Add JSON-RPC2 stdio & HTTP endpoint support

Introduce JSON-RPC 2.0 handling and a minimal stdio framing server. Adds ApiEndpoints/JsonRpc2 and JsonRpc2Dispatcher to parse and dispatch JSON-RPC requests, and StdioServer to handle Content-Length framed stdio messages. Adds McpToolsList.json (tools list resource) and wires JsonRpc2 into ResourceServer.

Program.cs: add --stdio-jsonrpc2 mode to run the stdio server, and integrate dispatcher usage (with timeout and TODO placeholders for tools/call). ResourceServer: register JsonRpc2 endpoint, change fallback handling to 404 via ServeResource(), and make several resource helper methods static/public for reuse. Update csproj to include new source files and embed the McpToolsList.json resource.

Contains basic implementation and scaffolding; tool-call handling is left as TODO.

WelsonJS.Augmented/WelsonJS.Launcher/ApiEndpoints/JsonRpc2.cs

@@ -0,0 +1,96 @@
+using log4net;
+using System;
+using System.Net;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace WelsonJS.Launcher.ApiEndpoints
+{
+    public class JsonRpc2 : IApiEndpoint
+    {
+        private readonly ResourceServer Server;
+        private readonly HttpClient _httpClient;
+        private readonly ILog _logger;
+        private const string Prefix = "jsonrpc2";
+
+        public JsonRpc2(ResourceServer server, HttpClient httpClient, ILog logger)
+        {
+            Server = server;
+
+            _httpClient = httpClient;
+            _logger = logger;
+        }
+
+        public bool CanHandle(HttpListenerContext context, string path)
+        {
+            if (context == null)
+                return false;
+
+            if (!string.Equals(context.Request.HttpMethod, "POST", StringComparison.OrdinalIgnoreCase))
+                return false;
+
+            if (path.StartsWith(Prefix, StringComparison.OrdinalIgnoreCase) == false)
+                return false;
+
+            string contentType = context.Request.ContentType?.ToLowerInvariant() ?? string.Empty;
+            if (!(contentType.StartsWith("application/json")
+                  || contentType.StartsWith("application/json-rpc")
+                  || contentType.StartsWith("application/jsonrpc")
+                  || contentType.StartsWith("text/json")))
+                return false;
+
+            if (!context.Request.HasEntityBody)
+                return false;
+
+            return true;
+        }
+
+        public async Task HandleAsync(HttpListenerContext context, string path)
+        {
+            string body;
+            try
+            {
+                using (var input = context.Request.InputStream)
+                using (var reader = new System.IO.StreamReader(input, System.Text.Encoding.UTF8))
+                {
+                    body = await reader.ReadToEndAsync();
+                }
+
+                _logger.Debug($"[JsonRpc2] Request body received ({body.Length} bytes)");
+            }
+            catch (Exception ex)
+            {
+                _logger.Error("[JsonRpc2] Failed to read request body", ex);
+
+                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
+                context.Response.Close();
+                return;
+            }
+
+            var dispatcher = new JsonRpc2Dispatcher(_logger);
+
+            using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(300)))
+            {
+                await dispatcher.HandleAsync(
+                    body,
+                    async (method, ser, ct) =>
+                    {
+                        switch (method)
+                        {
+                            case "tools/list":
+                                await Server.ServeResource(context, ResourceServer.GetResource("McpToolsList.json"), "application/json");
+                                break;
+
+                            case "tools/call":
+                                // TODO: implement tool calling
+                                break;
+                        }
+
+                        return string.Empty;
+                    },
+                    cts.Token);
+            }
+        }
+    }
+}

