Add port demo. Nullable properties

controls-core/src/commonMain/kotlin/space/kscience/controls/api/Device.kt

@@ -57,7 +57,7 @@ public interface Device : Closeable, ContextAware, CoroutineScope {
 
     /**
      * Set property [value] for a property with name [propertyName].
-     * In rare cases could suspend if the [Device] supports command queue and it is full at the moment.
+     * In rare cases could suspend if the [Device] supports command queue, and it is full at the moment.
      */
     public suspend fun writeProperty(propertyName: String, value: Meta)
 
@@ -101,7 +101,7 @@ public suspend fun Device.getOrReadProperty(propertyName: String): Meta =
  *
  * TODO currently this
  */
-public fun Device.getProperties(): Meta = Meta {
+public fun Device.getAllProperties(): Meta = Meta {
     for (descriptor in propertyDescriptors) {
         setMeta(Name.parse(descriptor.name), getProperty(descriptor.name))
     }

controls-core/src/commonMain/kotlin/space/kscience/controls/api/Socket.kt

@@ -7,7 +7,7 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.launch
 
 /**
- * A generic bi-directional sender/receiver object
+ * A generic bidirectional sender/receiver object
  */
 public interface Socket<T> : Closeable {
     /**

controls-core/src/commonMain/kotlin/space/kscience/controls/ports/Port.kt

@@ -6,11 +6,19 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.receiveAsFlow
 import space.kscience.controls.api.Socket
 import space.kscience.dataforge.context.*
+import space.kscience.dataforge.misc.Type
 import kotlin.coroutines.CoroutineContext
 
 public interface Port : ContextAware, Socket<ByteArray>
 
-public typealias PortFactory = Factory<Port>
+@Type(PortFactory.TYPE)
+public interface PortFactory: Factory<Port>{
+    public val type: String
+
+    public companion object{
+        public const val TYPE: String = "controls.port"
+    }
+}
 
 public abstract class AbstractPort(
     override val context: Context,
@@ -64,12 +72,10 @@ public abstract class AbstractPort(
 
     /**
      * Raw flow of incoming data chunks. The chunks are not guaranteed to be complete phrases.
-     * In order to form phrases some condition should used on top of it.
+     * In order to form phrases some condition should be used on top of it.
      * For example [delimitedIncoming] generates phrases with fixed delimiter.
      */
-    override fun receiving(): Flow<ByteArray> {
+    override fun receiving(): Flow<ByteArray> = incoming.receiveAsFlow()
-        return incoming.receiveAsFlow()
-    }
 
     override fun close() {
         outgoing.close()

controls-core/src/commonMain/kotlin/space/kscience/controls/ports/Ports.kt

@@ -0,0 +1,34 @@
+package space.kscience.controls.ports
+
+import space.kscience.dataforge.context.*
+import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.meta.string
+import kotlin.reflect.KClass
+
+public class Ports : AbstractPlugin() {
+
+    override val tag: PluginTag get() = Companion.tag
+
+    private val portFactories by lazy {
+        context.gather<PortFactory>(PortFactory.TYPE)
+    }
+
+    private val portCache = mutableMapOf<Meta, Port>()
+
+    public fun buildPort(meta: Meta): Port = portCache.getOrPut(meta) {
+        val type by meta.string { error("Port type is not defined") }
+        val factory = portFactories.values.firstOrNull { it.type == type }
+            ?: error("Port factory for type $type not found")
+        factory.build(context, meta)
+    }
+
+    public companion object : PluginFactory<Ports> {
+
+        override val tag: PluginTag = PluginTag("controls.ports", group = PluginTag.DATAFORGE_GROUP)
+
+        override val type: KClass<out Ports> = Ports::class
+
+        override fun build(context: Context, meta: Meta): Ports = Ports()
+
+    }
+}

controls-core/src/commonMain/kotlin/space/kscience/controls/ports/SynchronousPort.kt

@@ -8,27 +8,35 @@ import kotlinx.coroutines.sync.withLock
 /**
  * A port handler for synchronous (request-response) communication with a port. Only one request could be active at a time (others are suspended.
  * The handler does not guarantee exclusive access to the port so the user mush ensure that no other controller handles port at the moment.
- *
  */
-public class SynchronousPortHandler(public val port: Port) {
+public class SynchronousPort(public val port: Port, private val mutex: Mutex) : Port by port {
-    private val mutex = Mutex()
-
     /**
      * Send a single message and wait for the flow of respond messages.
      */
-    public suspend fun <R> respond(data: ByteArray, transform: suspend Flow<ByteArray>.() -> R): R {
+    public suspend fun <R> respond(data: ByteArray, transform: suspend Flow<ByteArray>.() -> R): R = mutex.withLock {
-        return mutex.withLock {
         port.send(data)
         transform(port.receiving())
     }
-    }
 }
 
