feat(servient): improve handling of client factories

README.md

@@ -47,7 +47,9 @@ import 'package:dart_wot/dart_wot.dart';
 
 Future<void> main(List<String> args) async {
   final CoapClientFactory coapClientFactory = CoapClientFactory();
-  final servient = Servient()..addClientFactory(coapClientFactory);
+  final servient = Servient(
+    protocolClients: [coapClientFactory]
+  );
   final wot = await servient.start();
 
   final thingDescriptionJson = '''

example/coap_discovery.dart

@@ -30,7 +30,7 @@ Future<void> handleThingDescription(
 }
 
 Future<void> main(List<String> args) async {
-  final servient = Servient()..addClientFactory(CoapClientFactory());
+  final servient = Servient(clientFactories: [CoapClientFactory()]);
 
   final wot = await servient.start();
   final uri = Uri.parse('coap://plugfest.thingweb.io:5683/testthing');

example/coap_dns_sd_discovery.dart

@@ -12,7 +12,11 @@ void handleThingDescription(ThingDescription thingDescription) =>
     print('Discovered TD with title "${thingDescription.title}".');
 
 Future<void> main(List<String> args) async {
-  final servient = Servient()..addClientFactory(CoapClientFactory());
+  final servient = Servient(
+    clientFactories: [
+      CoapClientFactory(),
+    ],
+  );
 
   final wot = await servient.start();
   final uri = Uri.parse('_wot._udp.local');

example/coaps_readproperty.dart

@@ -35,7 +35,12 @@ Future<void> main(List<String> args) async {
     ),
     pskCredentialsCallback: _pskCredentialsCallback,
   );
-  final servient = Servient()..addClientFactory(coapClientFactory);
+
+  final servient = Servient(
+    clientFactories: [
+      coapClientFactory,
+    ],
+  );
 
   final wot = await servient.start();
 

example/complex_example.dart

@@ -112,15 +112,19 @@ Future<BasicCredentials?> basicCredentialsCallback(
 }
 
 Future<void> main() async {
-  const coapConfig = CoapConfig(blocksize: 64);
-  final CoapClientFactory coapClientFactory = CoapClientFactory(
-    coapConfig: coapConfig,
+  final coapClientFactory = CoapClientFactory(
+    coapConfig: const CoapConfig(blocksize: 64),
   );
-  final HttpClientFactory httpClientFactory =
+
+  final httpClientFactory =
       HttpClientFactory(basicCredentialsCallback: basicCredentialsCallback);
-  final servient = Servient()
-    ..addClientFactory(coapClientFactory)
-    ..addClientFactory(httpClientFactory);
+
+  final servient = Servient(
+    clientFactories: [
+      coapClientFactory,
+      httpClientFactory,
+    ],
+  );
   final wot = await servient.start();
 
   final thingDescription = ThingDescription(thingDescriptionJson);

example/core_link_format_discovery.dart

@@ -12,7 +12,7 @@ const propertyName = 'status';
 const actionName = 'toggle';
 
 Future<void> main(List<String> args) async {
-  final servient = Servient()..addClientFactory(CoapClientFactory());
+  final servient = Servient(clientFactories: [CoapClientFactory()]);
 
   final wot = await servient.start();
 

example/example.dart

@@ -23,14 +23,19 @@ Future<BasicCredentials?> basicCredentialsCallback(
 }
 
 Future<void> main(List<String> args) async {
-  final CoapClientFactory coapClientFactory = CoapClientFactory();
-  final HttpClientFactory httpClientFactory =
+  final coapClientFactory = CoapClientFactory();
+  final httpClientFactory =
       HttpClientFactory(basicCredentialsCallback: basicCredentialsCallback);
-  final MqttClientFactory mqttClientFactory = MqttClientFactory();
-  final servient = Servient()
-    ..addClientFactory(coapClientFactory)
-    ..addClientFactory(httpClientFactory)
-    ..addClientFactory(mqttClientFactory);
+  final mqttClientFactory = MqttClientFactory();
+
+  final servient = Servient(
+    clientFactories: [
+      coapClientFactory,
+      httpClientFactory,
+      mqttClientFactory,
+    ],
+  );
+
   final wot = await servient.start();
 
   const thingDescriptionJson = '''

example/http_basic_authentication.dart

@@ -68,9 +68,14 @@ Future<BasicCredentials?> basicCredentialsCallback(
 /// Illustrates the usage of both the basic and the automatic security scheme,
 /// with a server supporting basic authentication.
 Future<void> main(List<String> args) async {
-  final HttpClientFactory httpClientFactory =
-      HttpClientFactory(basicCredentialsCallback: basicCredentialsCallback);
-  final servient = Servient()..addClientFactory(httpClientFactory);
+  final httpClientFactory = HttpClientFactory(
+    basicCredentialsCallback: basicCredentialsCallback,
+  );
+  final servient = Servient(
+    clientFactories: [
+      httpClientFactory,
+    ],
+  );
   final wot = await servient.start();
 