WelsonJS.Augmented/WelsonJS.Launcher/JsonRpc2Dispatcher.cs

@@ -0,0 +1,80 @@
+using log4net;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace WelsonJS.Launcher
+{
+    public sealed class JsonRpc2Request
+    {
+        public string Version;
+        public string Method;
+    }
+
+    public sealed class JsonRpc2Exception : Exception
+    {
+        public JsonRpc2Exception(string message) : base(message) { }
+        public JsonRpc2Exception(string message, Exception inner) : base(message, inner) { }
+    }
+
+    public sealed class JsonRpc2Dispatcher
+    {
+        private readonly ILog _logger;
+
+        public JsonRpc2Dispatcher(ILog logger)
+        {
+            _logger = logger;
+        }
+
+        public async Task<string> HandleAsync(
+            string requestBody,
+            Func<string, JsSerializer, CancellationToken, Task<string>> dispatchMethodAsync,
+            CancellationToken ct)
+        {
+            if (string.IsNullOrEmpty(requestBody))
+                throw new JsonRpc2Exception("Empty request body");
+
+            if (dispatchMethodAsync == null)
+                throw new ArgumentNullException("dispatchMethodAsync");
+
+            using (var ser = new JsSerializer())
+            {
+                int id = ser.Load(requestBody);
+
+                try
+                {
+                    string version = ser.ExtractFrom(id, "jsonrpc");
+                    if (!string.Equals(version, "2.0", StringComparison.Ordinal))
+                        throw new JsonRpc2Exception("Unsupported jsonrpc version: " + version);
+
+                    string method = ser.ExtractFrom(id, "method");
+                    if (string.IsNullOrEmpty(method))
+                        throw new JsonRpc2Exception("Missing method");
+
+                    var req = new JsonRpc2Request
+                    {
+                        Version = version,
+                        Method = method
+                    };
+
+                    return await dispatchMethodAsync(req.Method, ser, ct);
+                }
+                catch (JsonRpc2Exception)
+                {
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    if (_logger != null)
+                        _logger.Error("[JsonRpc2] Parse error", ex);
+
+                    throw new JsonRpc2Exception("Parse error", ex);
+                }
+                finally
+                {
+                    ser.Unload(id);
+                }
+            }
+        }
+    }
+}

WelsonJS.Augmented/WelsonJS.Launcher/McpToolsList.json

@@ -0,0 +1,28 @@
+{
+  "id": 1,
+  "jsonrpc": "2.0",
+  "result": {
+    "tools": [
+      {
+        "name": "run_jsrt_script",
+        "title": "Run JSRT Script",
+        "description": "Execute a JavaScript script on WelsonJS and WSH JSRT (JScript).\n\nOnly ES3-compatible syntax is allowed. ES5 or newer language syntax is not supported.\nA very limited set of ES5 runtime APIs may be available through host-provided compatibility shims, on a best-effort basis and without guarantees.\nDo not rely on strict mode, modern language features, or full polyfill behavior.\nAssume a minimal ES3 execution environment.",
+        "inputSchema": {
+          "type": "object",
+          "properties": {
+            "script": {
+              "type": "string",
+              "description": "JavaScript source code to execute. The script must be written using ES3-compatible syntax and must be suitable for execution in WSH JSRT / WelsonJS."
+            },
+            "timeoutMs": {
+              "type": "integer",
+              "description": "Maximum execution time in milliseconds. If the timeout is exceeded, the script execution may be forcibly terminated by the host.",
+              "minimum": 0
+            }
+          },
+          "required": [ "script" ]
+        }
+      }
+    ]
+  }
+}

WelsonJS.Augmented/WelsonJS.Launcher/Program.cs

@@ -11,9 +11,14 @@ using System.Diagnostics;
 using System.IO;
 using System.IO.Compression;
 using System.Linq;
+using System.Net.Http;
 using System.Reflection;
+using System.Runtime.Remoting.Contexts;
+using System.Text;
 using System.Threading;
+using System.Threading.Tasks;
 using System.Windows.Forms;
+using static System.Windows.Forms.VisualStyles.VisualStyleElement.Tab;
 
 namespace WelsonJS.Launcher
 {
@@ -49,7 +54,8 @@ namespace WelsonJS.Launcher
             string targetFilePath = GetTargetFilePath(args);
             if (!string.IsNullOrEmpty(targetFilePath))
             {
-                try {
+                try
+                {
                     HandleTargetFilePath(targetFilePath);
                 }
                 catch (Exception e)
@@ -59,6 +65,13 @@ namespace WelsonJS.Launcher
                 return;
             }
 
+            // if use stdio JSON-RPC 2.0 mode
+            if (HasArg(args, "--stdio-jsonrpc2"))
+            {
+                RunJsonRpc2StdioServer();
+                return;
+            }
+
             // create the mutex
             _mutex = new Mutex(true, "WelsonJS.Launcher", out bool createdNew);
             if (!createdNew)
@@ -81,6 +94,54 @@ namespace WelsonJS.Launcher
             _mutex.Dispose();
         }
 
