Abstract connection management and add serial port support

WelsonJS.Toolkit/WelsonJS.Launcher/ConnectionManagerBase.cs

@@ -0,0 +1,147 @@
+// ConnectionManagerBase.cs
+// SPDX-License-Identifier: GPL-3.0-or-later
+// SPDX-FileCopyrightText: 2025 Catswords OSS and WelsonJS Contributors
+// https://github.com/gnh1201/welsonjs
+//
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace WelsonJS.Launcher
+{
+    /// <summary>
+    /// Provides a reusable pattern for keeping long-lived connections alive and
+    /// recreating them transparently when the underlying connection becomes invalid.
+    /// </summary>
+    /// <typeparam name="TParameters">A descriptor used to create a unique key for each connection.</typeparam>
+    /// <typeparam name="TConnection">The concrete connection type.</typeparam>
+    public abstract class ConnectionManagerBase<TParameters, TConnection>
+        where TConnection : class
+    {
+        private readonly ConcurrentDictionary<string, TConnection> _pool = new ConcurrentDictionary<string, TConnection>();
+
+        /// <summary>
+        /// Creates a unique cache key for the given connection parameters.
+        /// </summary>
+        protected abstract string CreateKey(TParameters parameters);
+
+        /// <summary>
+        /// Establishes a new connection using the provided parameters.
+        /// </summary>
+        protected abstract Task<TConnection> OpenConnectionAsync(TParameters parameters, CancellationToken token);
+
+        /// <summary>
+        /// Validates whether the existing connection is still usable.
+        /// </summary>
+        protected abstract bool IsConnectionValid(TConnection connection);
+
+        /// <summary>
+        /// Releases the resources associated with a connection instance.
+        /// </summary>
+        protected virtual void CloseConnection(TConnection connection)
+        {
+            if (connection is IDisposable disposable)
+            {
+                disposable.Dispose();
+            }
+        }
+
+        /// <summary>
+        /// Retrieves a cached connection or creates a new one if needed.
+        /// </summary>
+        protected async Task<TConnection> GetOrCreateAsync(TParameters parameters, CancellationToken token)
+        {
+            string key = CreateKey(parameters);
+
+            if (_pool.TryGetValue(key, out var existing) && IsConnectionValid(existing))
+            {
+                return existing;
+            }
+
+            RemoveInternal(key, existing);
+
+            var connection = await OpenConnectionAsync(parameters, token).ConfigureAwait(false);
+            _pool[key] = connection;
+            return connection;
+        }
+
+        /// <summary>
+        /// Removes the connection associated with the provided parameters.
+        /// </summary>
+        public void Remove(TParameters parameters)
+        {
+            string key = CreateKey(parameters);
+            if (_pool.TryRemove(key, out var connection))
+            {
+                CloseSafely(connection);
+            }
+        }
+
+        /// <summary>
+        /// Executes an action against the managed connection, retrying once if the first attempt fails.
+        /// </summary>
+        protected async Task<TResult> ExecuteWithRetryAsync<TResult>(
+            TParameters parameters,
+            Func<TConnection, CancellationToken, Task<TResult>> operation,
+            int maxAttempts,
+            CancellationToken token)
+        {
+            if (operation == null) throw new ArgumentNullException(nameof(operation));
+            if (maxAttempts < 1) throw new ArgumentOutOfRangeException(nameof(maxAttempts));
+
+            Exception lastError = null;
+
+            for (int attempt = 0; attempt < maxAttempts; attempt++)
+            {
+                token.ThrowIfCancellationRequested();
+                var connection = await GetOrCreateAsync(parameters, token).ConfigureAwait(false);
+
+                try
+                {
+                    return await operation(connection, token).ConfigureAwait(false);
+                }
+                catch (OperationCanceledException)
+                {
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    lastError = ex;
+                    Remove(parameters);
+                    if (attempt == maxAttempts - 1)
+                    {
+                        throw;
+                    }
+                }
+            }
+
+            throw lastError ?? new InvalidOperationException("Unreachable state in ExecuteWithRetryAsync");
+        }
+
+        private void RemoveInternal(string key, TConnection connection)
+        {
+            if (!string.IsNullOrEmpty(key))
+            {
+                _pool.TryRemove(key, out _);
+            }
+
+            if (connection != null)
+            {
+                CloseSafely(connection);
+            }
+        }
+
+        private void CloseSafely(TConnection connection)
+        {
+            try
+            {
+                CloseConnection(connection);
+            }
+            catch
+            {
+                // Ignore dispose exceptions.
+            }
+        }
+    }
+}

