id)
 
     if isinstance(instance, BaseModel):
-        data_access_query = Q(model_id=instance.id)
+        if instance._users_to_notify is not None:
-        if kwargs.get('signal') != post_delete:
+            user_ids.update(instance._users_to_notify)
-            # when deleting objects, accessing reference generates DoesNotExist exceptions
+        else:
-
+            print('no users to notify')
-            parent_model, data_access_reference_id = instance.get_parent_reference()
-            if data_access_reference_id is not None:
-                data_access_query |= Q(model_id=data_access_reference_id)
-
-        # look for users through data access objects
-        data_access_list = DataAccess.objects.filter(data_access_query)
-        for data_access in data_access_list:
-            user_ids.add(data_access.owner.id)
-            for shared_user in data_access.shared_with.all():
-                user_ids.add(shared_user.id)
 
+    print(f'notify: {user_ids}')
     for user_id in user_ids:
         send_user_message(user_id)
 
-def delete_data_access_if_necessary(model_id):
+def save_model_log_if_possible(instance, signal, created):
-    DataAccess.objects.filter(model_id=model_id).delete()
+    user = instance.last_updated_by
+    if user is not None:
+        if signal == post_save or signal == pre_save:
+            if created:
+                operation = ModelOperation.POST
+            else:
+                operation = ModelOperation.PUT
+        else:
+            operation = ModelOperation.DELETE
 
-def send_user_message(user_id):
+        model_name = instance.__class__.__name__
-    group_name = f"sync_{user_id}"
+        store_id = None
-    print(f">>> send to group {group_name}")
+        if isinstance(instance, SideStoreModel):
+            store_id = instance.store_id
 
-    # Send to all clients in the sync group
+        if operation == ModelOperation.DELETE: # delete now unnecessary logs
-    channel_layer = get_channel_layer()
+            ModelLog.objects.filter(model_id=instance.id).delete()
-    async_to_sync(channel_layer.group_send)(
+
-        group_name, {"type": "sync.update", "message": "hello"}
+        users = {user}
-    )
+        data_access_list = related_data_access(instance)
+        for data_access in data_access_list:
+            users.update(data_access.shared_with.all())
+        if isinstance(instance, DataAccess):
+            users.add(instance.owner)
+            users.update(instance.shared_with.all())
+
+        user_ids = [user.id for user in users]
+
+        print(f'users to notify: {user_ids}')
+        instance._users_to_notify = user_ids # save this for the post_save signal
+        save_model_log(users, operation, model_name, instance.id, store_id)
+
+    else:
+        print('>>> Model Log could not be created because instance.last_updated_by is None')
+
+def save_model_log(users, model_operation, model_name, model_id, store_id):
+    now = timezone.now()
+    existing_log = ModelLog.objects.filter(users__in=users, model_id=model_id, operation=model_operation).first()
+    if existing_log:
+        existing_log.date = now
+        existing_log.model_operation = model_operation
+        existing_log.save()
+    else:
+        model_log = ModelLog()
+        model_log.operation = model_operation
+        model_log.date = now
+        model_log.model_name = model_name
+        model_log.model_id = model_id
+        model_log.store_id = store_id
+        model_log.save()
+        model_log.users.set(users)
+
+def related_data_access(instance):
+    related_instances = instance.related_instances()
+    related_ids = [ri.id for ri in instance.related_instances()]
+    related_ids.append(instance.id)
+    return DataAccess.objects.filter(model_id__in=related_ids)
+
+# def update_data_access(instance):
+#     data_access_list = related_data_access(instance)
+
+#     for data_access in data_access_list:
+#         date = timezone.now() if instance.last_update is None else instance.last_update
+#         data_access.last_hierarchy_update = date
+#         data_access.save()
+
+def delete_data_access_if_necessary(model_id):
+    DataAccess.objects.filter(model_id=model_id).delete()
 
 @receiver(m2m_changed, sender=DataAccess.shared_with.through)
 def handle_shared_with_changes(sender, instance, action, pk_set, **kwargs):
+
+    users = CustomUser.objects.filter(id__in=pk_set)
+
     if action == "post_add":
-        for user_id in pk_set:
+        instance.create_access_log(users, 'GRANT_ACCESS')
-            user = CustomUser.objects.get(id=user_id)
-            instance.create_access_log(user, 'GRANT_ACCESS')
-            send_user_message(user_id)
     elif action == "post_remove":
-        for user_id in pk_set:
+        instance.create_access_log(users, 'REVOKE_ACCESS')
-            user = CustomUser.objects.get(id=user_id)
+
-            instance.create_access_log(user, 'REVOKE_ACCESS')
+    for user_id in pk_set:
-            send_user_message(user_id)
+        send_user_message(user_id)
+
+def send_user_message(user_id):
+
+    if not hasattr(send_user_message, '_buffer'):
+        send_user_message._buffer = set()
+        send_user_message._timer = None
+
+    send_user_message._buffer.add(user_id)
+
+    if send_user_message._timer:
+        send_user_message._timer.cancel()
+
+    def send_buffered_messages():
+        channel_layer = get_channel_layer()
+        for buffered_id in send_user_message._buffer:
+            group_name = f"sync_{buffered_id}"
+            print(f">>> send to group {group_name}")
+            async_to_sync(channel_layer.group_send)(
+                group_name, {"type": "sync.update", "message": "hello"}
+            )
+        send_user_message._buffer.clear()
+        send_user_message._timer = None
+
+    send_user_message._timer = Timer(0.1, send_buffered_messages)
+    send_user_message._timer.start()
 
 @receiver(pre_delete, sender=DataAccess)
 def revoke_access_after_delete(sender, instance, **kwargs):
-    for user in instance.shared_with.all():
+    instance.create_revoke_access_log()
-        instance.create_access_log(user, 'REVOKE_ACCESS')
-
-#     # Store the users in a temporary attribute that we can access after deletion
-#     instance._users_to_revoke = list(instance.shared_with.all())
-
-# @receiver(post_delete, sender=DataAccess)
-# def revoke_access_after_delete(sender, instance, **kwargs):
-#     # Create revoke logs for all previously stored users
-#     if hasattr(instance, '_users_to_revoke'):
-#         for user in instance._users_to_revoke:
-#             instance.create_access_log(user, 'REVOKE_ACCESS')
 
 # Others