http-server.ts•5.28 kB
import express from 'express';
import cors from 'cors';
import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';
import { logger } from '../utils/logger.js';
import {
CallToolRequestSchema,
ListToolsRequestSchema,
} from '@modelcontextprotocol/sdk/types.js';
export interface HttpServerConfig {
port: number;
host: string;
allowedOrigins: string[];
apiKey?: string;
}
export interface McpServerFactory {
createServer: () => Server;
}
export class HttpTransportServer {
private app: express.Application;
private config: HttpServerConfig;
private serverFactory?: McpServerFactory;
constructor(config: HttpServerConfig) {
this.config = config;
this.app = express();
this.setupMiddleware();
}
private setupMiddleware() {
// CORS configuration
const corsOptions: cors.CorsOptions = {
origin: (origin, callback) => {
// Allow requests with no origin (like mobile apps or curl)
if (!origin) return callback(null, true);
if (this.config.allowedOrigins.includes('*')) {
return callback(null, true);
}
if (this.config.allowedOrigins.includes(origin)) {
return callback(null, true);
}
return callback(new Error('Not allowed by CORS'));
},
credentials: true,
};
this.app.use(cors(corsOptions));
this.app.use(express.json({ limit: '50mb' }));
// Health check endpoint (no auth required)
this.app.get('/health', (req, res) => {
res.json({ status: 'ok', timestamp: new Date().toISOString() });
});
// Info endpoint (no auth required)
this.app.get('/info', (req, res) => {
res.json({
name: 'Excel MCP Server',
version: '1.0.0',
transport: 'SSE',
endpoints: {
sse: '/sse',
health: '/health',
info: '/info',
},
});
});
// API key authentication middleware (applied after public endpoints)
if (this.config.apiKey) {
this.app.use((req, res, next) => {
// Skip auth for health and info endpoints
if (req.path === '/health' || req.path === '/info') {
return next();
}
const apiKey = req.headers['x-api-key'] || req.query.apiKey;
if (apiKey !== this.config.apiKey) {
return res.status(401).json({ error: 'Unauthorized: Invalid API key' });
}
next();
});
}
}
setupMcpEndpoint(serverFactory: McpServerFactory) {
this.serverFactory = serverFactory;
// SSE endpoint for MCP communication
this.app.get('/sse', async (req, res) => {
logger.info('New SSE client connecting...');
try {
// Create a new MCP server instance for this connection
const mcpServer = this.serverFactory!.createServer();
// Create SSE transport with correct endpoint path
// The transport will handle POST requests to this path
const transport = new SSEServerTransport('/messages', res);
// Connect the MCP server to the transport
await mcpServer.connect(transport);
logger.info('SSE connection established and MCP server connected');
// Handle client disconnect
req.on('close', () => {
logger.info('SSE client disconnected');
transport.close().catch((err) => {
logger.error('Error closing transport:', err);
});
});
// Keep connection alive
const keepAlive = setInterval(() => {
if (res.writableEnded) {
clearInterval(keepAlive);
return;
}
res.write(': keep-alive\n\n');
}, 30000);
req.on('close', () => {
clearInterval(keepAlive);
});
} catch (error) {
logger.error('Error in SSE endpoint:', error);
if (!res.headersSent) {
res.status(500).json({ error: 'Failed to establish SSE connection' });
}
}
});
// Message endpoint for client requests
// This endpoint receives POST requests from the client
this.app.post('/messages', async (req, res) => {
try {
logger.info('Received message from client:', JSON.stringify(req.body));
// The SSEServerTransport automatically handles routing of messages
// to the appropriate session. We just need to acknowledge receipt.
// The actual message handling is done by the transport internally.
res.status(200).json({ ok: true });
} catch (error) {
logger.error('Error handling message:', error);
res.status(500).json({ error: 'Internal server error' });
}
});
}
async start(): Promise<void> {
return new Promise((resolve) => {
this.app.listen(this.config.port, this.config.host, () => {
logger.info(`HTTP server listening on http://${this.config.host}:${this.config.port}`);
logger.info(`SSE endpoint: http://${this.config.host}:${this.config.port}/sse`);
logger.info(`Messages endpoint: http://${this.config.host}:${this.config.port}/messages`);
logger.info(`Health check: http://${this.config.host}:${this.config.port}/health`);
resolve();
});
});
}
}