import { createServer, type IncomingMessage, type ServerResponse } from 'node:http';
import { isInitializeRequest } from '@modelcontextprotocol/server';
import type { SessionRegistry } from './session-registry.js';
const sessionIdFromRequest = (req: IncomingMessage): string | undefined => {
const raw = req.headers['mcp-session-id'];
return Array.isArray(raw) ? raw[0] : raw;
};
const readJsonBody = async (req: IncomingMessage): Promise<unknown> => {
const chunks: Buffer[] = [];
for await (const chunk of req) {
chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
}
const text = Buffer.concat(chunks).toString('utf8').trim();
return text.length === 0 ? {} : JSON.parse(text);
};
const sendJson = (res: ServerResponse, statusCode: number, body: unknown): void => {
res.statusCode = statusCode;
res.setHeader('content-type', 'application/json; charset=utf-8');
res.end(JSON.stringify(body));
};
const sendError = (res: ServerResponse, statusCode: number, message: string): void => {
sendJson(res, statusCode, {
jsonrpc: '2.0',
error: {
code: -32000,
message
},
id: null
});
};
export const createHttpServer = (registry: SessionRegistry) => {
return createServer(async (req, res) => {
try {
const url = new URL(req.url ?? '/', 'http://127.0.0.1');
if (url.pathname === '/health') {
sendJson(res, 200, { ok: true, activeSessions: registry.count() });
return;
}
if (url.pathname !== '/mcp') {
sendJson(res, 404, { error: 'Not found' });
return;
}
if (req.method === 'POST') {
const body = await readJsonBody(req);
const sessionId = sessionIdFromRequest(req);
if (sessionId) {
const state = registry.get(sessionId);
if (!state) {
sendError(res, 404, `Session '${sessionId}' not found.`);
return;
}
await state.transport.handleRequest(req, res, body);
return;
}
if (!isInitializeRequest(body)) {
sendError(res, 400, 'Expected initialize request for new session.');
return;
}
const transport = await registry.createTransport();
await transport.handleRequest(req, res, body);
return;
}
if (req.method === 'GET' || req.method === 'DELETE') {
const sessionId = sessionIdFromRequest(req);
if (!sessionId) {
sendError(res, 400, 'Missing mcp-session-id header.');
return;
}
const state = registry.get(sessionId);
if (!state) {
sendError(res, 404, `Session '${sessionId}' not found.`);
return;
}
await state.transport.handleRequest(req, res);
return;
}
res.statusCode = 405;
res.setHeader('allow', 'GET,POST,DELETE');
res.end();
} catch (error) {
console.error(error);
sendError(res, 500, 'Internal server error');
}
});
};