+/**
+ * Provide a synchronous wrapper for a port
+ */
+public fun Port.synchronous(mutex: Mutex = Mutex()): SynchronousPort = SynchronousPort(this, mutex)
+
 /**
  * Send request and read incoming data blocks until the delimiter is encountered
  */
-public suspend fun SynchronousPortHandler.respondWithDelimiter(data: ByteArray, delimiter: ByteArray): ByteArray {
+public suspend fun SynchronousPort.respondWithDelimiter(
-    return respond(data) {
+    data: ByteArray,
+    delimiter: ByteArray,
+): ByteArray = respond(data) {
     withDelimiter(delimiter).first()
-    }
+}
+
+public suspend fun SynchronousPort.respondStringWithDelimiter(
+    data: String,
+    delimiter: String,
+): String = respond(data.encodeToByteArray()) {
+    withStringDelimiter(delimiter).first()
 }

controls-core/src/commonMain/kotlin/space/kscience/controls/ports/phrases.kt

@@ -40,12 +40,11 @@ public fun Flow<ByteArray>.withDelimiter(delimiter: ByteArray): Flow<ByteArray>
 /**
  * Transform byte fragments into utf-8 phrases using utf-8 delimiter
  */
-public fun Flow<ByteArray>.withDelimiter(delimiter: String): Flow<String> {
+public fun Flow<ByteArray>.withStringDelimiter(delimiter: String): Flow<String> {
     return withDelimiter(delimiter.encodeToByteArray()).map { it.decodeToString() }
 }
 
 /**
  * A flow of delimited phrases
  */
-public suspend fun Port.delimitedIncoming(delimiter: ByteArray): Flow<ByteArray> =
+public fun Port.delimitedIncoming(delimiter: ByteArray): Flow<ByteArray> = receiving().withDelimiter(delimiter)
-    receiving().withDelimiter(delimiter)

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DeviceBase.kt

@@ -17,10 +17,17 @@ import kotlin.coroutines.CoroutineContext
 @OptIn(InternalDeviceAPI::class)
 public abstract class DeviceBase<D : DeviceBase<D>>(
     override val context: Context = Global,
-    override val meta: Meta = Meta.EMPTY
+    override val meta: Meta = Meta.EMPTY,
 ) : Device {
 
+    /**
+     * Collection of property specifications
+     */
     public abstract val properties: Map<String, DevicePropertySpec<D, *>>
+
+    /**
+     * Collection of action specifications
+     */
     public abstract val actions: Map<String, DeviceActionSpec<D, *, *>>
 
     override val propertyDescriptors: Collection<PropertyDescriptor>
@@ -33,6 +40,9 @@ public abstract class DeviceBase<D : DeviceBase<D>>(
         context.coroutineContext + SupervisorJob(context.coroutineContext[Job])
     }
 
+    /**
+     * Logical state store
+     */
     private val logicalState: HashMap<String, Meta?> = HashMap()
 
     private val sharedMessageFlow: MutableSharedFlow<DeviceMessage> = MutableSharedFlow()
@@ -99,14 +109,18 @@ public abstract class DeviceBase<D : DeviceBase<D>>(
         actions[action]?.executeWithMeta(self, argument)
 
     /**
-     * Read typed value and update/push event if needed
+     * Read typed value and update/push event if needed.
+     * Return null if property read is not successful or property is undefined.
      */
-    public suspend fun <T> DevicePropertySpec<D, T>.read(): T {
+    public suspend fun <T> DevicePropertySpec<D, T>.readOrNull(): T? {
-        val res = read(self)
+        val res = read(self) ?: return null
         updateLogical(name, converter.objectToMeta(res))
         return res
     }
 
+    public suspend fun <T> DevicePropertySpec<D, T>.read(): T =
+        readOrNull() ?: error("Failed to read property $name state")
+
     public fun <T> DevicePropertySpec<D, T>.get(): T? = getProperty(name)?.let(converter::metaToObject)
 
     /**
@@ -121,6 +135,13 @@ public abstract class DeviceBase<D : DeviceBase<D>>(
         }
     }
 
