WIP: Implement CoAP over TCP logic

example/tcp_test.dart

@@ -0,0 +1,47 @@
+// ignore_for_file: avoid_print
+
+import 'dart:core';
+import 'dart:io';
+
+import 'package:coap/coap.dart';
+
+Future<void> startServer() async {
+  final server = await ServerSocket.bind(InternetAddress.anyIPv4, 5683);
+  server.listen((final connection) async {
+    await connection.forEach((final frame) {
+      print(frame);
+
+      const responseCode = (2 << 5) + 5;
+
+      const tokenLength = 8;
+      const tokenOffset = 2;
+      final token = frame.sublist(tokenOffset, tokenOffset + tokenLength);
+
+      final response = [tokenLength, responseCode, ...token];
+
+      connection.add(response);
+    });
+  });
+}
+
+/// Tests the basic functionality of the TCP network.
+/// Will be replaced with a "real" example later.
+Future<void> main() async {
+  await startServer();
+  await connect();
+}
+
+Future<void> connect() async {
+  final coapClient = CoapClient(Uri.parse('coap+tcp://127.0.0.1'));
+
+  final response = await coapClient.get(
+    'test',
+    options: [ContentFormatOption(40)],
+  );
+  // TODO(JKRhb): Responses can't be matched at the moment, as the current
+  //              implementation requires a message ID which is not defined in
+  //              CoAP over TCP.
+  print(response);
+
+  coapClient.close();
+}

lib/src/coap_message.dart

@@ -17,6 +17,7 @@ import 'coap_code.dart';
 import 'coap_media_type.dart';
 import 'coap_message_type.dart';
 import 'coap_response.dart';
+import 'codec/tcp/message_encoder.dart';
 import 'codec/udp/message_decoder.dart';
 import 'codec/udp/message_encoder.dart';
 import 'event/coap_event_bus.dart';
@@ -657,18 +658,8 @@ abstract class CoapMessage {
   /// Is also used for DTLS.
   Uint8Buffer toUdpPayload() => serializeUdpMessage(this);
 
-  /// Serializes this CoAP message from the TCP message format.
-  ///
-  /// Is also used for TLS.
-  static CoapMessage? fromTcpPayload(final Uint8Buffer data) =>
-      throw UnimplementedError(
-        'TCP segment deserialization is not implemented yet.',
-      );
-
   /// Serializes this CoAP message into the TCP message format.
   ///
   /// Is also used for TLS.
-  Uint8Buffer toTcpPayload() => throw UnimplementedError(
-        'TCP segment serialization is not implemented yet.',
-      );
+  Uint8Buffer toTcpPayload() => serializeTcpMessage(this);
 }