WelsonJS.Toolkit/WelsonJS.Launcher/SerialPortManager.cs

@@ -0,0 +1,183 @@
+// SerialPortManager.cs
+// SPDX-License-Identifier: GPL-3.0-or-later
+// SPDX-FileCopyrightText: 2025 Catswords OSS and WelsonJS Contributors
+// https://github.com/gnh1201/welsonjs
+//
+using System;
+using System.IO;
+using System.IO.Ports;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace WelsonJS.Launcher
+{
+    public sealed class SerialPortManager : ConnectionManagerBase<SerialPortManager.ConnectionParameters, SerialPort>
+    {
+        public struct ConnectionParameters
+        {
+            public ConnectionParameters(
+                string portName,
+                int baudRate,
+                Parity parity = Parity.None,
+                int dataBits = 8,
+                StopBits stopBits = StopBits.One,
+                Handshake handshake = Handshake.None,
+                int readTimeout = 500,
+                int writeTimeout = 500,
+                int readBufferSize = 1024)
+            {
+                if (string.IsNullOrWhiteSpace(portName)) throw new ArgumentNullException(nameof(portName));
+
+                PortName = portName;
+                BaudRate = baudRate;
+                Parity = parity;
+                DataBits = dataBits;
+                StopBits = stopBits;
+                Handshake = handshake;
+                ReadTimeout = readTimeout;
+                WriteTimeout = writeTimeout;
+                ReadBufferSize = readBufferSize > 0 ? readBufferSize : 1024;
+            }
+
+            public string PortName { get; }
+            public int BaudRate { get; }
+            public Parity Parity { get; }
+            public int DataBits { get; }
+            public StopBits StopBits { get; }
+            public Handshake Handshake { get; }
+            public int ReadTimeout { get; }
+            public int WriteTimeout { get; }
+            public int ReadBufferSize { get; }
+        }
+
+        protected override string CreateKey(ConnectionParameters parameters)
+        {
+            return string.Join(",", new object[]
+            {
+                parameters.PortName.ToUpperInvariant(),
+                parameters.BaudRate,
+                parameters.Parity,
+                parameters.DataBits,
+                parameters.StopBits,
+                parameters.Handshake
+            });
+        }
+
+        protected override Task<SerialPort> OpenConnectionAsync(ConnectionParameters parameters, CancellationToken token)
+        {
+            token.ThrowIfCancellationRequested();
+
+            var port = new SerialPort(parameters.PortName, parameters.BaudRate, parameters.Parity, parameters.DataBits, parameters.StopBits)
+            {
+                Handshake = parameters.Handshake,
+                ReadTimeout = parameters.ReadTimeout,
+                WriteTimeout = parameters.WriteTimeout
+            };
+
+            try
+            {
+                port.Open();
+                return Task.FromResult(port);
+            }
+            catch
+            {
+                port.Dispose();
+                throw;
+            }
+        }
+
+        protected override bool IsConnectionValid(SerialPort connection)
+        {
+            return connection != null && connection.IsOpen;
+        }
+
+        protected override void CloseConnection(SerialPort connection)
+        {
+            try
+            {
+                if (connection != null && connection.IsOpen)
+                {
+                    connection.Close();
+                }
+            }
+            finally
+            {
+                connection?.Dispose();
+            }
+        }
+
+        public Task<TResult> ExecuteAsync<TResult>(
+            ConnectionParameters parameters,
+            Func<SerialPort, CancellationToken, Task<TResult>> operation,
+            int maxAttempts = 2,
+            CancellationToken cancellationToken = default)
+        {
+            if (operation == null) throw new ArgumentNullException(nameof(operation));
+            return ExecuteWithRetryAsync(parameters, operation, maxAttempts, cancellationToken);
+        }
+
+        public async Task<string> SendAndReceiveAsync(
+            ConnectionParameters parameters,
+            string message,
+            Encoding encoding,
+            CancellationToken cancellationToken = default)
+        {
+            if (encoding == null) throw new ArgumentNullException(nameof(encoding));
+            byte[] payload = encoding.GetBytes(message ?? string.Empty);
+
+            return await ExecuteWithRetryAsync(
+                parameters,
+                (port, token) => SendAndReceiveInternalAsync(port, parameters.ReadBufferSize, payload, encoding, token),
+                2,
+                cancellationToken).ConfigureAwait(false);
+        }
+
+        private static async Task<string> SendAndReceiveInternalAsync(
+            SerialPort port,
+            int bufferSize,
+            byte[] payload,
+            Encoding encoding,
+            CancellationToken token)
+        {
+            port.DiscardInBuffer();
+            port.DiscardOutBuffer();
+
+            if (payload.Length > 0)
+            {
+                await Task.Run(() => port.Write(payload, 0, payload.Length), token).ConfigureAwait(false);
+            }
+
+            using (var stream = new MemoryStream())
+            {
+                var buffer = new byte[bufferSize];
+
+                while (true)
+                {
+                    try
+                    {
+                        int read = await Task.Run(() => port.Read(buffer, 0, buffer.Length), token).ConfigureAwait(false);
+                        if (read > 0)
+                        {
+                            stream.Write(buffer, 0, read);
+                            if (read < buffer.Length)
+                            {
+                                break;
+                            }
+                        }
+                        else
+                        {
+                            break;
+                        }
+                    }
+                    catch (TimeoutException)
+                    {
+                        break;
+                    }
+                }
+
+                return encoding.GetString(stream.ToArray());
+            }
+        }
+    }
+}