+    /**
+     * Reset logical state of a property
+     */
+    public suspend fun DevicePropertySpec<D, *>.invalidate() {
+        invalidate(name)
+    }
+
     public suspend operator fun <I, O> DeviceActionSpec<D, I, O>.invoke(input: I? = null): O? = execute(self, input)
 
 }
@@ -132,17 +153,17 @@ public abstract class DeviceBase<D : DeviceBase<D>>(
 public open class DeviceBySpec<D : DeviceBySpec<D>>(
     public val spec: DeviceSpec<in D>,
     context: Context = Global,
-    meta: Meta = Meta.EMPTY
+    meta: Meta = Meta.EMPTY,
 ) : DeviceBase<D>(context, meta) {
     override val properties: Map<String, DevicePropertySpec<D, *>> get() = spec.properties
     override val actions: Map<String, DeviceActionSpec<D, *, *>> get() = spec.actions
 
-    override suspend fun open(): Unit = with(spec){
+    override suspend fun open(): Unit = with(spec) {
         super.open()
         self.onOpen()
     }
 
-    override fun close(): Unit = with(spec){
+    override fun close(): Unit = with(spec) {
         self.onClose()
         super.close()
     }

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DevicePropertySpec.kt

@@ -35,7 +35,7 @@ public interface DevicePropertySpec<in D : Device, T> {
      * Read physical value from the given [device]
      */
     @InternalDeviceAPI
-    public suspend fun read(device: D): T
+    public suspend fun read(device: D): T?
 }
 
 /**
@@ -44,8 +44,8 @@ public interface DevicePropertySpec<in D : Device, T> {
 public val DevicePropertySpec<*, *>.name: String get() = descriptor.name
 
 @OptIn(InternalDeviceAPI::class)
-public suspend fun <D : Device, T> DevicePropertySpec<D, T>.readMeta(device: D): Meta =
+public suspend fun <D : Device, T> DevicePropertySpec<D, T>.readMeta(device: D): Meta? =
-    converter.objectToMeta(read(device))
+    read(device)?.let(converter::objectToMeta)
 
 
 public interface WritableDevicePropertySpec<in D : Device, T> : DevicePropertySpec<D, T> {

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DeviceSpec.kt

@@ -24,25 +24,26 @@ public abstract class DeviceSpec<D : Device> {
     public val actions: Map<String, DeviceActionSpec<D, *, *>> get() = _actions
 
 
-    public open suspend fun D.onOpen(){
+    public open suspend fun D.onOpen() {
     }
 
-    public open fun D.onClose(){
+    public open fun D.onClose() {
     }
 
 
-    public fun <T : Any, P : DevicePropertySpec<D, T>> registerProperty(deviceProperty: P): P {
+    public fun <T, P : DevicePropertySpec<D, T>> registerProperty(deviceProperty: P): P {
         _properties[deviceProperty.name] = deviceProperty
         return deviceProperty
     }
 
-    public fun <T : Any> registerProperty(
+    public fun <T> registerProperty(
         converter: MetaConverter<T>,
         readOnlyProperty: KProperty1<D, T>,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {}
+        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     ): DevicePropertySpec<D, T> {
         val deviceProperty = object : DevicePropertySpec<D, T> {
-            override val descriptor: PropertyDescriptor = PropertyDescriptor(readOnlyProperty.name).apply(descriptorBuilder)
+            override val descriptor: PropertyDescriptor =
+                PropertyDescriptor(readOnlyProperty.name).apply(descriptorBuilder)
             override val converter: MetaConverter<T> = converter
             override suspend fun read(device: D): T =
                 withContext(device.coroutineContext) { readOnlyProperty.get(device) }
@@ -50,11 +51,11 @@ public abstract class DeviceSpec<D : Device> {
         return registerProperty(deviceProperty)
     }
 
-    public fun <T : Any> property(
+    public fun <T> property(
         converter: MetaConverter<T>,
         readOnlyProperty: KProperty1<D, T>,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {}
+        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
-    ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<Any?,DevicePropertySpec<D, T>>> =
+    ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<Any?, DevicePropertySpec<D, T>>> =
         PropertyDelegateProvider { _, property ->
             val deviceProperty = object : DevicePropertySpec<D, T> {
                 override val descriptor: PropertyDescriptor = PropertyDescriptor(property.name).apply {
@@ -74,10 +75,10 @@ public abstract class DeviceSpec<D : Device> {
             }
         }
 