   final thingDescription = ThingDescription(thingDescriptionJson);

lib/src/core/servient.dart

@@ -37,13 +37,24 @@ class ServientException implements Exception {
 class Servient {
   /// Creates a new [Servient].
   ///
-  /// A custom [contentSerdes] can be passed that supports other media types
-  /// than the default ones.
+  /// The [Servient] can be preconfigured with a [List] of
+  /// [ProtocolClientFactory]s.
+  /// However, it is also possible to dynamically [addClientFactory]s and
+  /// [removeClientFactory]s at runtime.
+  ///
+  /// If you want to support a custom media type not already included in the
+  /// [ContentSerdes] class, a custom [contentSerdes] object can be passed as an
+  /// argument.
   Servient({
+    List<ProtocolClientFactory>? clientFactories,
     ServerSecurityCallback? serverSecurityCallback,
     ContentSerdes? contentSerdes,
   })  : contentSerdes = contentSerdes ?? ContentSerdes(),
-        _serverSecurityCallback = serverSecurityCallback;
+        _serverSecurityCallback = serverSecurityCallback {
+    for (final clientFactory in clientFactories ?? <ProtocolClientFactory>[]) {
+      addClientFactory(clientFactory);
+    }
+  }
 
   final List<ProtocolServer> _servers = [];
   final Map<String, ProtocolClientFactory> _clientFactories = {};
@@ -184,13 +195,21 @@ class Servient {
   List<String> get clientSchemes =>
       _clientFactories.keys.toList(growable: false);
 
-  /// Adds a new [clientFactory] to this [Servient.]
+  /// Adds a new [clientFactory] to this [Servient].
   void addClientFactory(ProtocolClientFactory clientFactory) {
     for (final scheme in clientFactory.schemes) {
       _clientFactories[scheme] = clientFactory;
     }
   }
 
+  /// Removes a [ProtocolClientFactory] matching the given [scheme] from this
+  /// [Servient], if present.
+  ///
+  /// If a [ProtocolClientFactory] was removed, the method returns it, otherwise
+  /// the return value is `null`.
+  ProtocolClientFactory? removeClientFactory(String scheme) =>
+      _clientFactories.remove(scheme);
+
   /// Checks whether a [ProtocolClient] is avaiable for a given [scheme].
   bool hasClientFor(String scheme) => _clientFactories.containsKey(scheme);
 

test/binding_http/http_test.dart

@@ -128,13 +128,14 @@ void main() {
         ]) async =>
             bearerCredentialsStore[uri.host];
 
-        final servient = Servient()
-          ..addClientFactory(
+        final servient = Servient(
+          clientFactories: [
             HttpClientFactory(
               basicCredentialsCallback: basicCredentialsCallback,
               bearerCredentialsCallback: bearerCredentialsCallback,
             ),
-          );
+          ],
+        );
         final wot = await servient.start();
 
         final consumedThing = await wot.consume(parsedTd);

test/core/consumed_thing_test.dart

@@ -284,7 +284,7 @@ void main() {
 
       final parsedTd = ThingDescription(thingDescriptionJson);
 
-      final servient = Servient()..addClientFactory(HttpClientFactory());
+      final servient = Servient(clientFactories: [HttpClientFactory()]);
       final wot = await servient.start();
 
       final uriVariables = {'value': 'SFRUUEJJTiBpcyBhd2Vzb21l'};

test/core/servient_test.dart

@@ -0,0 +1,61 @@
+// Copyright 2023 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_wot/dart_wot.dart';
+import 'package:test/test.dart';
+
+const testUriScheme = 'test';
+
+class MockedProtocolClientFactory implements ProtocolClientFactory {
+  @override
+  ProtocolClient createClient() {
+    throw UnimplementedError('Instantiating a client is not supported yet.');
+  }
+
+  @override
+  bool destroy() {
+    return true;
+  }
+
+  @override
+  bool init() {
+    return true;
+  }
+
+  @override
+  Set<String> get schemes => {testUriScheme};
+}
+
+void main() {
+  group('Servient Tests', () {
+    test('Should accept a ProtocolClientFactory list as constructor argument',
+        () {
+      final servient = Servient(
+        clientFactories: [
+          MockedProtocolClientFactory(),
+        ],
+      );
+
+      expect(servient.clientSchemes, [testUriScheme]);
+      expect(servient.hasClientFor(testUriScheme), true);
+    });
+
+    test(
+      'Should allow for adding and removing a ProtocolClientFactory at runtime',
+      () {
+        final servient = Servient()
+          ..addClientFactory(MockedProtocolClientFactory());
+
+        expect(servient.hasClientFor(testUriScheme), true);
+
+        servient.removeClientFactory(testUriScheme);
+
+        expect(servient.hasClientFor(testUriScheme), false);
+        expect(servient.clientSchemes.length, 0);
+      },
+    );
+  });
+}