Only remove subscriptions specific to a client when closing a client session

asyncua/server/internal_session.py

@@ -37,6 +37,7 @@ class InternalSession:
         self.state = SessionState.Created
         self.session_id = ua.NodeId(self._counter)
         InternalSession._counter += 1
+        self.subscriptions = []
         self.auth_token = ua.NodeId(self._auth_counter)
         InternalSession._auth_counter += 1
         self.logger.info('Created internal session %s', self.name)
@@ -63,7 +64,7 @@ class InternalSession:
     async def close_session(self, delete_subs=True):
         self.logger.info('close session %s', self.name)
         self.state = SessionState.Closed
-        await self.delete_subscriptions(list(self.subscription_service.subscriptions.keys()))
+        await self.delete_subscriptions(self.subscriptions)
 
     def activate_session(self, params):
         self.logger.info('activate session')
@@ -119,6 +120,7 @@ class InternalSession:
 
     async def create_subscription(self, params, callback=None):
         result = await self.subscription_service.create_subscription(params, callback)
+        self.subscriptions.append(result.SubscriptionId)
         return result
 
     async def create_monitored_items(self, params: ua.CreateMonitoredItemsParameters):

dev_requirements.txt

@@ -1,3 +1,4 @@
 pytest
 pytest-asyncio
 coverage
+pytest-cov

tests/test_server.py

@@ -106,6 +106,31 @@ async def test_historize_variable(server):
     await var.set_value(3.0)
     await server.iserver.disable_history_data_change(var)
 
+async def test_multiple_clients_with_subscriptions(server):
+    """
+    Tests that multiple clients can subscribe, and when one client disconnects, the other
+    still maintains it's subscription
+    """
+    class SubscriptionHandler:
+        def datachange_notification(self, node, val, data):
+            pass
+    sub_handler = SubscriptionHandler()
+    client1 = Client(server.endpoint.geturl())
+    client2 = Client(server.endpoint.geturl())
+
+    o = server.get_objects_node()
+    var = await o.add_variable(3, "some_variable", 1.0)
+    async with client1:
+        async with client2:
+            sub1 = await client1.create_subscription(100, sub_handler)
+            sub2 = await client2.create_subscription(100, sub_handler)
+            await sub1.subscribe_data_change(var)
+            await sub2.subscribe_data_change(var)
+            assert len(server.iserver.subscription_service.subscriptions) == 2
+        # When client2 disconnects, client1 should still keep it's subscription.
+        assert len(server.iserver.subscription_service.subscriptions) == 1
+    assert len(server.iserver.subscription_service.subscriptions) == 0
+
 
 async def test_historize_events(server):
     srv_node = server.get_node(ua.ObjectIds.Server)