-    public fun <T : Any> mutableProperty(
+    public fun <T> mutableProperty(
         converter: MetaConverter<T>,
         readWriteProperty: KMutableProperty1<D, T>,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {}
+        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<Any?, WritableDevicePropertySpec<D, T>>> =
         PropertyDelegateProvider { _, property ->
             val deviceProperty = object : WritableDevicePropertySpec<D, T> {
@@ -103,11 +104,11 @@ public abstract class DeviceSpec<D : Device> {
             }
         }
 
-    public fun <T : Any> property(
+    public fun <T> property(
         converter: MetaConverter<T>,
         descriptorBuilder: PropertyDescriptor.() -> Unit = {},
         name: String? = null,
-        read: suspend D.() -> T
+        read: suspend D.() -> T?,
     ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, T>>> =
         PropertyDelegateProvider { _: DeviceSpec<D>, property ->
             val propertyName = name ?: property.name
@@ -115,7 +116,7 @@ public abstract class DeviceSpec<D : Device> {
                 override val descriptor: PropertyDescriptor = PropertyDescriptor(propertyName).apply(descriptorBuilder)
                 override val converter: MetaConverter<T> = converter
 
-                override suspend fun read(device: D): T = withContext(device.coroutineContext) { device.read() }
+                override suspend fun read(device: D): T? = withContext(device.coroutineContext) { device.read() }
             }
             registerProperty(deviceProperty)
             ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, T>> { _, _ ->
@@ -123,12 +124,12 @@ public abstract class DeviceSpec<D : Device> {
             }
         }
 
-    public fun <T : Any> mutableProperty(
+    public fun <T> mutableProperty(
         converter: MetaConverter<T>,
         descriptorBuilder: PropertyDescriptor.() -> Unit = {},
         name: String? = null,
-        read: suspend D.() -> T,
+        read: suspend D.() -> T?,
-        write: suspend D.(T) -> Unit
+        write: suspend D.(T) -> Unit,
     ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, WritableDevicePropertySpec<D, T>>> =
         PropertyDelegateProvider { _: DeviceSpec<D>, property: KProperty<*> ->
             val propertyName = name ?: property.name
@@ -136,7 +137,7 @@ public abstract class DeviceSpec<D : Device> {
                 override val descriptor: PropertyDescriptor = PropertyDescriptor(propertyName).apply(descriptorBuilder)
                 override val converter: MetaConverter<T> = converter
 
-                override suspend fun read(device: D): T = withContext(device.coroutineContext) { device.read() }
+                override suspend fun read(device: D): T? = withContext(device.coroutineContext) { device.read() }
 
                 override suspend fun write(device: D, value: T): Unit = withContext(device.coroutineContext) {
                     device.write(value)
@@ -149,17 +150,17 @@ public abstract class DeviceSpec<D : Device> {
         }
 
 
-    public fun <I : Any, O : Any> registerAction(deviceAction: DeviceActionSpec<D, I, O>): DeviceActionSpec<D, I, O> {
+    public fun <I, O> registerAction(deviceAction: DeviceActionSpec<D, I, O>): DeviceActionSpec<D, I, O> {
         _actions[deviceAction.name] = deviceAction
         return deviceAction
     }
 
-    public fun <I : Any, O : Any> action(
+    public fun <I, O> action(
         inputConverter: MetaConverter<I>,
         outputConverter: MetaConverter<O>,
         descriptorBuilder: ActionDescriptor.() -> Unit = {},
         name: String? = null,
-        execute: suspend D.(I?) -> O?
+        execute: suspend D.(I?) -> O?,
     ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DeviceActionSpec<D, I, O>>> =
         PropertyDelegateProvider { _: DeviceSpec<D>, property ->
             val actionName = name ?: property.name
@@ -185,13 +186,14 @@ public abstract class DeviceSpec<D : Device> {
     public fun metaAction(
         descriptorBuilder: ActionDescriptor.() -> Unit = {},
         name: String? = null,
-        execute: suspend D.(Meta?) -> Meta?
+        execute: suspend D.(Meta?) -> Meta?,
-    ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DeviceActionSpec<D, Meta, Meta>>> = action(
+    ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DeviceActionSpec<D, Meta, Meta>>> =
+        action(
             MetaConverter.Companion.meta,
             MetaConverter.Companion.meta,
             descriptorBuilder,
             name
-    ){
+        ) {
             execute(it)
         }
 
