feat!: add supportsOperation methods across codebase

Author: JKRhb

lib/src/binding_coap/coap_client_factory.dart

@@ -8,6 +8,7 @@ import "../../core.dart";
 
 import "coap_client.dart";
 import "coap_config.dart";
+import "coap_definitions.dart";
 
 /// A [ProtocolClientFactory] that produces CoAP clients.
 final class CoapClientFactory implements ProtocolClientFactory {
@@ -45,4 +46,21 @@ final class CoapClientFactory implements ProtocolClientFactory {
   bool init() {
     return true;
   }
+
+  @override
+  bool supportsOperation(OperationType operationType, String? subprotocol) {
+    const observeOperations = [
+      OperationType.observeproperty,
+      OperationType.unobserveproperty,
+      OperationType.subscribeevent,
+      OperationType.unsubscribeevent,
+    ];
+
+    if (observeOperations.contains(operationType)) {
+      return CoapSubprotocol.tryParse(subprotocol ?? "") ==
+          CoapSubprotocol.observe;
+    }
+
+    return subprotocol == null;
+  }
 }

lib/src/binding_http/http_client_factory.dart

@@ -42,4 +42,24 @@ final class HttpClientFactory implements ProtocolClientFactory {
   bool init() {
     return true;
   }
+
+  @override
+  bool supportsOperation(OperationType operationType, String? subprotocol) {
+    const unsupportedOperations = [
+      OperationType.observeproperty,
+      OperationType.unobserveproperty,
+      OperationType.subscribeevent,
+      OperationType.unsubscribeevent,
+    ];
+
+    if (unsupportedOperations.contains(operationType)) {
+      return false;
+    }
+
+    if (subprotocol != null) {
+      return false;
+    }
+
+    return true;
+  }
 }

lib/src/binding_mqtt/mqtt_client_factory.dart

@@ -42,4 +42,10 @@ final class MqttClientFactory implements ProtocolClientFactory {
 
   @override
   Set<String> get schemes => {mqttUriScheme, mqttSecureUriScheme};
+
+  @override
+  bool supportsOperation(OperationType operationType, String? subprotocol) {
+    // MQTT client does not support any subprotocols
+    return subprotocol == null;
+  }
 }

lib/src/core/implementation/consumed_thing.dart

@@ -97,9 +97,19 @@ class ConsumedThing implements scripting_api.ConsumedThing {
       }
     } else {
       foundForm = augmentedForms.firstWhere(
-        (form) =>
-            hasClientFor(form.href.scheme) &&
-            _supportsOperationType(form, interactionAffordance, operationType),
+        (form) {
+          final opValues = form.op;
+
+          if (!opValues.contains(operationType)) {
+            return false;
+          }
+
+          return servient.supportsOperation(
+            form.resolvedHref.scheme,
+            operationType,
+            form.subprotocol,
+          );
+        },
         // TODO(JKRhb): Add custom Exception
         orElse: () => throw Exception("No matching form found!"),
       );
@@ -429,17 +439,6 @@ class ConsumedThing implements scripting_api.ConsumedThing {
     }
   }
 
-  static bool _supportsOperationType(
-    Form form,
-    InteractionAffordance interactionAffordance,
-    OperationType operationType,
-  ) {
-    final opValues =
-        form.op ?? OperationType.defaultOpValues(interactionAffordance);
-
-    return opValues.contains(operationType);
-  }
-
   /// Cleans up the resources used by this [ConsumedThing].
   void destroy() {
     for (final observedProperty in _observedProperties.values) {

lib/src/core/implementation/protocol_interfaces/protocol_client_factory.dart

@@ -4,6 +4,9 @@
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
+import "package:meta/meta.dart";
+
+import "../../definitions.dart";
 import "protocol_client.dart";
 
 /// Base class for a factory that produces [ProtocolClient]s.
@@ -24,4 +27,9 @@ abstract interface class ProtocolClientFactory {
   /// Creates a new [ProtocolClient] with that supports one or more of the given
   /// [schemes].
   ProtocolClient createClient();
+
+  /// Indicates whether this [ProtocolClientFactory] supports a given
+  /// [operationType] and subprotocol.
+  @experimental
+  bool supportsOperation(OperationType operationType, String? subprotocol);
 }

lib/src/core/implementation/servient.dart

@@ -4,6 +4,8 @@
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
+import "package:meta/meta.dart";
+
 import "../definitions.dart";
 import "../scripting_api.dart" as scripting_api;
 import "consumed_thing.dart";
@@ -222,6 +224,26 @@ class Servient {
     return clientFactory.createClient();
   }
 
+  /// Indicates whether there is a registered [ProtocolClientFactory] supporting
+  /// the given [operationType] and [subprotocol].
+  ///
+  /// Also returns `false` if there is no [ProtocolClientFactory] registered for
+  /// the given [scheme].
+  @experimental
+  bool supportsOperation(
+    String scheme,
+    OperationType operationType,
+    String? subprotocol,
+  ) {
+    final protocolClient = _clientFactories[scheme];
+
+    if (protocolClient == null) {
+      return false;
+    }
+
+    return protocolClient.supportsOperation(operationType, subprotocol);
+  }
+
   /// Requests a [ThingDescription] from a [url].
   Future<ThingDescription> requestThingDescription(Uri url) async {
     final client = clientFor(url.scheme);

test/core/discovery_test.dart

@@ -258,6 +258,10 @@ class _MockedProtocolClientFactory implements ProtocolClientFactory {
 
   @override
   Set<String> get schemes => {testUriScheme};
+
+  @override
+  bool supportsOperation(OperationType operationType, String? subprotocol) =>
+      true;
 }
 
 extension _DiscoveryContentCreationExtension on String {

test/core/servient_test.dart

@@ -27,6 +27,10 @@ class MockedProtocolClientFactory implements ProtocolClientFactory {
 
   @override
   Set<String> get schemes => {testUriScheme};
+
+  @override
+  bool supportsOperation(OperationType operationType, String? subprotocol) =>
+      true;
 }
 
 void main() {