rpg-mcp

import { WebSocketServer, WebSocket } from 'ws'; import { Transport } from '@modelcontextprotocol/sdk/shared/transport.js'; import { JSONRPCMessage } from '@modelcontextprotocol/sdk/types.js'; export class WebSocketServerTransport implements Transport { private wss: WebSocketServer; private clients: Set<WebSocket> = new Set(); public onclose?: () => void; public onerror?: (error: Error) => void; public onmessage?: (message: JSONRPCMessage) => void; constructor(port: number = 3001) { this.wss = new WebSocketServer({ port }); this.wss.on('connection', (ws) => { console.error(`[WebSocket] Client connected (total: ${this.clients.size + 1})`); this.clients.add(ws); ws.on('message', (data) => { try { const message = JSON.parse(data.toString()) as JSONRPCMessage; this.onmessage?.(message); } catch (e) { this.onerror?.(e as Error); } }); ws.on('close', () => { this.clients.delete(ws); console.error(`[WebSocket] Client disconnected (total: ${this.clients.size})`); }); ws.on('error', (error) => { this.onerror?.(error); }); }); this.wss.on('error', (error) => { this.onerror?.(error); }); console.error(`[WebSocket] Server listening on port ${port}`); } async send(message: JSONRPCMessage): Promise<void> { const data = JSON.stringify(message); const promises: Promise<void>[] = []; for (const client of this.clients) { if (client.readyState === WebSocket.OPEN) { promises.push( new Promise((resolve, reject) => { client.send(data, (error) => { if (error) reject(error); else resolve(); }); }) ); } } await Promise.all(promises); } async start(): Promise<void> { // Server starts in constructor return Promise.resolve(); } async close(): Promise<void> { // Close all client connections for (const client of this.clients) { client.close(); } this.clients.clear(); // Close the WebSocket server return new Promise((resolve, reject) => { this.wss.close((error) => { if (error) reject(error); else { this.onclose?.(); resolve(); } }); }); } // Broadcast to all connected clients (useful for notifications) broadcast(message: JSONRPCMessage): void { const data = JSON.stringify(message); for (const client of this.clients) { if (client.readyState === WebSocket.OPEN) { client.send(data); } } } }