@@ -201,14 +203,47 @@ public abstract class DeviceSpec<D : Device> {
     public fun unitAction(
         descriptorBuilder: ActionDescriptor.() -> Unit = {},
         name: String? = null,
-        execute: suspend D.() -> Unit
+        execute: suspend D.() -> Unit,
-    ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DeviceActionSpec<D, Meta, Meta>>> = action(
+    ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DeviceActionSpec<D, Meta, Meta>>> =
+        action(
             MetaConverter.Companion.meta,
             MetaConverter.Companion.meta,
             descriptorBuilder,
             name
-    ){
+        ) {
             execute()
             null
         }
 }
+
+
+/**
+ * Register a mutable logical property for a device
+ */
+@OptIn(InternalDeviceAPI::class)
+public fun <T, D : DeviceBase<D>> DeviceSpec<D>.logicalProperty(
+    converter: MetaConverter<T>,
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    name: String? = null,
+): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<Any?, WritableDevicePropertySpec<D, T>>> =
+    PropertyDelegateProvider { _, property ->
+        val deviceProperty = object : WritableDevicePropertySpec<D, T> {
+            val propertyName = name ?: property.name
+            override val descriptor: PropertyDescriptor = PropertyDescriptor(propertyName).apply {
+                //TODO add type from converter
+                writable = true
+            }.apply(descriptorBuilder)
+
+            override val converter: MetaConverter<T> = converter
+
+            override suspend fun read(device: D): T? =
+                device.getProperty(propertyName)?.let(converter::metaToObject)
+
+            override suspend fun write(device: D, value: T): Unit =
+                device.writeProperty(propertyName, converter.objectToMeta(value))
+        }
+        registerProperty(deviceProperty)
+        ReadOnlyProperty { _, _ ->
+            deviceProperty
+        }
+    }

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/propertySpecDelegates.kt

@@ -13,7 +13,7 @@ import kotlin.properties.ReadOnlyProperty
 public fun <D : DeviceBase<D>> DeviceSpec<D>.booleanProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     name: String? = null,
-    read: suspend D.() -> Boolean
+    read: suspend D.() -> Boolean?
 ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, Boolean>>> = property(
     MetaConverter.boolean,
     {
@@ -38,7 +38,7 @@ private inline fun numberDescriptor(
 public fun <D : DeviceBase<D>> DeviceSpec<D>.numberProperty(
     name: String? = null,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
-    read: suspend D.() -> Number
+    read: suspend D.() -> Number?
 ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, Number>>> = property(
     MetaConverter.number,
     numberDescriptor(descriptorBuilder),
@@ -49,7 +49,7 @@ public fun <D : DeviceBase<D>> DeviceSpec<D>.numberProperty(
 public fun <D : DeviceBase<D>> DeviceSpec<D>.doubleProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     name: String? = null,
-    read: suspend D.() -> Double
+    read: suspend D.() -> Double?
 ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, Double>>> = property(
     MetaConverter.double,
     numberDescriptor(descriptorBuilder),
@@ -60,7 +60,7 @@ public fun <D : DeviceBase<D>> DeviceSpec<D>.doubleProperty(
 public fun <D : DeviceBase<D>> DeviceSpec<D>.stringProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     name: String? = null,
-    read: suspend D.() -> String
+    read: suspend D.() -> String?
 ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, String>>> = property(
     MetaConverter.string,
     {
@@ -76,7 +76,7 @@ public fun <D : DeviceBase<D>> DeviceSpec<D>.stringProperty(
 public fun <D : DeviceBase<D>> DeviceSpec<D>.metaProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     name: String? = null,
-    read: suspend D.() -> Meta
+    read: suspend D.() -> Meta?
 ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, DevicePropertySpec<D, Meta>>> = property(
     MetaConverter.meta,
     {
@@ -94,7 +94,7 @@ public fun <D : DeviceBase<D>> DeviceSpec<D>.metaProperty(
 public fun <D : DeviceBase<D>> DeviceSpec<D>.booleanProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     name: String? = null,
-    read: suspend D.() -> Boolean,
+    read: suspend D.() -> Boolean?,
     write: suspend D.(Boolean) -> Unit
 ): PropertyDelegateProvider<DeviceSpec<D>, ReadOnlyProperty<DeviceSpec<D>, WritableDevicePropertySpec<D, Boolean>>> =
     mutableProperty(

controls-core/src/jvmMain/kotlin/space/kscience/controls/ports/TcpPort.kt

@@ -52,20 +52,20 @@ public class TcpPort private constructor(
                 }
                 if (num < 0) cancel("The input channel is exhausted")
             } catch (ex: Exception) {
-                logger.error(ex){"Channel read error"}
+                logger.error(ex) { "Channel read error" }
                 delay(1000)
             }
         }
     }
 
-    override suspend fun write(data: ByteArray) {
+    override suspend fun write(data: ByteArray): Unit = withContext(Dispatchers.IO){
         futureChannel.await().write(ByteBuffer.wrap(data))
     }
 
