refactor: add possibility to support different URI schemes

lib/src/channel/coap_network_manager.dart

@@ -7,17 +7,40 @@
 
 part of coap;
 
+/// This [Exception] is thrown when an unsupported URI scheme is encountered.
+class UnsupportedProtocolException implements Exception {
+  /// The error message of this [Exception].
+  String get message => 'Unsupported URI scheme $uriScheme encountered.';
+
+  /// The unsupported Uri Scheme that was encountered.
+  final String uriScheme;
+
+  /// Constructor.
+  UnsupportedProtocolException(this.uriScheme);
+}
+
 /// A network management/caching class, allows already
 /// bound endpoints to be reused without instantiating them again.
 class CoapNetworkManagement {
   static final List<CoapINetwork> _networks = <CoapINetwork>[];
 
   /// Gets a new network, otherwise tries to find a cached network
   /// and returns that.
-  static CoapINetwork getNetwork(CoapInternetAddress address, int port,
-      {required String namespace}) {
-    final CoapINetwork network =
-        CoapNetworkUDP(address, port, namespace: namespace);
+  static CoapINetwork getNetwork(
+      CoapInternetAddress address, int port, String scheme,
+      {required String namespace, required DefaultCoapConfig config}) {
+    final CoapINetwork network;
+
+    switch (scheme) {
+      case CoapConstants.uriScheme:
+        {
+          network = CoapNetworkUDP(address, port, namespace: namespace);
+          break;
+        }
+      default:
+        throw UnsupportedProtocolException(scheme);
+    }
+
     if (_networks.contains(network)) {
       return _networks.where((CoapINetwork e) => e == network).toList()[0];
     } else {

lib/src/channel/coap_udp_channel.dart

@@ -10,26 +10,30 @@ part of coap;
 /// Channel via UDP protocol.
 class CoapUDPChannel extends CoapIChannel {
   /// Initialise with a specific address and port
-  CoapUDPChannel(this._address, this._port, {required String namespace}) {
-    _eventBus = CoapEventBus(namespace: namespace);
-    final socket =
-        CoapNetworkManagement.getNetwork(address!, _port, namespace: namespace);
-    _socket = socket as CoapNetworkUDP;
-  }
+  CoapUDPChannel(this._address, this._port, this.uriScheme,
+      {required String namespace, required this.config})
+      : _eventBus = CoapEventBus(namespace: namespace),
+        _socket = CoapNetworkManagement.getNetwork(
+            _address!, _port, CoapConstants.uriScheme,
+            namespace: namespace, config: config);
+
+  final String uriScheme;
 
   final int _port;
 
+  final DefaultCoapConfig config;
+
   @override
   int get port => _port;
   final CoapInternetAddress? _address;
 
   @override
   CoapInternetAddress? get address => _address;
-  late CoapNetworkUDP _socket;
+  final CoapINetwork _socket;
 
   final typed.Uint8Buffer _buff = typed.Uint8Buffer();
 
-  late final CoapEventBus _eventBus;
+  final CoapEventBus _eventBus;
 
   @override
   Future<void> start() async {
@@ -47,9 +51,7 @@ class CoapUDPChannel extends CoapIChannel {
   @override
   Future<void> send(typed.Uint8Buffer data,
       [CoapInternetAddress? address]) async {
-    if (_socket.socket != null) {
-      _socket.send(data, address);
-    }
+    _socket.send(data, address);
   }
 
   @override

lib/src/coap_client.dart

@@ -317,7 +317,8 @@ class CoapClient {
     if (endpoint != null) {
       return endpoint;
     } else {
-      return CoapEndpointManager.getDefaultEndpoint(request.endpoint!,
+      return CoapEndpointManager.getDefaultEndpoint(
+          request.uri.scheme, request.endpoint!,
           namespace: _namespace);
     }
   }
@@ -331,8 +332,10 @@ class CoapClient {
     await request.resolveDestination(addressType);
     // Endpoint and channel
     CoapEndpointManager.getDefaultSpec();
-    final CoapIChannel channel =
-        CoapUDPChannel(request.destination, uri.port, namespace: _namespace);
+
+    final channel = CoapEndpointManager.determineCoapChannel(
+        uri.scheme, request.destination, uri.port,
+        namespace: _namespace, config: _config);
     if (endpoint != null) {
       request.endpoint = endpoint;
     } else {

lib/src/coap_config.dart

@@ -26,7 +26,7 @@ abstract class DefaultCoapConfig {
   int defaultPort = CoapConstants.defaultPort;
 
   /// The default CoAP port for secure CoAP communication (coaps).
-  int get defaultSecurePort => CoapConstants.defaultSecurePort;
+  int defaultSecurePort = CoapConstants.defaultSecurePort;
 
   /// The port which HTTP proxy is on.
   int get httpPort => 8080;

lib/src/net/coap_endpoint.dart

@@ -11,9 +11,8 @@ part of coap;
 class CoapEndPoint implements CoapIEndPoint, CoapIOutbox {
   /// Instantiates a new endpoint with the
   /// specified channel and configuration.
-  CoapEndPoint(CoapIChannel channel, DefaultCoapConfig config,
+  CoapEndPoint(CoapIChannel channel, this._config,
       {required String namespace}) {
-    _config = config;
     _channel = channel;
     _eventBus = CoapEventBus(namespace: namespace);
     _matcher = CoapMatcher(config, namespace: namespace);
@@ -22,19 +21,22 @@ class CoapEndPoint implements CoapIEndPoint, CoapIOutbox {
   }
 
