const http = require('http');
const https = require('https');
const { URL } = require('url');
const EventSource = require('eventsource');
const readline = require('readline');
// Configuration
const MCP_POST_URL = 'http://localhost:8000/messages/';
const MCP_SSE_URL = 'http://localhost:8000/sse/';
const PORT = 3000;
const RECONNECT_DELAY = 5000; // 5 seconds
// Parse URL to determine HTTP or HTTPS
const postUrl = new URL(MCP_POST_URL);
const httpModule = postUrl.protocol === 'https:' ? https : http;
// Set up readline for reading from stdin
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false
});
// Handle incoming messages from Claude Desktop (via stdio)
rl.on('line', (line) => {
try {
const message = JSON.parse(line);
console.error('Received from Claude Desktop:', JSON.stringify(message, null, 2));
// Forward message to MCP server via HTTP POST
const options = {
hostname: postUrl.hostname,
port: postUrl.port || (postUrl.protocol === 'https:' ? 443 : 80),
path: postUrl.pathname,
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Accept': 'text/event-stream',
'Cache-Control': 'no-cache',
'Connection': 'keep-alive',
'Host': postUrl.hostname
}
};
console.error('Sending request to MCP server:', JSON.stringify(options, null, 2));
const req = httpModule.request(options,
(res) => {
let data = '';
res.on('data', (chunk) => {
data += chunk;
// Forward response back to Claude Desktop
process.stdout.write(chunk);
});
res.on('end', () => {
if (res.statusCode !== 200) {
console.error(`HTTP error! Status: ${res.statusCode}`);
console.error('Response:', data);
}
});
}
);
req.on('error', (error) => {
console.error('Error forwarding message to MCP server:', error);
});
req.write(JSON.stringify(message));
req.end();
} catch (error) {
console.error('Error processing message:', error);
}
});
// Function to create a new SSE connection
function createSSEConnection() {
console.error('Creating new SSE connection to:', MCP_SSE_URL);
const es = new EventSource(MCP_SSE_URL, {
headers: {
'Accept': 'text/event-stream',
'Cache-Control': 'no-cache',
'Connection': 'keep-alive'
}
});
es.on('open', () => {
console.error('SSE Connection established');
});
es.on('message', (event) => {
try {
console.error('Received from MCP server:', event.data);
// Forward message to Claude Desktop (via stdout)
process.stdout.write(event.data + '\n');
} catch (error) {
console.error('Error processing SSE message:', error);
}
});
es.on('error', (error) => {
console.error('SSE Error:', error);
console.error('Event details:', {
type: error.type,
message: error.message,
status: error.status,
readyState: es.readyState
});
// Close the current connection
es.close();
// Attempt to reconnect after a delay
console.error(`Attempting to reconnect in ${RECONNECT_DELAY/1000} seconds...`);
setTimeout(createSSEConnection, RECONNECT_DELAY);
});
return es;
}
// Initialize SSE connection
let es = createSSEConnection();
console.error(`MCP Gateway started. Forwarding messages to ${MCP_POST_URL}`);
console.error('Press Ctrl+C to stop.');
// Handle process termination
process.on('SIGINT', () => {
console.error('\nShutting down MCP Gateway...');
es.close();
process.exit(0);
});
