Countries MCP Server

import cors from "cors"; import express, { Request, Response } from "express"; import dotenv from "dotenv"; import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js"; import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js"; import { isInitializeRequest } from "@modelcontextprotocol/sdk/types.js"; import { randomUUID } from "crypto"; import { setTools } from "./tools"; dotenv.config(); const app = express(); app.use(express.json()); app.use(cors()); const transports: { [sessionId: string]: StreamableHTTPServerTransport } = {}; app.post("/mcp", async (req: Request, res: Response) => { const sessionId = getSessionIdFromHeader(req); let transport: StreamableHTTPServerTransport; if(sessionId && transports[sessionId]) { transport = transports[sessionId]; } else if(!sessionId && isInitializeRequest(req.body)) { const newSessionId = randomUUID(); res.setHeader("mcp-session-id", newSessionId); transport = new StreamableHTTPServerTransport({ sessionIdGenerator: () => newSessionId, onsessioninitialized: (sessionId) => { transports[sessionId] = transport; }, }); transport.onclose = () => { if (transport.sessionId) { delete transports[transport.sessionId]; } } const server = new McpServer({ name: "Demo", version: "1.0.0" }); setTools(server) await server.connect(transport); } else { res.status(400).json({ jsonrpc: '2.0', error: { code: -32000, message: 'Bad Request: No valid session ID provided', }, id: null }); return; } await transport.handleRequest(req, res, req.body) }); const handleSessionRequest = async (req: Request, res: Response) => { const sessionId = getSessionIdFromHeader(req); if(!sessionId || !transports[sessionId]){ res.status(400).send('Invalid or missing session ID'); return; } const transport = transports[sessionId]; await transport.handleRequest(req, res); } const getSessionIdFromHeader = (req: Request) => { return req.headers['mcp-session-id'] as string | undefined; } app.get('/mcp', handleSessionRequest) app.delete('/mcp', handleSessionRequest) app.listen(process.env.PORT || 3000)