     @OptIn(ExperimentalCoroutinesApi::class)
     override fun close() {
         listenerJob.cancel()
-        if(futureChannel.isCompleted){
+        if (futureChannel.isCompleted) {
             futureChannel.getCompleted().close()
         } else {
             futureChannel.cancel()
@@ -74,6 +74,9 @@ public class TcpPort private constructor(
     }
 
     public companion object : PortFactory {
+
+        override val type: String = "tcp"
+
         public fun open(
             context: Context,
             host: String,

controls-core/src/jvmMain/kotlin/space/kscience/controls/ports/TcpPortPlugin.kt

@@ -0,0 +1,30 @@
+package space.kscience.controls.ports
+
+import space.kscience.dataforge.context.AbstractPlugin
+import space.kscience.dataforge.context.Context
+import space.kscience.dataforge.context.PluginFactory
+import space.kscience.dataforge.context.PluginTag
+import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.names.Name
+import kotlin.reflect.KClass
+
+public class TcpPortPlugin : AbstractPlugin() {
+
+    override val tag: PluginTag get() = Companion.tag
+
+    override fun content(target: String): Map<Name, Any> = when(target){
+        PortFactory.TYPE -> mapOf(Name.EMPTY to TcpPort)
+        else -> emptyMap()
+    }
+
+    public companion object : PluginFactory<TcpPortPlugin> {
+
+        override val tag: PluginTag = PluginTag("controls.ports.tcp", group = PluginTag.DATAFORGE_GROUP)
+
+        override val type: KClass<out TcpPortPlugin> = TcpPortPlugin::class
+
+        override fun build(context: Context, meta: Meta): TcpPortPlugin = TcpPortPlugin()
+
+    }
+
+}

controls-core/src/jvmMain/kotlin/space/kscience/controls/spec/getDeviceProperty.kt

@@ -7,4 +7,4 @@ import kotlinx.coroutines.runBlocking
  */
 public operator fun <D : DeviceBase<D>, T : Any> D.get(
     propertySpec: DevicePropertySpec<D, T>
-): T = runBlocking { read(propertySpec) }
+): T? = runBlocking { read(propertySpec) }

controls-ktor-tcp/build.gradle.kts

@@ -5,6 +5,6 @@ plugins {
 val ktorVersion: String by rootProject.extra
 
 dependencies {
-    api(project(":controls-core"))
+    api(projects.controlsCore)
     api("io.ktor:ktor-network:$ktorVersion")
 }

controls-ktor-tcp/src/main/kotlin/space/kscience/controls/ports/KtorTcpPort.kt

@@ -55,7 +55,10 @@ public class KtorTcpPort internal constructor(
         super.close()
     }
 
-    public companion object: PortFactory {
+    public companion object : PortFactory {
+
+        override val type: String = "tcp"
+
         public fun open(
             context: Context,
             host: String,

controls-ktor-tcp/src/main/kotlin/space/kscience/controls/ports/KtorTcpPortPlugin.kt

@@ -0,0 +1,30 @@
+package space.kscience.controls.ports
+
+import space.kscience.dataforge.context.AbstractPlugin
+import space.kscience.dataforge.context.Context
+import space.kscience.dataforge.context.PluginFactory
+import space.kscience.dataforge.context.PluginTag
+import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.names.Name
+import kotlin.reflect.KClass
+
+public class KtorTcpPortPlugin : AbstractPlugin() {
+
+    override val tag: PluginTag get() = Companion.tag
+
+    override fun content(target: String): Map<Name, Any> = when(target){
+        PortFactory.TYPE -> mapOf(Name.EMPTY to KtorTcpPort)
+        else -> emptyMap()
+    }
+
+    public companion object : PluginFactory<KtorTcpPortPlugin> {
+
+        override val tag: PluginTag = PluginTag("controls.ports.serial", group = PluginTag.DATAFORGE_GROUP)
+
+        override val type: KClass<out KtorTcpPortPlugin> = KtorTcpPortPlugin::class
+
+        override fun build(context: Context, meta: Meta): KtorTcpPortPlugin = KtorTcpPortPlugin()
+
+    }
+
+}

controls-serial/src/main/kotlin/space/kscience/controls/serial/SerialPort.kt

@@ -58,6 +58,9 @@ public class SerialPort private constructor(
 
     public companion object : PortFactory {
 
+        override val type: String = "com"
+
+
         /**
          * Construct ComPort with given parameters
          */

controls-serial/src/main/kotlin/space/kscience/controls/serial/SerialPortPlugin.kt

