fixup! Implement ExposedThing functionality

Author: JKRhb

example/exposed_thing/http_server.dart

@@ -33,6 +33,21 @@ void main() async {
         ],
       },
     },
+    "actions": {
+      "toggle": {
+        "input": {
+          "type": "boolean",
+        },
+        "output": {
+          "type": "null",
+        },
+        "forms": [
+          {
+            "href": "/toggle",
+          }
+        ],
+      },
+    },
   });
 
   exposedThing
@@ -57,10 +72,21 @@ void main() async {
       }
 
       throw const FormatException();
+    })
+    ..setActionHandler("toggle", (
+      actionInput, {
+      data,
+      formIndex,
+      uriVariables,
+    }) async {
+      print(await actionInput.value());
+
+      return InteractionInput.fromNull();
     });
 
   final thingDescription = await wot
       .requestThingDescription(Uri.parse("http://localhost:3000/test"));
+  print(thingDescription.toJson());
   final consumedThing = await wot.consume(thingDescription);
 
   var value = await (await consumedThing.readProperty("status")).value();
@@ -74,5 +100,12 @@ void main() async {
   value = await (await consumedThing.readProperty("status")).value();
   print(value);
 
+  final actionOutput = await consumedThing.invokeAction(
+    "toggle",
+    input: InteractionInput.fromBoolean(true),
+  );
+
+  print(await actionOutput.value());
+
   await servient.shutdown();
 }

lib/src/binding_http/http_extensions.dart

@@ -0,0 +1,41 @@
+// Copyright 2024 Contributors to the Eclipse Foundation. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+import "../../core.dart";
+
+/// Extension for determining the HTTP method that corresponds with an
+/// [OperationType].
+extension HttpMethodExtension on OperationType {
+  /// Returns the default HTTP method as defined in the [HTTP binding template]
+  /// specification.
+  ///
+  /// If the [OperationType] value has no default method defined, an
+  /// [ArgumentError] will be thrown.
+  ///
+  /// [HTTP binding template]: https://w3c.github.io/wot-binding-templates/bindings/protocols/http/#http-default-vocabulary-terms
+  String get defaultHttpMethod {
+    switch (this) {
+      case OperationType.readproperty:
+        return "GET";
+      case OperationType.writeproperty:
+        return "PUT";
+      case OperationType.invokeaction:
+        return "POST";
+      case OperationType.readallproperties:
+        return "GET";
+      case OperationType.writeallproperties:
+        return "PUT";
+      case OperationType.readmultipleproperties:
+        return "GET";
+      case OperationType.writemultipleproperties:
+        return "PUT";
+      default:
+        throw ArgumentError(
+          "OperationType $this has no default HTTP method defined.",
+        );
+    }
+  }
+}

lib/src/binding_http/http_server.dart

@@ -13,6 +13,7 @@ import "package:shelf_router/shelf_router.dart";
 import "../../core.dart" hide ExposedThing;
 
 import "http_config.dart";
+import "http_extensions.dart";
 
 /// A [ProtocolServer] for the Hypertext Transfer Protocol (HTTP).
 final class HttpServer implements ProtocolServer {
@@ -104,7 +105,9 @@ final class HttpServer implements ProtocolServer {
         // TODO: Handle values from protocol bindings
         case Property(:final readOnly, :final writeOnly):
           if (!writeOnly) {
-            router.get(path, (request) async {
+            const operationType = OperationType.readproperty;
+            final methodName = operationType.defaultHttpMethod;
+            router.add(methodName, path, (request) async {
               final content = await thing.handleReadProperty(affordance.key);
 
               return Response(
@@ -120,14 +123,16 @@ final class HttpServer implements ProtocolServer {
               Form(
                 affordanceUri,
                 op: const [
-                  OperationType.readproperty,
+                  operationType,
                 ],
               ),
             );
           }
 
           if (!readOnly) {
-            router.put(path, (request) async {
+            const operationType = OperationType.writeproperty;
+            final methodName = operationType.defaultHttpMethod;
+            router.add(methodName, path, (request) async {
               if (request is! Request) {
                 throw Exception();
               }
@@ -151,14 +156,16 @@ final class HttpServer implements ProtocolServer {
               Form(
                 affordanceUri,
                 op: const [
-                  OperationType.writeproperty,
+                  operationType,
                 ],
               ),
             );
           }
         // TODO: Handle observe
         case Action():
-          router.post(path, (request) async {
+          const operationType = OperationType.invokeaction;
+          final methodName = operationType.defaultHttpMethod;
+          router.add(methodName, path, (request) async {
             if (request is! Request) {
               throw Exception();
             }
@@ -167,13 +174,24 @@ final class HttpServer implements ProtocolServer {
               request.mimeType ?? "application/json",
               request.read(),
             );
-            await thing.handleWriteProperty(affordance.key, content);
+            final blah =
+                await thing.handleInvokeAction(affordance.key, content);
 
             return Response(
+              body: blah?.body,
               204,
             );
           });
 
+          affordanceValue.forms.add(
+            Form(
+              affordanceUri,
+              op: const [
+                operationType,
+              ],
+            ),
+          );
+
         // TODO: Handle observe
         case Event():
           // TODO: Implement

lib/src/core/implementation/exposed_thing.dart

@@ -30,6 +30,8 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
   final Map<String, scripting_api.PropertyWriteHandler> _propertyWriteHandlers =
       {};
 
+  final Map<String, scripting_api.ActionHandler> _actionHandlers = {};
+
   @override
   Future<void> emitPropertyChange(String name) {
     // TODO(JKRhb): implement emitPropertyChange
@@ -60,7 +62,7 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
 
   @override
   void setActionHandler(String name, scripting_api.ActionHandler handler) {
-    // TODO(JKRhb): implement setActionHandler
+    _actionHandlers[name] = handler;
   }
 
   @override
@@ -180,4 +182,45 @@ class ExposedThing implements scripting_api.ExposedThing, ExposableThing {
       data: data,
     );
   }
+
+  @override
+  Future<Content?> handleInvokeAction(
+    String actionName,
+    Content input, {
+    int? formIndex,
+    Map<String, Object>? uriVariables,
+    Object? data,
+  }) async {
+    final actionHandler = _actionHandlers[actionName];
+
+    if (actionHandler == null) {
+      throw Exception(
+        "Action handler for action $actionName is not defined.",
+      );
+    }
+
+    final action = thingDescription.actions?[actionName];
+
+    final processedInput = InteractionOutput(
+      input,
+      _servient.contentSerdes,
+      // FIXME: Providing a form does not really make sense here.
+      Form(Uri()),
+      action?.input,
+    );
+
+    final actionOutput = await actionHandler(
+      processedInput,
+      formIndex: formIndex,
+      uriVariables: uriVariables,
+      data: data,
+    );
+
+    return Content.fromInteractionInput(
+      actionOutput,
+      "application/json",
+      _servient.contentSerdes,
+      null,
+    );
+  }
 }

lib/src/core/protocol_interfaces/exposable_thing.dart

@@ -29,4 +29,13 @@ abstract interface class ExposableThing {
     Map<String, Object>? uriVariables,
     Object? data,
   });
+
+  /// Handles a `invokeaction` operation triggered by a TD consumer.
+  Future<Content?> handleInvokeAction(
+    String propertyName,
+    Content input, {
+    int? formIndex,
+    Map<String, Object>? uriVariables,
+    Object? data,
+  });
 }