Quick fix for OPC us server

controls-opcua/src/main/kotlin/space/kscience/controls/opcua/client/MetaBsdParser.kt

@@ -56,6 +56,7 @@ internal class MetaEnumCodec : OpcUaBinaryDataTypeCodec<Number> {
 
 internal fun opcToMeta(value: Any?): Meta = when (value) {
     null -> Meta(Null)
+    is Variant -> opcToMeta(value.value)
     is Meta -> value
     is Value -> Meta(value)
     is Number -> when (value) {
@@ -79,13 +80,18 @@ internal fun opcToMeta(value: Any?): Meta = when (value) {
         "text" put value.text?.asValue()
     }
     is DataValue -> Meta {
-        "value" put opcToMeta(value.value) // need SerializationContext to do that properly
+        val variant= opcToMeta(value.value)
+        update(variant)// need SerializationContext to do that properly
+        //TODO remove after DF 0.7.2
+        this.value =  variant.value
+        "@opc" put {
             value.statusCode?.value?.let { "status" put Meta(it.asValue()) }
             value.sourceTime?.javaInstant?.let { "sourceTime" put it.toKotlinInstant().toMeta() }
             value.sourcePicoseconds?.let { "sourcePicoseconds" put Meta(it.asValue()) }
             value.serverTime?.javaInstant?.let { "serverTime" put it.toKotlinInstant().toMeta() }
             value.serverPicoseconds?.let { "serverPicoseconds" put Meta(it.asValue()) }
         }
+    }
     is ByteString -> Meta(value.bytesOrEmpty().asValue())
     is XmlElement -> Meta(value.fragment?.asValue() ?: Null)
     is NodeId -> Meta(value.toParseableString().asValue())

controls-opcua/src/main/kotlin/space/kscience/controls/opcua/server/DeviceNameSpace.kt

@@ -2,7 +2,6 @@ package space.kscience.controls.opcua.server
 
 import kotlinx.coroutines.launch
 import kotlinx.datetime.toJavaInstant
-import kotlinx.serialization.json.Json
 import org.eclipse.milo.opcua.sdk.core.AccessLevel
 import org.eclipse.milo.opcua.sdk.core.Reference
 import org.eclipse.milo.opcua.sdk.server.Lifecycle
@@ -21,14 +20,15 @@ import org.eclipse.milo.opcua.stack.core.types.builtin.DateTime
 import org.eclipse.milo.opcua.stack.core.types.builtin.LocalizedText
 import space.kscience.controls.api.*
 import space.kscience.controls.manager.DeviceManager
+import space.kscience.controls.opcua.client.opcToMeta
 import space.kscience.dataforge.meta.Meta
-import space.kscience.dataforge.meta.MetaSerializer
 import space.kscience.dataforge.meta.ValueType
 import space.kscience.dataforge.names.Name
 import space.kscience.dataforge.names.plus
 
 
-public operator fun CachingDevice.get(propertyDescriptor: PropertyDescriptor): Meta? = getProperty(propertyDescriptor.name)
+public operator fun CachingDevice.get(propertyDescriptor: PropertyDescriptor): Meta? =
+    getProperty(propertyDescriptor.name)
 
 public suspend fun Device.read(propertyDescriptor: PropertyDescriptor): Meta = readProperty(propertyDescriptor.name)
 
@@ -38,29 +38,11 @@ https://github.com/eclipse/milo/blob/master/milo-examples/server-examples/src/ma
 
 public class DeviceNameSpace(
     server: OpcUaServer,
-    public val deviceManager: DeviceManager
+    public val deviceManager: DeviceManager,
 ) : ManagedNamespaceWithLifecycle(server, NAMESPACE_URI) {
 
     private val subscription = SubscriptionModel(server, this)
 
-    init {
-        lifecycleManager.addLifecycle(subscription)
-
-        lifecycleManager.addStartupTask {
-            nodeContext.registerHub(deviceManager, Name.EMPTY)
-        }
-
-        lifecycleManager.addLifecycle(object : Lifecycle {
-            override fun startup() {
-                server.addressSpaceManager.register(this@DeviceNameSpace)
-            }
-
-            override fun shutdown() {
-                server.addressSpaceManager.unregister(this@DeviceNameSpace)
-            }
-        })
-    }
-
     private fun UaFolderNode.registerDeviceNodes(deviceName: Name, device: Device) {
         val nodes = device.propertyDescriptors.associate { descriptor ->
             val propertyName = descriptor.name
@@ -74,14 +56,17 @@ public class DeviceNameSpace(
                         setAccessLevel(AccessLevel.READ_WRITE)
                         setUserAccessLevel(AccessLevel.READ_WRITE)
                     }
+
                     descriptor.mutable -> {
                         setAccessLevel(AccessLevel.WRITE_ONLY)
                         setUserAccessLevel(AccessLevel.WRITE_ONLY)
                     }
+
                     descriptor.readable -> {
                         setAccessLevel(AccessLevel.READ_ONLY)
                         setUserAccessLevel(AccessLevel.READ_ONLY)
                     }
+
                     else -> {
                         setAccessLevel(AccessLevel.NONE)
                         setUserAccessLevel(AccessLevel.NONE)
@@ -104,29 +89,26 @@ public class DeviceNameSpace(
             }.build()
 
             // Update initial value, but only if it is cached
-            if(device is CachingDevice) {
+            if (device is CachingDevice) {
                 device[descriptor]?.toOpc(sourceTime = null, serverTime = null)?.let {
                     node.value = it
                 }
             }
 
+            if (descriptor.mutable) {
+
                 /**
                  * Subscribe to node value changes
                  */
-            node.addAttributeObserver { _: UaNode, attributeId: AttributeId, value: Any ->
+                node.addAttributeObserver { _: UaNode, attributeId: AttributeId, value: Any? ->
                     if (attributeId == AttributeId.Value) {
-                    val meta: Meta = when (value) {
+                        val meta: Meta = opcToMeta(value)
-                        is Meta -> value
-                        is Boolean -> Meta(value)
-                        is Number -> Meta(value)
-                        is String -> Json.decodeFromString(MetaSerializer, value)
-                        else -> return@addAttributeObserver //TODO("other types not implemented")
-                    }
                         deviceManager.context.launch {
                             device.writeProperty(propertyName, meta)
                         }
                     }
                 }
+            }
 
             nodeManager.addNode(node)
             addOrganizes(node)
@@ -137,7 +119,10 @@ public class DeviceNameSpace(
         device.onPropertyChange {
             nodes[property]?.let { node ->
                 val sourceTime = time?.let { DateTime(it.toJavaInstant()) }
-                node.value = value.toOpc(sourceTime = sourceTime)
+                val newValue = value.toOpc(sourceTime = sourceTime)
+                if (node.value.value != newValue.value) {
+                    node.value = newValue
+                }
             }
         }
         //recursively add sub-devices
@@ -168,6 +153,24 @@ public class DeviceNameSpace(
         }
     }
 
+    init {
+        lifecycleManager.addLifecycle(subscription)
+
+        lifecycleManager.addStartupTask {
+            nodeContext.registerHub(deviceManager, Name.EMPTY)
+        }
+
+        lifecycleManager.addLifecycle(object : Lifecycle {
+            override fun startup() {
+                server.addressSpaceManager.register(this@DeviceNameSpace)
+            }
+
+            override fun shutdown() {
+                server.addressSpaceManager.unregister(this@DeviceNameSpace)
+            }
+        })
+    }
+
     override fun onDataItemsCreated(dataItems: List<DataItem?>?) {
         subscription.onDataItemsCreated(dataItems)
     }