import { randomUUID } from 'node:crypto';
import type { Server as HttpServer } from 'node:http';
import { createMcpExpressApp } from '@modelcontextprotocol/express';
import { NodeStreamableHTTPServerTransport } from '@modelcontextprotocol/node';
import cors from 'cors';
import type { Request, Response } from 'express';
import rateLimit from 'express-rate-limit';
import { createStatelessLearningServer } from './mcpServer.js';
import { methodNotAllowedBody, readAppConfig } from './types.js';
const config = readAppConfig(process.env);
const app = createMcpExpressApp({ host: config.host });
app.use(
cors({
origin: config.corsOrigin === '*' ? true : config.corsOrigin,
methods: ['GET', 'POST', 'DELETE', 'OPTIONS'],
allowedHeaders: ['Content-Type', 'Accept', 'mcp-protocol-version', 'mcp-session-id'],
exposedHeaders: ['mcp-session-id', 'mcp-protocol-version'],
maxAge: 86_400,
}),
);
app.use(
'/mcp',
rateLimit({
windowMs: config.rateLimitWindowMs,
max: config.rateLimitMax,
standardHeaders: true,
legacyHeaders: false,
}),
);
app.get('/health', (_req: Request, res: Response) => {
res.status(200).json({
status: 'ok',
mode: 'http-stateless',
sdkGeneration: 'v2-pre-release',
time: new Date().toISOString(),
});
});
app.post('/mcp', async (req: Request, res: Response) => {
const requestId = randomUUID();
const server = createStatelessLearningServer();
const transport = new NodeStreamableHTTPServerTransport({
sessionIdGenerator: undefined,
});
let closed = false;
const closeAll = async (): Promise<void> => {
if (closed) {
return;
}
closed = true;
await Promise.allSettled([transport.close(), server.close()]);
};
res.on('close', () => {
void closeAll();
});
try {
await server.connect(transport);
await transport.handleRequest(req, res, req.body);
} catch (error) {
await closeAll();
if (!res.headersSent) {
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: 'Internal server error',
},
id: null,
});
}
const message = error instanceof Error ? error.message : String(error);
process.stderr.write(`[${requestId}] Failed to handle /mcp request: ${message}\n`);
}
});
app.get('/mcp', (req: Request, res: Response) => {
res.status(405).json(methodNotAllowedBody(req.method));
});
app.delete('/mcp', (req: Request, res: Response) => {
res.status(405).json(methodNotAllowedBody(req.method));
});
const httpServer: HttpServer = app.listen(config.port, config.host, () => {
process.stdout.write(
`MCP stateless server ready at http://${config.host}:${String(config.port)}/mcp (SDK v2 pre-release)\n`,
);
});
async function shutdown(signal: string): Promise<void> {
process.stdout.write(`Received ${signal}. Shutting down...\n`);
await new Promise<void>((resolve, reject) => {
httpServer.close((error) => {
if (error) {
reject(error);
return;
}
resolve();
});
});
process.stdout.write('Shutdown complete.\n');
}
for (const signal of ['SIGINT', 'SIGTERM']) {
process.on(signal, () => {
void shutdown(signal).catch((error) => {
const message = error instanceof Error ? error.message : String(error);
process.stderr.write(`Graceful shutdown failed: ${message}\n`);
process.exitCode = 1;
});
});
}
