control one permission with same name for each page

apps/authorization/api/v1/api.py

@@ -1,5 +1,6 @@
 from rest_framework_simplejwt.authentication import JWTAuthentication
 from rest_framework.permissions import AllowAny, IsAuthenticated
+from apps.core.exceptions import ConflictException
 from rest_framework.exceptions import APIException
 from apps.authorization.api.v1.serializers import (
     RoleSerializer,
@@ -64,6 +65,16 @@ class PermissionViewSet(viewsets.ModelViewSet):
     filter_backends = [filters.SearchFilter]
     search_fields = ['page__name', ]
 
+    def create(self, request, *args, **kwargs):
+        if self.queryset.filter(name=request.data['name'], page_id=request.data['page']).exists():
+            raise ConflictException('a permission with this page exists.')
+        serializer = self.serializer_class(data=request.data)
+        if serializer.is_valid():
+            serializer.save()
+            return Response(serializer.data, status=status.HTTP_200_OK)
+        else:
+            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+
 
 class UserRelationViewSet(viewsets.ModelViewSet):
     """ Crud Operations for User Relations """