WelsonJS.Toolkit/WelsonJS.Launcher/WebSocketManager.cs

@@ -4,7 +4,6 @@
 // https://github.com/gnh1201/welsonjs
 // 
 using System;
-using System.Collections.Concurrent;
 using System.Net.WebSockets;
 using System.Security.Cryptography;
 using System.Text;
@@ -13,86 +12,73 @@ using System.Threading.Tasks;
 
 namespace WelsonJS.Launcher
 {
-    public class WebSocketManager
+    public sealed class WebSocketManager : ConnectionManagerBase<WebSocketManager.Endpoint, ClientWebSocket>
     {
-        private class Entry
+        public struct Endpoint
         {
-            public ClientWebSocket Socket;
-            public string Host;
-            public int Port;
-            public string Path;
+            public Endpoint(string host, int port, string path)
+            {
+                Host = host ?? throw new ArgumentNullException(nameof(host));
+                Port = port;
+                Path = path ?? string.Empty;
+            }
+
+            public string Host { get; }
+            public int Port { get; }
+            public string Path { get; }
         }
 
-        private readonly ConcurrentDictionary<string, Entry> _pool = new ConcurrentDictionary<string, Entry>();
-
-        // Create a unique cache key using MD5 hash
-        private string MakeKey(string host, int port, string path)
+        protected override string CreateKey(Endpoint parameters)
         {
-            string raw = host + ":" + port + "/" + path;
+            string raw = parameters.Host + ":" + parameters.Port + "/" + parameters.Path;
             using (var md5 = MD5.Create())
             {
                 byte[] hash = md5.ComputeHash(Encoding.UTF8.GetBytes(raw));
-                return BitConverter.ToString(hash).Replace("-", "").ToLower();
+                return BitConverter.ToString(hash).Replace("-", string.Empty).ToLowerInvariant();
             }
         }
 
-        // Get an open WebSocket or connect a new one
-        public async Task<ClientWebSocket> GetOrCreateAsync(string host, int port, string path)
+        protected override async Task<ClientWebSocket> OpenConnectionAsync(Endpoint parameters, CancellationToken token)
         {
-            string key = MakeKey(host, port, path);
-
-            if (_pool.TryGetValue(key, out var entry))
-            {
-                var sock = entry.Socket;
-
-                if (sock == null || sock.State != WebSocketState.Open)
-                {
-                    Remove(host, port, path);
-                }
-                else
-                {
-                    return sock;
-                }
-            }
-
-            var newSock = new ClientWebSocket();
-            var uri = new Uri($"ws://{host}:{port}/{path}");
+            var socket = new ClientWebSocket();
+            var uri = new Uri($"ws://{parameters.Host}:{parameters.Port}/{parameters.Path}");
 
             try
             {
-                await newSock.ConnectAsync(uri, CancellationToken.None);
-
-                _pool[key] = new Entry
-                {
-                    Socket = newSock,
-                    Host = host,
-                    Port = port,
-                    Path = path
-                };
-
-                return newSock;
+                await socket.ConnectAsync(uri, token).ConfigureAwait(false);
+                return socket;
             }
             catch (Exception ex)
             {
-                newSock.Dispose();
-                Remove(host, port, path);
+                socket.Dispose();
                 throw new WebSocketException("WebSocket connection failed", ex);
             }
         }
 
