/**
* StreamableHTTP Transport for Remote MCP Access
* Modern, robust HTTP transport for MCP servers
*/
import express, { Request, Response } from 'express';
import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
/**
* Creates an Express server with StreamableHTTP transport for remote MCP access.
* This is the modern, recommended transport for production deployments.
*
* @param createMcpServer - Factory function that creates a new MCP server instance
* @param port - Port number to listen on (default: 3000)
* @returns The Express application instance
*/
export function createStreamableServer(createMcpServer: () => Server, port: number = 3000) {
const app = express();
// Enable CORS for cross-origin requests
app.use((req, res, next) => {
res.header('Access-Control-Allow-Origin', '*');
res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization');
if (req.method === 'OPTIONS') {
res.sendStatus(200);
return;
}
next();
});
app.use(express.json());
// Health check endpoint
app.get('/health', (req: Request, res: Response) => {
res.json({
status: 'ok',
service: 'chhart-mcp-server',
version: '1.0.2',
transport: 'streamable-http',
timestamp: new Date().toISOString()
});
});
// Create a single stateless transport instance
// Stateless mode means no session management - each request is independent
const transport = new StreamableHTTPServerTransport({
sessionIdGenerator: undefined, // Stateless mode
});
// Create and connect the MCP server once
const mcpServer = createMcpServer();
mcpServer.connect(transport).catch((error) => {
console.error('Failed to connect MCP server to transport:', error);
process.exit(1);
});
// MCP endpoint for StreamableHTTP communication
app.post('/mcp', async (req: Request, res: Response) => {
console.error('New MCP request received');
try {
// Handle the request using the connected transport
// The transport will parse the request body automatically
await transport.handleRequest(req, res, req.body);
console.error('MCP request completed successfully');
} catch (error) {
console.error('Error handling MCP request:', error);
if (!res.headersSent) {
res.status(500).json({
error: 'Internal server error',
message: error instanceof Error ? error.message : String(error)
});
}
}
});
// Start server
app.listen(port, () => {
console.error(`Chhart MCP Server (StreamableHTTP mode) listening on port ${port}`);
console.error(`Health check: http://localhost:${port}/health`);
console.error(`MCP endpoint: http://localhost:${port}/mcp`);
});
return app;
}