   /// Instantiates a new endpoint with internet address, port and configuration
-  CoapEndPoint.address(
-      CoapInternetAddress localEndpoint, int port, DefaultCoapConfig config,
-      {required String namespace})
-      : this(newUDPChannel(localEndpoint, port, namespace: namespace), config,
+  CoapEndPoint.address(String scheme, CoapInternetAddress localEndpoint,
+      int port, DefaultCoapConfig config, {required String namespace})
+      : this(
+            CoapEndpointManager.determineCoapChannel(
+                scheme, localEndpoint, port,
+                namespace: namespace, config: config),
+            config,
             namespace: namespace);
 
   final CoapILogger? _log = CoapLogManager().logger;
   late final CoapEventBus _eventBus;
 
-  DefaultCoapConfig? _config;
+  DefaultCoapConfig _config;
 
   @override
-  DefaultCoapConfig? get config => _config;
+  DefaultCoapConfig get config => _config;
   late CoapIChannel _channel;
   late CoapStack _coapStack;
   StreamSubscription? subscr;
@@ -104,7 +106,7 @@ class CoapEndPoint implements CoapIEndPoint, CoapIOutbox {
     final data = typed.Uint8Buffer();
     data.addAll(event.data);
     // Return if we have no data, should not happen but be defensive
-    final decoder = config!.spec!.newMessageDecoder(data);
+    final decoder = config.spec!.newMessageDecoder(data);
     if (decoder.isRequest) {
       CoapRequest? request;
       try {
@@ -218,7 +220,7 @@ class CoapEndPoint implements CoapIEndPoint, CoapIOutbox {
   typed.Uint8Buffer _serializeEmpty(CoapEmptyMessage message) {
     var bytes = message.bytes;
     if (bytes == null) {
-      bytes = _config!.spec!.newMessageEncoder().encodeMessage(message);
+      bytes = _config.spec!.newMessageEncoder().encodeMessage(message);
       message.bytes = bytes;
     }
     return bytes!;
@@ -227,7 +229,7 @@ class CoapEndPoint implements CoapIEndPoint, CoapIOutbox {
   typed.Uint8Buffer _serializeRequest(CoapMessage message) {
     var bytes = message.bytes;
     if (bytes == null) {
-      bytes = _config!.spec!.newMessageEncoder().encodeMessage(message);
+      bytes = _config.spec!.newMessageEncoder().encodeMessage(message);
       message.bytes = bytes;
     }
     return bytes!;
@@ -236,17 +238,9 @@ class CoapEndPoint implements CoapIEndPoint, CoapIOutbox {
   typed.Uint8Buffer _serializeResponse(CoapMessage message) {
     var bytes = message.bytes;
     if (bytes == null) {
-      bytes = _config!.spec!.newMessageEncoder().encodeMessage(message);
+      bytes = _config.spec!.newMessageEncoder().encodeMessage(message);
       message.bytes = bytes;
     }
     return bytes!;
   }
-
-  /// New UDP channel
-  static CoapIChannel newUDPChannel(CoapInternetAddress localEndpoint, int port,
-      {required String namespace}) {
-    final CoapIChannel channel =
-        CoapUDPChannel(localEndpoint, port, namespace: namespace);
-    return channel;
-  }
 }

lib/src/net/coap_endpoint_manager.dart

@@ -15,15 +15,40 @@ class CoapEndpointManager {
     config.spec ??= CoapRfc7252();
   }
 
+  static CoapIChannel determineCoapChannel(
+      String uriScheme, CoapInternetAddress? endpoint, int port,
+      {required String namespace, required DefaultCoapConfig config}) {
+    switch (uriScheme) {
+      case CoapConstants.uriScheme:
+        return CoapUDPChannel(endpoint, port, uriScheme,
+            namespace: namespace, config: config);
+      default:
+        throw UnsupportedProtocolException(uriScheme);
+    }
+  }
+
+  static int _getPortForUriScheme(String scheme, CoapISpec spec) {
+    switch (scheme) {
+      case CoapConstants.uriScheme:
+        return spec.defaultPort;
+      case CoapConstants.secureUriScheme:
+        return spec.defaultSecurePort;
+      default:
+        throw UnsupportedProtocolException(scheme);
+    }
+  }
+
   /// Default endpoint
-  static CoapIEndPoint getDefaultEndpoint(CoapIEndPoint endpoint,
+  static CoapIEndPoint getDefaultEndpoint(String scheme, CoapIEndPoint endpoint,
       {required String namespace}) {
     final config = DefaultCoapConfig.inst!;
     config.spec ??= CoapRfc7252();
     config.defaultPort = config.spec!.defaultPort;
-    final CoapIChannel channel = CoapUDPChannel(
-        endpoint.localEndpoint, config.defaultPort,
-        namespace: namespace);
+    config.defaultSecurePort = config.spec!.defaultSecurePort;
+
+    final port = _getPortForUriScheme(scheme, config.spec!);
+    final channel = determineCoapChannel(scheme, endpoint.localEndpoint, port,
+        namespace: namespace, config: config);
     final ep = CoapEndPoint(channel, config, namespace: namespace);
     ep.start();
     return ep;

lib/src/specification/coap_ispec.dart

@@ -15,6 +15,9 @@ abstract class CoapISpec {
   /// Gets the default CoAP port in this draft.
   int get defaultPort;
 
+  /// Gets the default CoAPS port in this draft.
+  int get defaultSecurePort;
+
   /// Encodes a CoAP message into a bytes array.
   /// Returns the encoded bytes, or null if the message can not be encoded,
   /// i.e. the message is not a Request, a Response or an EmptyMessage.

lib/src/specification/rfcs/coap_rfc7252.dart

@@ -44,6 +44,9 @@ class CoapRfc7252 implements CoapISpec {
   @override
   int get defaultPort => 5683;
 
+  @override
+  int get defaultSecurePort => 5684;
+
   @override
   CoapIMessageEncoder newMessageEncoder() => CoapMessageEncoderRfc7252();