+        private static bool HasArg(string[] args, string key)
+        {
+            if (args == null)
+                return false;
+
+            for (int i = 0; i < args.Length; i++)
+                if (string.Equals(args[i], key, StringComparison.OrdinalIgnoreCase))
+                    return true;
+            
+            return false;
+        }
+
+        private static void RunJsonRpc2StdioServer()
+        {
+            var server = new StdioServer(async (payload, ct) =>
+            {
+                var dispatcher = new JsonRpc2Dispatcher(_logger);
+                var body = Encoding.UTF8.GetString(payload);
+
+                using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(300)))
+                {
+                    string result = await dispatcher.HandleAsync(
+                        body,
+                        async (method, ser, _ct) =>
+                        {
+                            switch (method)
+                            {
+                                case "tools/list":
+                                    return Encoding.UTF8.GetString(ResourceServer.GetResource("McpToolList.json"));
+
+                                case "tools/call":
+                                    // TODO: implement tool call handling
+                                    return string.Empty;
+
+                                default:
+                                    return string.Empty;
+                            }
+                        },
+                        cts.Token);
+
+                    // Fix: Convert string result to byte[] before returning
+                    return Encoding.UTF8.GetBytes(result);
+                }
+            });
+
+            server.Run();
+        }
+
         private static void InitializeAssemblyLoader()
         {
             byte[] gzBytes = Properties.Resources.Phantomizer;
@@ -182,7 +243,8 @@ namespace WelsonJS.Launcher
 
         private static string GetTargetFilePath(string[] args)
         {
-            if (args == null || args.Length == 0) return null;
+            if (args == null || args.Length == 0)
+                return null;
 
             for (int i = 0; i < args.Length; i++)
             {

WelsonJS.Augmented/WelsonJS.Launcher/ResourceServer.cs

@@ -4,8 +4,6 @@
 // https://github.com/gnh1201/welsonjs
 // 
 using log4net;
-using log4net.Core;
-using Microsoft.Isam.Esent.Interop;
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -75,6 +73,7 @@ namespace WelsonJS.Launcher
             _apis.Add(new ApiEndpoints.TwoFactorAuth(this, _httpClient, _logger));
             _apis.Add(new ApiEndpoints.Whois(this, _httpClient, _logger));
             _apis.Add(new ApiEndpoints.ImageColorPicker(this, _httpClient, _logger));
+            _apis.Add(new ApiEndpoints.JsonRpc2(this, _httpClient, _logger));
 
             // Register the prefix
             _listener.Prefixes.Add(prefix);
@@ -164,8 +163,8 @@ namespace WelsonJS.Launcher
             // Serve from the blob server
             if (await ServeBlob(context, path)) return;
 
-            // Fallback to serve from a resource name
+            // Fallback to 404 (Not Found)
-            await ServeResource(context, GetResource(_resourceName), "text/html");
+            await ServeResource(context);
         }
 
         private async Task<bool> ServeBlob(HttpListenerContext context, string path, string prefix = null)
@@ -398,7 +397,7 @@ namespace WelsonJS.Launcher
             await ServeResource(context, Encoding.UTF8.GetBytes(data), mimeType, statusCode);
         }
 
-        private byte[] GetResource(string resourceName)
+        public static byte[] GetResource(string resourceName)
         {
             // Try to fetch embedded resource.
             byte[] data = GetEmbeddedResource(typeof(Program).Namespace + "." + resourceName);
@@ -408,7 +407,7 @@ namespace WelsonJS.Launcher
             return GetResourceFromManager(resourceName);
         }
 
-        private byte[] GetEmbeddedResource(string fullResourceName)
+        private static byte[] GetEmbeddedResource(string fullResourceName)
         {
             Assembly assembly = Assembly.GetExecutingAssembly();
             using (Stream stream = assembly.GetManifestResourceStream(fullResourceName))
@@ -425,7 +424,7 @@ namespace WelsonJS.Launcher
             return null;
         }
 
-        private byte[] GetResourceFromManager(string resourceName)
+        private static byte[] GetResourceFromManager(string resourceName)
         {
             object resourceObject = Properties.Resources.ResourceManager.GetObject(resourceName);
             switch (resourceObject)
@@ -439,7 +438,7 @@ namespace WelsonJS.Launcher
             }
         }
 