-        // Remove a socket from the pool and dispose it
+        protected override bool IsConnectionValid(ClientWebSocket connection)
+        {
+            return connection != null && connection.State == WebSocketState.Open;
+        }
+
+        protected override void CloseConnection(ClientWebSocket connection)
+        {
+            try
+            {
+                connection?.Abort();
+            }
+            catch
+            {
+                // Ignore abort exceptions.
+            }
+            finally
+            {
+                connection?.Dispose();
+            }
+        }
+
         public void Remove(string host, int port, string path)
         {
-            string key = MakeKey(host, port, path);
-            if (_pool.TryRemove(key, out var entry))
-            {
-                try
-                {
-                    entry.Socket?.Abort();
-                    entry.Socket?.Dispose();
-                }
-                catch { /* Ignore dispose exceptions */ }
-            }
+            Remove(new Endpoint(host, port, path));
         }
 
         // Send and receive with automatic retry on first failure
@@ -103,35 +89,32 @@ namespace WelsonJS.Launcher
                 ? new CancellationTokenSource(TimeSpan.FromSeconds(timeoutSec))
                 : new CancellationTokenSource();
 
-            for (int attempt = 0; attempt < 2; attempt++)
+            try
             {
-                try
-                {
-                    return await TrySendAndReceiveAsync(host, port, path, buf, cts.Token);
-                }
-                catch
-                {
-                    Remove(host, port, path);
-                    if (attempt == 1) throw;
-                }
+                return await ExecuteWithRetryAsync(
+                    new Endpoint(host, port, path),
+                    (socket, token) => TrySendAndReceiveAsync(socket, buf, token),
+                    2,
+                    cts.Token).ConfigureAwait(false);
+            }
+            finally
+            {
+                cts.Dispose();
             }
-
-            throw new InvalidOperationException("Unreachable");
         }
 
         // Actual send and receive implementation that never truncates the accumulated data.
         // - Uses a fixed-size read buffer ONLY for I/O
         // - Accumulates dynamically into a List<byte[]> until EndOfMessage
-        private async Task<string> TrySendAndReceiveAsync(string host, int port, string path, byte[] buf, CancellationToken token)
+        private async Task<string> TrySendAndReceiveAsync(ClientWebSocket socket, byte[] buf, CancellationToken token)
         {
             try
             {
-                var sock = await GetOrCreateAsync(host, port, path);
-                if (sock.State != WebSocketState.Open)
+                if (socket.State != WebSocketState.Open)
                     throw new WebSocketException("WebSocket is not in an open state");
 
                 // Send request as a single text frame
-                await sock.SendAsync(new ArraySegment<byte>(buf), WebSocketMessageType.Text, true, token);
+                await socket.SendAsync(new ArraySegment<byte>(buf), WebSocketMessageType.Text, true, token).ConfigureAwait(false);
 
                 // Fixed-size read buffer for I/O (does NOT cap total message size)
                 byte[] readBuffer = new byte[8192];
@@ -142,12 +125,12 @@ namespace WelsonJS.Launcher
 
                 while (true)
                 {
-                    var res = await sock.ReceiveAsync(new ArraySegment<byte>(readBuffer), token);
+                    var res = await socket.ReceiveAsync(new ArraySegment<byte>(readBuffer), token).ConfigureAwait(false);
 
                     if (res.MessageType == WebSocketMessageType.Close)
                     {
-                        try { await sock.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing as requested by server", token); } catch { }
-                        throw new WebSocketException($"WebSocket closed by server: {sock.CloseStatus} {sock.CloseStatusDescription}");
+                        try { await socket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing as requested by server", token).ConfigureAwait(false); } catch { }
+                        throw new WebSocketException($"WebSocket closed by server: {socket.CloseStatus} {socket.CloseStatusDescription}");
                     }
 
                     if (res.Count > 0)

WelsonJS.Toolkit/WelsonJS.Launcher/WelsonJS.Launcher.csproj

@@ -80,6 +80,7 @@
     <Reference Include="System.Deployment" />
     <Reference Include="System.Drawing" />
     <Reference Include="System.IO.Compression.FileSystem" />
+    <Reference Include="System.IO.Ports" />
     <Reference Include="System.Net.Http" />
     <Reference Include="System.Web" />
     <Reference Include="System.Windows.Forms" />
@@ -87,6 +88,7 @@
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="ConnectionManagerBase.cs" />
     <Compile Include="ICompatibleLogger.cs" />
     <Compile Include="IResourceTool.cs" />
     <Compile Include="JsCore.cs" />
@@ -128,6 +130,7 @@
       <DependentUpon>GlobalSettingsForm.cs</DependentUpon>
     </Compile>
     <Compile Include="ResourceServer.cs" />
+    <Compile Include="SerialPortManager.cs" />
     <Compile Include="TraceLogger.cs" />
     <Compile Include="WebSocketManager.cs" />
     <EmbeddedResource Include="EnvForm.resx">