@@ -0,0 +1,31 @@
+package space.kscience.controls.serial
+
+import space.kscience.controls.ports.PortFactory
+import space.kscience.dataforge.context.AbstractPlugin
+import space.kscience.dataforge.context.Context
+import space.kscience.dataforge.context.PluginFactory
+import space.kscience.dataforge.context.PluginTag
+import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.names.Name
+import kotlin.reflect.KClass
+
+public class SerialPortPlugin : AbstractPlugin() {
+
+    override val tag: PluginTag get() = Companion.tag
+
+    override fun content(target: String): Map<Name, Any> = when(target){
+        PortFactory.TYPE -> mapOf(Name.EMPTY to SerialPort)
+        else -> emptyMap()
+    }
+
+    public companion object : PluginFactory<SerialPortPlugin> {
+
+        override val tag: PluginTag = PluginTag("controls.ports.serial", group = PluginTag.DATAFORGE_GROUP)
+
+        override val type: KClass<out SerialPortPlugin> = SerialPortPlugin::class
+
+        override fun build(context: Context, meta: Meta): SerialPortPlugin = SerialPortPlugin()
+
+    }
+
+}

controls-server/build.gradle.kts

@@ -12,7 +12,7 @@ val ktorVersion: String by rootProject.extra
 
 dependencies {
     implementation(project(":controls-core"))
-    implementation(project(":controls-tcp"))
+    implementation(project(":controls-ktor-tcp"))
     implementation(projects.magix.magixServer)
     implementation("io.ktor:ktor-server-cio:$ktorVersion")
     implementation("io.ktor:ktor-server-websockets:$ktorVersion")

demo/mks-pdr900/build.gradle.kts

@@ -0,0 +1,21 @@
+plugins {
+    id("space.kscience.gradle.jvm")
+    application
+}
+
+//TODO to be moved to a separate project
+//
+//application{
+//    mainClass.set("ru.mipt.npm.devices.pimotionmaster.PiMotionMasterAppKt")
+//}
+
+kotlin{
+    explicitApi = null
+}
+
+val ktorVersion: String by rootProject.extra
+val dataforgeVersion: String by extra
+
+dependencies {
+    implementation(projects.controlsKtorTcp)
+}

demo/mks-pdr900/src/main/kotlin/center/sciprog/devices/mks/MksPdr900Device.kt

@@ -0,0 +1,102 @@
+package center.sciprog.devices.mks
+
+import kotlinx.coroutines.withTimeoutOrNull
+import space.kscience.controls.ports.Ports
+import space.kscience.controls.ports.SynchronousPort
+import space.kscience.controls.ports.respondStringWithDelimiter
+import space.kscience.controls.ports.synchronous
+import space.kscience.controls.spec.*
+import space.kscience.dataforge.context.Context
+import space.kscience.dataforge.context.Factory
+import space.kscience.dataforge.context.request
+import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.meta.get
+import space.kscience.dataforge.meta.int
+import space.kscience.dataforge.meta.transformations.MetaConverter
+
+class MksPdr900Device(context: Context, meta: Meta) : DeviceBySpec<MksPdr900Device>(MksPdr900Device, context, meta) {
+
+    private val portDelegate = lazy {
+        val ports = context.request(Ports)
+        ports.buildPort(meta["port"] ?: error("Port is not defined in device configuration")).synchronous()
+    }
+
+    private val port: SynchronousPort by portDelegate
+
+    private val address by meta.int(253)
+    private val channel by meta.int(5)
+
+    private val responsePattern: Regex by lazy {
+        ("@${address}ACK(.*);FF").toRegex()
+    }
+
+    private suspend fun talk(requestContent: String): String? = withTimeoutOrNull(5000) {
+        val answer = port.respondStringWithDelimiter(String.format("@%s%s;FF", address, requestContent), ";FF")
+        responsePattern.matchEntire(answer)?.groups?.get(1)?.value
+            ?: error("Message $answer does not match $responsePattern")
+    }
+
+    public suspend fun readPowerOn(): Boolean = when (val answer = talk("FP?")) {
+        "ON" -> true
+        "OFF" -> false
+        else -> error("Unknown answer for 'FP?': $answer")
+    }
+
+
+    public suspend fun writePowerOn(powerOnValue: Boolean) {
+        error.invalidate()
+        if (powerOnValue) {
+            val ans = talk("FP!ON")
+            if (ans == "ON") {
+                updateLogical(powerOn, true)
+            } else {
+                updateLogical(error, "Failed to set power state")
+            }
+        } else {
+            val ans = talk("FP!OFF")
+            if (ans == "OFF") {
+                updateLogical(powerOn, false)
+            } else {
+                updateLogical(error, "Failed to set power state")
+            }
+        }
+    }
+
+    public suspend fun readChannelData(): Double? {
+        val answer: String? = talk("PR$channel?")
+        error.invalidate()
+        return if (answer.isNullOrEmpty()) {
+            //            updateState(PortSensor.CONNECTED_STATE, false)
+            updateLogical(error, "No connection")
+            null
+        } else {
+            val res = answer.toDouble()
+            if (res <= 0) {
+                updateLogical(powerOn, false)
+                updateLogical(error, "No power")
+                null
+            } else {
+                res
+            }
+        }
+    }
+
+
+    companion object : DeviceSpec<MksPdr900Device>(), Factory<MksPdr900Device> {
+        override fun build(context: Context, meta: Meta): MksPdr900Device = MksPdr900Device(context, meta)
+
+
+        val powerOn by booleanProperty(read = MksPdr900Device::readPowerOn, write = MksPdr900Device::writePowerOn)
+
+        val value by doubleProperty(read = MksPdr900Device::readChannelData)
+
+        val error by logicalProperty(MetaConverter.string)
+
+
+        override fun MksPdr900Device.onClose() {
+            if (portDelegate.isInitialized()) {
+                port.close()
+            }
+        }
+    }
+}