-        private byte[] ConvertIconToBytes(System.Drawing.Icon icon)
+        private static byte[] ConvertIconToBytes(System.Drawing.Icon icon)
         {
             using (MemoryStream memoryStream = new MemoryStream())
             {

WelsonJS.Augmented/WelsonJS.Launcher/StdioServer.cs

@@ -0,0 +1,209 @@
+// StdioServer.cs
+// Minimal stdio server (Content-Length framing) with delegate-based extension.
+// - Handles ONLY stdio framing (read/write message boundaries)
+// - No JSON parsing/formatting
+// - Sequential processing
+// - Cancellation via Ctrl+C, and EOF handling
+//
+// Delegate contract:
+//   - input: raw UTF-8 payload bytes (exactly Content-Length)
+//   - output: raw UTF-8 payload bytes to write (or null/empty to write nothing)
+//
+// Typical use: plug JSON-RPC/MCP dispatcher outside of this class.
+using System;
+using System.Globalization;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace WelsonJS.Launcher
+{
+    public sealed class StdioServer
+    {
+        public delegate Task<byte[]> Handler(byte[] payload, CancellationToken ct);
+
+        private readonly Stream _inStream;
+        private readonly Stream _outStream;
+        private readonly Handler _handler;
+
+        public StdioServer(Handler handler)
+        {
+            if (handler == null)
+                throw new ArgumentNullException("handler");
+
+            _handler = handler;
+            _inStream = Console.OpenStandardInput();
+            _outStream = Console.OpenStandardOutput();
+        }
+
+        public void Run()
+        {
+            using (var cts = new CancellationTokenSource())
+            {
+                Console.CancelKeyPress += (s, e) =>
+                {
+                    e.Cancel = true;
+                    cts.Cancel();
+                };
+
+                RunAsync(cts.Token).GetAwaiter().GetResult();
+            }
+        }
+
+        public async Task RunAsync(CancellationToken ct)
+        {
+            while (!ct.IsCancellationRequested)
+            {
+                byte[] payload;
+
+                // 1) read one framed message (blocks here waiting for stdin)
+                try
+                {
+                    payload = await ReadOneAsync(ct).ConfigureAwait(false);
+                    if (payload == null) return; // EOF => exit
+                }
+                catch (OperationCanceledException)
+                {
+                    return;
+                }
+                catch
+                {
+                    // framing broken or stream error => stop (or continue if you want resync)
+                    return;
+                }
+
+                // 2) handle + write response (never kill the loop on handler failure)
+                try
+                {
+                    var resp = await _handler(payload, ct).ConfigureAwait(false);
+                    if (resp == null) resp = new byte[0];
+
+                    await WriteOneAsync(resp, ct).ConfigureAwait(false);
+                }
+                catch (OperationCanceledException)
+                {
+                    return;
+                }
+                catch
+                {
+                    // keep listening even if handler fails
+                    // optionally write empty response so client doesn't hang waiting
+                    try { await WriteOneAsync(new byte[0], ct).ConfigureAwait(false); } catch { }
+                    continue;
+                }
+            }
+        }
+
+        private async Task<byte[]> ReadOneAsync(CancellationToken ct)
+        {
+            // Read headers until \r\n\r\n (blocks on stdin)
+            string headers = await ReadHeadersAsync(ct).ConfigureAwait(false);
+            if (headers == null) return null; // EOF
+
+            int contentLength = ParseContentLength(headers);
+            if (contentLength < 0) throw new InvalidDataException("Missing Content-Length");
+
+            return await ReadExactAsync(_inStream, contentLength, ct).ConfigureAwait(false);
+        }
+
+        private async Task WriteOneAsync(byte[] payload, CancellationToken ct)
+        {
+            if (payload == null) payload = new byte[0];
+
+            string header = "Content-Length: " + payload.Length.ToString(CultureInfo.InvariantCulture) + "\r\n\r\n";
+            byte[] headerBytes = Encoding.ASCII.GetBytes(header);
+
+            await _outStream.WriteAsync(headerBytes, 0, headerBytes.Length, ct).ConfigureAwait(false);
+            if (payload.Length > 0)
+                await _outStream.WriteAsync(payload, 0, payload.Length, ct).ConfigureAwait(false);
+
+            await _outStream.FlushAsync(ct).ConfigureAwait(false);
+        }
+
+        private async Task<string> ReadHeadersAsync(CancellationToken ct)
+        {
+            // read byte-by-byte until CRLFCRLF
+            var buf = new byte[4096];
+            int len = 0;
+
+            while (true)
+            {
+                ct.ThrowIfCancellationRequested();
+
+                int b = await ReadByteAsync(_inStream, ct).ConfigureAwait(false);
+                if (b < 0)
+                {
+                    if (len == 0) return null; // clean EOF
+                    throw new EndOfStreamException("EOF while reading headers");
+                }
+
+                if (len == buf.Length)
+                {
+                    // grow
+                    var nb = new byte[buf.Length * 2];
+                    Buffer.BlockCopy(buf, 0, nb, 0, buf.Length);
+                    buf = nb;
+                }
+
+                buf[len++] = (byte)b;
+
+                if (len >= 4 &&
+                    buf[len - 4] == 13 &&
+                    buf[len - 3] == 10 &&
+                    buf[len - 2] == 13 &&
+                    buf[len - 1] == 10)
+                {
+                    return Encoding.ASCII.GetString(buf, 0, len);
+                }
+            }
+        }
+
+        private static int ParseContentLength(string headers)
+        {
+            // minimal parser: Content-Length: N
+            var lines = headers.Split(new[] { "\r\n" }, StringSplitOptions.None);
+            for (int i = 0; i < lines.Length; i++)
+            {
+                var line = lines[i];
+                int colon = line.IndexOf(':');
+                if (colon <= 0) continue;
+
+                var name = line.Substring(0, colon).Trim();
+                if (!name.Equals("Content-Length", StringComparison.OrdinalIgnoreCase)) continue;
+
+                var val = line.Substring(colon + 1).Trim();
+                int n;
+                if (int.TryParse(val, NumberStyles.Integer, CultureInfo.InvariantCulture, out n))
+                    return n;
+            }
+            return -1;
+        }
+
+        private static async Task<byte[]> ReadExactAsync(Stream s, int nBytes, CancellationToken ct)
+        {
+            if (nBytes == 0) return new byte[0];
+
+            var buf = new byte[nBytes];
+            int read = 0;
+
+            while (read < nBytes)
+            {
+                ct.ThrowIfCancellationRequested();
+                int n = await s.ReadAsync(buf, read, nBytes - read, ct).ConfigureAwait(false);
+                if (n <= 0) throw new EndOfStreamException("EOF while reading payload");
+                read += n;
+            }
+
+            return buf;
+        }
+
+        private static async Task<int> ReadByteAsync(Stream s, CancellationToken ct)
+        {
+            var b = new byte[1];
+            int n = await s.ReadAsync(b, 0, 1, ct).ConfigureAwait(false);
+            if (n <= 0) return -1;
+            return b[0];
+        }
+    }
+}

