fix: accept subchannel references as stored in the OSW backend

src/opensemantic/lab/_controller.py

@@ -5,7 +5,7 @@
 
 import logging
 from enum import Enum
-from typing import Any, Awaitable, Callable, Dict, List, Optional
+from typing import Any, Awaitable, Callable, Dict, List, Optional, Union
 
 from pydantic import BaseModel, ConfigDict, PrivateAttr
 
@@ -20,7 +20,9 @@
 class OpcUaDataChannel(OpcUaDataChannelMixin, _OpcUaDataChannel):
     """Enhanced v2 OpcUaDataChannel with uuid5 generation and helper methods."""
 
-    subchannels: Optional[List["OpcUaDataChannel"]] = None
+    subchannels: Optional[List[Union[str, "OpcUaDataChannel"]]] = None
+    """IRIs of the subchannels, as stored in the OSW backend. Inline channel
+    objects are accepted too, but do not round-trip through the backend."""
 
 
 class ControllerMode(str, Enum):

src/opensemantic/lab/_controller_mixin.py

@@ -159,6 +159,25 @@ async def stop(self):
         await super().stop()
         self._state = ControllerState.stopping
 
+    def get_channel_by_osw_id(self, osw_id: str):
+        """Look up a channel by osw_id across self and all subdevices.
+
+        Subchannel references are stored in the OSW backend as the osw_id of
+        a sibling channel on the same page. Accepts the full subobject IRI
+        (``Item:OSW<tool>#OSW<channel>``) as well as the bare ``OSW<channel>``
+        suffix, since only the suffix is stable across pages.
+
+        Raises ValueError if no channel with the given osw_id is found.
+        """
+        suffix = osw_id.split("#")[-1]
+        for ch in self.get_all_channels():
+            ch_osw_id = getattr(ch, "osw_id", None)
+            if ch_osw_id and (
+                ch_osw_id == osw_id or ch_osw_id.split("#")[-1] == suffix
+            ):
+                return ch
+        raise ValueError(f"No channel with osw_id '{osw_id}' found.")
+
     # -- OPC UA protocol methods --
 
     def _get_ua_data_value(
@@ -391,6 +410,12 @@ async def _handle_datachange_notification(self, node, val, data):
         # instead of being defined only on the controller's OpcUaDataChannel
         subchannels = getattr(channel, "subchannels", None)
         if subchannels and len(subchannels) > 0:
+            # Stored as osw_id references in the OSW backend, but inline
+            # channel objects are accepted as well.
+            subchannels = [
+                self.get_channel_by_osw_id(sc) if isinstance(sc, str) else sc
+                for sc in subchannels
+            ]
             srs = await self.read_channels(subchannels)
             _val = val.isoformat() if isinstance(val, datetime.datetime) else val
             val = {channel.name: _val}

src/opensemantic/lab/v1/_controller.py

@@ -4,7 +4,7 @@
 """
 
 import logging
-from typing import Any, Awaitable, Callable, Dict, List, Optional
+from typing import Any, Awaitable, Callable, Dict, List, Optional, Union
 
 from pydantic import ConfigDict, PrivateAttr
 
@@ -19,7 +19,9 @@
 class OpcUaDataChannel(OpcUaDataChannelMixin, _OpcUaDataChannel):
     """Enhanced v1 OpcUaDataChannel with uuid5 generation and helper methods."""
 
-    subchannels: Optional[List["OpcUaDataChannel"]] = None
+    subchannels: Optional[List[Union[str, "OpcUaDataChannel"]]] = None
+    """IRIs of the subchannels, as stored in the OSW backend. Inline channel
+    objects are accepted too, but do not round-trip through the backend."""
 
 
 try:

tests/test_controller.py

@@ -129,6 +129,55 @@ def test_channel_subchannels():
     assert main.subchannels[0].name == "SubChannel"
 
 
+def test_channel_subchannels_as_iris():
+    """Subchannels stored in the OSW backend are IRIs, not inline objects."""
+    main = OpcUaDataChannel(
+        uuid=str(compute_scoped_uuid(_TEST_SERVER_UUID, "ns=2;s=Main")),
+        node_id="ns=2;s=Main",
+        name="MainChannel",
+        subchannels=["Item:OSWaaa#OSWbbb"],
+    )
+    assert main.subchannels == ["Item:OSWaaa#OSWbbb"]
+
+
+def test_server_resolves_subchannel_iris(server_with_channels):
+    """A subchannel reference resolves to the channel object it points at."""
+    server = server_with_channels
+    press = server.get_channel_by_name("Pressure")
+    assert server.get_channel_by_osw_id(press.osw_id) is press
+    # The bare OSW<uuid> suffix resolves as well
+    assert server.get_channel_by_osw_id(press.osw_id.split("#")[-1]) is press
+
+
+def test_server_resolves_subchannel_iri_of_subdevice(server_with_channels):
+    """Resolution spans the whole subdevice hierarchy."""
+    server = server_with_channels
+    sub_temp = server.get_channel_by_name("SubTemperature")
+    assert server.get_channel_by_osw_id(sub_temp.osw_id) is sub_temp
+
+
+def test_server_resolve_unknown_osw_id_raises(server_with_channels):
+    with pytest.raises(ValueError):
+        server_with_channels.get_channel_by_osw_id("Item:OSWaaa#OSWbbb")
+
+
+def test_subchannel_references_roundtrip(server_with_channels):
+    """Subchannel osw_ids survive serialization and still resolve on reload."""
+    import json
+
+    server = server_with_channels
+    temp = server.get_channel_by_name("Temperature")
+    press = server.get_channel_by_name("Pressure")
+    temp.subchannels = [press.osw_id]
+
+    reloaded = OpcUaServer(**json.loads(server.model_dump_json(exclude_none=True)))
+    reloaded_temp = reloaded.get_channel_by_name("Temperature")
+    assert reloaded_temp.subchannels == [press.osw_id]
+    assert reloaded.get_channel_by_osw_id(reloaded_temp.subchannels[0]).name == (
+        "Pressure"
+    )
+
+
 # -- Subobject ID tests --
 
 
@@ -383,6 +432,32 @@ def test_v1_channel_subchannels():
     assert main.subchannels[0].name == "V1SubChannel"
 
 
+def test_v1_channel_subchannels_as_iris():
+    main = OpcUaDataChannel_v1(
+        uuid=str(compute_scoped_uuid(_TEST_SERVER_UUID, "ns=2;s=V1Main")),
+        node_id="ns=2;s=V1Main",
+        name="V1MainChannel",
+        subchannels=["Item:OSWaaa#OSWbbb"],
+    )
+    assert main.subchannels == ["Item:OSWaaa#OSWbbb"]
+
+
+def test_v1_server_resolves_subchannel_iris():
+    ch = OpcUaDataChannel_v1(
+        uuid=str(compute_scoped_uuid(_TEST_SERVER_UUID, "ns=2;s=V1Press")),
+        node_id="ns=2;s=V1Press",
+        name="V1Pressure",
+    )
+    server = OpcUaServer_v1(
+        uuid=_TEST_SERVER_UUID,
+        name="V1Server",
+        label=[Label(text="V1", lang="en")],
+        url="opc.tcp://localhost:48402",
+        data_channels=[ch],
+    )
+    assert server.get_channel_by_osw_id(ch.osw_id) is server.data_channels[0]
+
+
 # -- v1 OpcUaServer tests --