index.ts•2.98 kB
import express from "express";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import { JSONRPCError } from "@modelcontextprotocol/sdk/types.js";
import { getServer } from "./src/mcp-server.js";
const app = express();
app.use(express.json());
// Handle POST requests for client-to-server communication
app.post('/mcp', async (req, res) => {
console.log('POST /mcp request received:', {
bodyType: typeof req.body,
body: JSON.stringify(req.body, null, 2),
headers: req.headers,
rawBody: req.body
});
// Log the raw request before MCP processing
console.log('Raw request body:', req.body);
console.log('Request headers:', req.headers);
// In stateless mode, create a new instance of transport and server for each request
// to ensure complete isolation. A single instance would cause request ID collisions
// when multiple clients connect concurrently.
try {
const server = getServer();
const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({
sessionIdGenerator: undefined,
});
res.on('close', () => {
console.log('Request closed');
transport.close();
server.close();
});
await server.connect(transport);
await transport.handleRequest(req, res, req.body);
} catch (error) {
console.error('Error handling MCP request:', error);
console.error('Error details:', JSON.stringify(error, null, 2));
if (!res.headersSent) {
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: 'Internal server error',
},
id: '',
} satisfies JSONRPCError);
}
}
});
app.get('/mcp', async (req, res) => {
// console.log('Received GET MCP request');
res.writeHead(405).end(JSON.stringify({
jsonrpc: "2.0",
error: {
code: -32000,
message: "Method not allowed."
},
id: ''
}));
});
app.delete('/mcp', async (req, res) => {
// console.log('Received DELETE MCP request');
res.writeHead(405).end(JSON.stringify({
jsonrpc: "2.0",
error: {
code: -32000,
message: "Method not allowed."
},
id: ''
}));
});
// Health check endpoint
app.get('/health', (req, res) => {
res.json({
status: 'ok',
timestamp: new Date().toISOString()
});
});
// Start the server
const PORT = process.env.PORT || 3000;
const server = app.listen(PORT, () => {
// console.log(`A Pattern Language MCP Server running on port ${PORT}`);
});
// Handle graceful shutdown
process.on('SIGINT', () => {
// console.log('\nReceived SIGINT. Shutting down gracefully...');
server.close(() => {
// console.log('Server closed');
process.exit(0);
});
});
process.on('SIGTERM', () => {
// console.log('\nReceived SIGTERM. Shutting down gracefully...');
server.close(() => {
// console.log('Server closed');
process.exit(0);
});
});
export { app, server };