WelsonJS.Augmented/WelsonJS.Launcher/WelsonJS.Launcher.csproj

@@ -91,9 +91,11 @@
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="ApiEndpoints\JsonRpc2.cs" />
     <Compile Include="IApiEndpoint.cs" />
     <Compile Include="JsCore.cs" />
     <Compile Include="JsNative.cs" />
+    <Compile Include="JsonRpc2Dispatcher.cs" />
     <Compile Include="JsSerializer.cs" />
     <Compile Include="ApiEndpoints\ImageColorPicker.cs" />
     <Compile Include="ApiEndpoints\IpQuery.cs" />
@@ -131,6 +133,7 @@
       <DependentUpon>GlobalSettingsForm.cs</DependentUpon>
     </Compile>
     <Compile Include="ResourceServer.cs" />
+    <Compile Include="StdioServer.cs" />
     <Compile Include="WebSocketManager.cs" />
     <EmbeddedResource Include="EnvForm.resx">
       <DependentUpon>EnvForm.cs</DependentUpon>
@@ -153,6 +156,7 @@
     <None Include="log4net.config">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <EmbeddedResource Include="McpToolsList.json" />
     <None Include="packages.config" />
     <None Include="Properties\Settings.settings">
       <Generator>SettingsSingleFileGenerator</Generator>