feat: add initial NDN binding implementation

Author: JKRhb

lib/binding_ndn.dart

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+// 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
+
+/// Protocol binding for Named Data Networking (NDN). Follows
+/// an experimental [NDN Protocol Binding specification].
+///
+/// [NDN Protocol Binding specification]: https://github.com/JKRhb/wot-binding-templates/tree/ndn-binding
+library binding_ndn;
+
+export "src/binding_ndn/ndn_consumer_factory.dart";

lib/src/binding_ndn/ndn_config.dart

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+// 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 "package:meta/meta.dart";
+
+import "ndn_consumer.dart";
+
+@immutable
+
+/// Configuration class used by [NdnClient]s.
+class NdnConfig {
+  ///
+  const NdnConfig({
+    this.faceUri,
+  });
+
+  /// [Uri] of the local NDN Forwarding Daemon (NFD).
+  ///
+  /// If `null`, then the default [Uri] will be used, connecting the
+  /// [NdnClient] to the NFD via a Unix Socket.
+  final Uri? faceUri;
+}

lib/src/binding_ndn/ndn_consumer.dart

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+// 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 "package:dart_ndn/dart_ndn.dart";
+import "package:meta/meta.dart";
+
+import "../../core.dart";
+import "ndn_config.dart";
+
+/// A WoT [ProtocolClient] acting as an NDN consumer.
+@immutable
+class NdnClient implements ProtocolClient {
+  /// Creates a new [NdnClient] from an NDN [_consumer].
+  const NdnClient(this._consumer);
+
+  /// Asynchronously creates a new [NdnClient] from an [NdnConfig].
+  static Future<NdnClient> create(NdnConfig config) async {
+    final consumer = await Consumer.create(config.faceUri);
+    return NdnClient(consumer);
+  }
+
+  final Consumer _consumer;
+
+  @override
+  Stream<DiscoveryContent> discoverDirectly(
+    Uri uri, {
+    bool disableMulticast = false,
+  }) {
+    // TODO: implement discoverDirectly
+    throw UnimplementedError();
+  }
+
+  @override
+  Stream<DiscoveryContent> discoverWithCoreLinkFormat(Uri uri) {
+    // TODO: implement discoverWithCoreLinkFormat
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<Content> invokeResource(AugmentedForm form, Content content) {
+    // TODO: implement invokeResource
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<Content> readResource(AugmentedForm form) async {
+    // TODO: Add Name.fromUri
+    final name = Name.fromString(form.href.path);
+
+    final result = await _consumer.expressInterest(name);
+
+    switch (result) {
+      case DataReceived(:final data):
+        final iterable = [data.content ?? <int>[]];
+
+        return Content(form.contentType, Stream.fromIterable(iterable));
+      default:
+        throw Exception("TODO");
+    }
+  }
+
+  @override
+  Future<Content> requestThingDescription(Uri url) {
+    // TODO: implement requestThingDescription
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<void> stop() async {
+    await _consumer.shutdown();
+  }
+
+  @override
+  Future<Subscription> subscribeResource(
+    AugmentedForm form, {
+    required void Function(Content content) next,
+    void Function(Exception error)? error,
+    required void Function() complete,
+  }) {
+    // TODO: implement subscribeResource
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<void> writeResource(AugmentedForm form, Content content) {
+    // TODO: implement writeResource
+    throw UnimplementedError();
+  }
+}

lib/src/binding_ndn/ndn_consumer_factory.dart

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+// 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";
+import "ndn_config.dart";
+import "ndn_consumer.dart";
+
+/// A [ProtocolClientFactory] that produces
+class NdnConsumerFactory implements ProtocolClientFactory {
+  NdnConsumerFactory(this.ndnConfig);
+
+  /// The [NdnConfig] acting as the blueprint for creating
+  final NdnConfig ndnConfig;
+
+  @override
+  Future<ProtocolClient> createClient() async {
+    return NdnClient.create(ndnConfig);
+  }
+
+  @override
+  bool destroy() {
+    return true;
+  }
+
+  @override
+  bool init() {
+    return true;
+  }
+
+  @override
+  Set<String> get schemes => {"ndn"};
+
+  @override
+  bool supportsOperation(OperationType operationType, String? subprotocol) {
+    return operationType == OperationType.readproperty && subprotocol == null;
+  }
+}