fixup! Implement ExposedThing functionality

Author: JKRhb

lib/src/binding_http/http_server.dart

@@ -103,7 +103,7 @@ final class HttpServer implements ProtocolServer {
       switch (affordanceValue) {
         // TODO: Refactor
         // TODO: Handle values from protocol bindings
-        case Property(:final readOnly, :final writeOnly):
+        case Property(:final readOnly, :final writeOnly, :final observable):
           if (!writeOnly) {
             const operationType = OperationType.readproperty;
             final methodName = operationType.defaultHttpMethod;
@@ -161,7 +161,15 @@ final class HttpServer implements ProtocolServer {
               ),
             );
           }
-        // TODO: Handle observe
+
+          if (observable) {
+            const _ = [
+              OperationType.observeproperty,
+              OperationType.unobserveproperty,
+            ];
+
+            // TODO: Implement some kind of event mechanism (e.g., longpolling)
+          }
         case Action():
           const operationType = OperationType.invokeaction;
           final methodName = operationType.defaultHttpMethod;
@@ -193,8 +201,12 @@ final class HttpServer implements ProtocolServer {
           );
 
         case Event():
-          // TODO: Implement
-          continue;
+          const _ = [
+            OperationType.subscribeevent,
+            OperationType.unsubscribeevent,
+          ];
+
+        // TODO: Implement some kind of event mechanism (e.g., longpolling)
       }
     }
 

lib/src/core/implementation/exposed_thing.dart

@@ -44,6 +44,10 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
   final Map<String, scripting_api.EventSubscriptionHandler>
       _eventUnsubscribeHandlers = {};
 
+  final Map<String, ContentListener> _propertyChangeListeners = {};
+
+  final Map<String, ContentListener> _eventListeners = {};
+
   Property _obtainProperty(String name) {
     final property = thingDescription.properties?[name];
 
@@ -57,6 +61,19 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
     return property;
   }
 
+  Event _obtainEvent(String name) {
+    final event = thingDescription.events?[name];
+
+    if (event == null) {
+      throw ArgumentError(
+        "Event $name does not exist in ExposedThing "
+        "with title ${thingDescription.title}.",
+      );
+    }
+
+    return event;
+  }
+
   void _checkReadableProperty(String name) {
     final property = _obtainProperty(name);
 
@@ -85,9 +102,32 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
   }
 
   @override
-  Future<void> emitPropertyChange(String name) {
-    // TODO(JKRhb): implement emitPropertyChange
-    throw UnimplementedError();
+  Future<void> emitPropertyChange(
+    String name, [
+    String contentType = "application/json",
+  ]) async {
+    final property = _obtainProperty(name);
+
+    final readHandler = _propertyReadHandlers[name];
+
+    // TODO: Does this need to be a ProtocolListenerRegistry?
+    final propertyChangeHandler = _propertyChangeListeners[name];
+
+    // TODO: Do we need to throw an error here?
+    if (readHandler == null || propertyChangeHandler == null) {
+      return;
+    }
+
+    final interactionInput = await readHandler();
+
+    final content = Content.fromInteractionInput(
+      interactionInput,
+      contentType,
+      _servient.contentSerdes,
+      property,
+    );
+
+    propertyChangeHandler(content);
   }
 
   @override
@@ -96,9 +136,27 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
   }
 
   @override
-  Future<void> emitEvent(String name, Object? data) {
-    // TODO(JKRhb): implement emitEvent
-    throw UnimplementedError();
+  Future<void> emitEvent(
+    String name,
+    scripting_api.InteractionInput data, [
+    String contentType = "application/json",
+  ]) async {
+    final event = _obtainEvent(name);
+
+    final eventListener = _eventListeners[name];
+
+    if (eventListener == null) {
+      return;
+    }
+
+    final content = Content.fromInteractionInput(
+      data,
+      contentType,
+      _servient.contentSerdes,
+      event.data,
+    );
+
+    eventListener(content);
   }
 
   @override
@@ -343,7 +401,8 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
 
   @override
   Future<void> handleObserveProperty(
-    String propertyName, {
+    String propertyName,
+    ContentListener contentListener, {
     int? formIndex,
     Map<String, Object>? uriVariables,
     Object? data,
@@ -356,6 +415,8 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
       );
     }
 
+    _propertyChangeListeners[propertyName] = contentListener;
+
     await observeHandler(
       data: data,
       uriVariables: uriVariables,
@@ -387,7 +448,8 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
 
   @override
   Future<void> handleSubscribeEvent(
-    String eventName, {
+    String eventName,
+    ContentListener contentListener, {
     int? formIndex,
     Map<String, Object>? uriVariables,
     Object? data,

lib/src/core/protocol_interfaces/exposable_thing.dart

@@ -10,6 +10,9 @@ import "../implementation.dart";
 ///
 typedef PropertyContentMap = Map<String, Content>;
 
+///
+typedef ContentListener = void Function(Content content);
+
 /// Interface that allows ProtocolServers to interact with ExposedThings.
 // TODO: This needs a better name
 abstract interface class ExposableThing {
@@ -58,7 +61,8 @@ abstract interface class ExposableThing {
 
   /// Handles an `observeproperty` operation triggered by a TD consumer.
   Future<void> handleObserveProperty(
-    String eventName, {
+    String eventName,
+    ContentListener contentListener, {
     int? formIndex,
     Map<String, Object>? uriVariables,
     Object? data,
@@ -83,7 +87,8 @@ abstract interface class ExposableThing {
 
   /// Handles a `subscribeevent` operation triggered by a TD consumer.
   Future<void> handleSubscribeEvent(
-    String eventName, {
+    String eventName,
+    ContentListener contentListener, {
     int? formIndex,
     Map<String, Object>? uriVariables,
     Object? data,

lib/src/core/scripting_api/exposed_thing.dart

@@ -4,6 +4,8 @@
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
+import "package:meta/meta.dart";
+
 import "../definitions.dart";
 import "interaction_input.dart";
 import "interaction_output.dart";
@@ -88,7 +90,11 @@ abstract interface class ExposedThing {
 
   /// Informs all subscribers about the change of the property with the given
   /// [name].
-  Future<void> emitPropertyChange(String name);
+  @experimental
+  Future<void> emitPropertyChange(
+    String name, [
+    String contentType = "application/json",
+  ]);
 
   /// Assigns a [handler] function to an action with a given [name].
   ///
@@ -115,5 +121,10 @@ abstract interface class ExposedThing {
   /// occurred.
   ///
   /// You can provide (optional) input [data] that is emitted with the event.
-  Future<void> emitEvent(String name, InteractionInput data);
+  @experimental
+  Future<void> emitEvent(
+    String name,
+    InteractionInput data, [
+    String contentType = "application/json",
+  ]);
 }