feat: Implement atomic transaction for activating broadcast messages …

server/broadcast/api_views.py

@@ -2,6 +2,7 @@
 from rest_framework.decorators import action, api_view, permission_classes
 from rest_framework.response import Response
 from rest_framework.permissions import IsAuthenticated, AllowAny
+from django.db import transaction
 from .models import BroadcastMessage
 from .serializers import BroadcastMessageSerializer
 from dashboard.models import UserDetails
@@ -46,8 +47,16 @@ def set_active(self, request, pk=None):
         if message.user != request.user and not request.user.is_staff:
             return Response({'error': 'Permission denied'}, status=status.HTTP_403_FORBIDDEN)
 
-        message.active = True
-        message.save()
+        with transaction.atomic():
+            message = BroadcastMessage.objects.select_for_update().get(pk=pk)
+
+            BroadcastMessage.objects.select_for_update().filter(
+                user=message.user, active=True
+            ).update(active=False)
+
+            message.active = True
+            message.save()
+
         return Response({'message': 'Message set as active'})
 
 
@@ -57,13 +66,11 @@ def get_user_broadcast(request, user_slug):
     try:
         user_details = UserDetails.objects.select_related('user').get(_slug=user_slug)
 
-        # Get active broadcast message if exists
         active_message = BroadcastMessage.objects.filter(
             user=user_details.user,
             active=True
         ).first()
 
-        # Build response with user details and active message
         response_data = {
             'username': user_details.user.username,
             'user_username': user_details.user.username,

server/broadcast/models.py

@@ -1,17 +1,23 @@
-from django.db import models
+from django.db import models, transaction
 from django.conf import settings
 
 
-# Create your models here.
 class BroadcastMessage(models.Model):
     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='messages')
     message = models.TextField()
     active = models.BooleanField(default=True)
 
     def save(self, *args, **kwargs):
         if self.active:
-            BroadcastMessage.objects.filter(user=self.user, active=True).update(active=False)
-        super().save(*args, **kwargs)
+            with transaction.atomic():
+
+                BroadcastMessage.objects.select_for_update().filter(
+                    user=self.user
+                ).update(active=False)
+                # Save this message as active
+                super().save(*args, **kwargs)
+        else:
+            super().save(*args, **kwargs)
 
     def __str__(self):
         return f'{self.user.username}: {self.message[:20]}'