rpg-mcp

import { Server } from 'net'; import { Transport } from '@modelcontextprotocol/sdk/shared/transport.js'; import { JSONRPCMessage } from '@modelcontextprotocol/sdk/types.js'; /** * A TCP transport for the MCP server. * This implementation uses a simple line-based JSON protocol over TCP. * Note: The official SDK doesn't have a built-in TCP transport yet, so we implement a basic one * that mimics the behavior needed for MCP. * * However, for better compatibility with existing tools, we might want to use SSE or Stdio. * If we strictly need TCP, we need to define the framing. * * For this implementation, we will use a simple newline-delimited JSON format, * similar to how StdioTransport works but over a socket. */ export class TCPServerTransport implements Transport { private server: Server; private socket: any = null; private _onclose?: () => void; private _onerror?: (error: Error) => void; private _onmessage?: (message: JSONRPCMessage) => void; constructor(private port: number = 3000) { this.server = new Server((socket) => { console.log('Client connected'); this.socket = socket; let buffer = ''; socket.on('data', (data) => { buffer += data.toString(); const lines = buffer.split('\n'); buffer = lines.pop() || ''; for (const line of lines) { if (line.trim()) { try { const message = JSON.parse(line); this._onmessage?.(message); } catch (error) { console.error('Failed to parse message:', error); this._onerror?.(error as Error); } } } }); socket.on('error', (err) => { console.error('Socket error:', err); this._onerror?.(err); }); socket.on('close', () => { console.log('Client disconnected'); this._onclose?.(); }); }); } async start(): Promise<void> { return new Promise((resolve) => { this.server.listen(this.port, () => { console.log(`TCP Server listening on port ${this.port}`); resolve(); }); }); } async close(): Promise<void> { return new Promise((resolve, reject) => { this.server.close((err) => { if (err) reject(err); else resolve(); }); }); } async send(message: JSONRPCMessage): Promise<void> { if (!this.socket) { throw new Error('No client connected'); } this.socket.write(JSON.stringify(message) + '\n'); } set onclose(handler: () => void) { this._onclose = handler; } set onerror(handler: (error: Error) => void) { this._onerror = handler; } set onmessage(handler: (message: JSONRPCMessage) => void) { this._onmessage = handler; } }