demo/mks-pdr900/src/main/kotlin/center/sciprog/devices/mks/NullableStringMetaConverter.kt

@@ -0,0 +1,10 @@
+package center.sciprog.devices.mks
+
+import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.meta.string
+import space.kscience.dataforge.meta.transformations.MetaConverter
+
+object NullableStringMetaConverter : MetaConverter<String?> {
+    override fun metaToObject(meta: Meta): String? = meta.string
+    override fun objectToMeta(obj: String?): Meta = Meta {}
+}

demo/motors/build.gradle.kts

@@ -23,7 +23,7 @@ val ktorVersion: String by rootProject.extra
 val dataforgeVersion: String by extra
 
 dependencies {
-    implementation(project(":controls-tcp"))
+    implementation(project(":controls-ktor-tcp"))
     implementation(project(":controls-magix-client"))
     implementation("no.tornado:tornadofx:1.7.20")
 }

demo/motors/src/main/kotlin/ru/mipt/npm/devices/pimotionmaster/PiMotionMasterApp.kt

@@ -44,8 +44,8 @@ fun VBox.piMotionMasterAxis(
     label(axisName)
     coroutineScope.launch {
         with(axis) {
-            val min = minPosition.read()
+            val min: Double = minPosition.read()
-            val max = maxPosition.read()
+            val max: Double = maxPosition.read()
             val positionProperty = fxProperty(position)
             val startPosition = position.read()
             runLater {

demo/motors/src/main/kotlin/ru/mipt/npm/devices/pimotionmaster/PiMotionMasterDevice.kt

@@ -87,7 +87,7 @@ class PiMotionMasterDevice(
     suspend fun getErrorCode(): Int = mutex.withLock {
         withTimeout(timeoutValue) {
             sendCommandInternal("ERR?")
-            val errorString = port?.receiving()?.withDelimiter("\n")?.first() ?: error("Not connected to device")
+            val errorString = port?.receiving()?.withStringDelimiter("\n")?.first() ?: error("Not connected to device")
             errorString.trim().toInt()
         }
     }
@@ -100,7 +100,7 @@ class PiMotionMasterDevice(
         try {
             withTimeout(timeoutValue) {
                 sendCommandInternal(command, *arguments)
-                val phrases = port?.receiving()?.withDelimiter("\n") ?: error("Not connected to device")
+                val phrases = port?.receiving()?.withStringDelimiter("\n") ?: error("Not connected to device")
                 phrases.transformWhile { line ->
                     emit(line)
                     line.endsWith(" \n")

settings.gradle.kts

@@ -42,7 +42,7 @@ dependencyResolutionManagement {
 
 include(
     ":controls-core",
-    ":controls-tcp",
+    ":controls-ktor-tcp",
     ":controls-serial",
     ":controls-server",
     ":controls-opcua",
@@ -64,5 +64,6 @@ include(
     ":demo:magix-demo",
     ":demo:car",
     ":demo:motors",
-    ":demo:echo"
+    ":demo:echo",
+    ":demo:mks-pdr900"
 )