ExpressJS MCP

/** * Example 07: Configure HTTP Timeout * * This example shows how to configure timeouts for MCP tool invocations. * Useful for: * - Long-running operations * - Preventing hung requests * - Different timeout requirements per tool */ import express, { type Request, type Response } from "express"; import { ExpressMCP } from "../../src/index"; import { app as baseApp } from "../shared/app"; // Create an extended app with slow endpoints const app = express(); app.use(express.json()); // Copy routes from base app app.use(baseApp); // Add endpoints with different response times app.get("/slow/short", async (req: Request, res: Response) => { // 2 second delay await new Promise((resolve) => setTimeout(resolve, 2000)); res.json({ message: "Short delay completed", duration: "2s" }); }); app.get("/slow/medium", async (req: Request, res: Response) => { // 5 second delay await new Promise((resolve) => setTimeout(resolve, 5000)); res.json({ message: "Medium delay completed", duration: "5s" }); }); app.get("/slow/long", async (req: Request, res: Response) => { // 10 second delay await new Promise((resolve) => setTimeout(resolve, 10000)); res.json({ message: "Long delay completed", duration: "10s" }); }); app.get("/slow/very-long", async (req: Request, res: Response) => { // 35 second delay (will timeout with default settings) await new Promise((resolve) => setTimeout(resolve, 35000)); res.json({ message: "Very long delay completed", duration: "35s" }); }); // Create MCP with default timeout (30 seconds) const mcpDefault = new ExpressMCP(app, { mountPath: "/mcp-default", logging: { info: (...args) => console.log("[MCP Default]", ...args), error: (...args) => console.error("[MCP Default ERROR]", ...args), }, }); // Create MCP with short timeout (3 seconds) const mcpShort = new ExpressMCP(app, { mountPath: "/mcp-short", logging: { info: (...args) => console.log("[MCP Short]", ...args), error: (...args) => console.error("[MCP Short ERROR]", ...args), }, }); // Create MCP with long timeout (60 seconds) const mcpLong = new ExpressMCP(app, { mountPath: "/mcp-long", logging: { info: (...args) => console.log("[MCP Long]", ...args), error: (...args) => console.error("[MCP Long ERROR]", ...args), }, }); async function start() { // Initialize all MCP instances await mcpDefault.init(); await mcpShort.init(); await mcpLong.init(); // Mount all MCP instances mcpDefault.mount(); mcpShort.mount(); mcpLong.mount(); // Add custom invoke endpoints with timeout handling app.post("/mcp-short/invoke", async (req: Request, res: Response, next) => { // Override timeout for short MCP req.body.timeout = 3000; next(); }); app.post("/mcp-long/invoke", async (req: Request, res: Response, next) => { // Override timeout for long MCP req.body.timeout = 60000; next(); }); const PORT = process.env.PORT || 3007; app.listen(PORT, () => { console.log(`✅ Express server running on http://localhost:${PORT}`); console.log("\n⏱️ Timeout Configuration:"); console.log(" /mcp-default: 30s timeout (default)"); console.log(" /mcp-short: 3s timeout"); console.log(" /mcp-long: 60s timeout"); console.log("\n🐢 Slow Endpoints:"); console.log(" GET /slow/short - 2s delay"); console.log(" GET /slow/medium - 5s delay"); console.log(" GET /slow/long - 10s delay"); console.log(" GET /slow/very-long - 35s delay"); console.log("\n📝 Test Commands:"); console.log("\n1. Short timeout (will fail on medium/long endpoints):"); console.log(` curl -X POST http://localhost:${PORT}/mcp-short/invoke \\`); console.log(` -H "Content-Type: application/json" \\`); console.log(` -d '{"toolName": "GET_/slow/medium", "args": {}}'`); console.log("\n2. Default timeout (will fail on very-long endpoint):"); console.log( ` curl -X POST http://localhost:${PORT}/mcp-default/invoke \\`, ); console.log(` -H "Content-Type: application/json" \\`); console.log(` -d '{"toolName": "GET_/slow/very-long", "args": {}}'`); console.log("\n3. Long timeout (handles all endpoints):"); console.log(` curl -X POST http://localhost:${PORT}/mcp-long/invoke \\`); console.log(` -H "Content-Type: application/json" \\`); console.log(` -d '{"toolName": "GET_/slow/very-long", "args": {}}'`); console.log("\n4. Per-request timeout override:"); console.log( ` curl -X POST http://localhost:${PORT}/mcp-default/invoke \\`, ); console.log(` -H "Content-Type: application/json" \\`); console.log( ` -d '{"toolName": "GET_/slow/medium", "args": {}, "timeout": 10000}'`, ); }); } start().catch(console.error);