@modelcontextprotocol/sdk
Version:
Model Context Protocol implementation for TypeScript
148 lines • 5.62 kB
JavaScript
;
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const express_1 = __importDefault(require("express"));
const mcp_js_1 = require("../../server/mcp.js");
const sse_js_1 = require("../../server/sse.js");
const zod_1 = require("zod");
/**
* This example server demonstrates the deprecated HTTP+SSE transport
* (protocol version 2024-11-05). It mainly used for testing backward compatible clients.
*
* The server exposes two endpoints:
* - /mcp: For establishing the SSE stream (GET)
* - /messages: For receiving client messages (POST)
*
*/
// Create an MCP server instance
const getServer = () => {
const server = new mcp_js_1.McpServer({
name: 'simple-sse-server',
version: '1.0.0',
}, { capabilities: { logging: {} } });
server.tool('start-notification-stream', 'Starts sending periodic notifications', {
interval: zod_1.z.number().describe('Interval in milliseconds between notifications').default(1000),
count: zod_1.z.number().describe('Number of notifications to send').default(10),
}, async ({ interval, count }, { sendNotification }) => {
const sleep = (ms) => new Promise(resolve => setTimeout(resolve, ms));
let counter = 0;
// Send the initial notification
await sendNotification({
method: "notifications/message",
params: {
level: "info",
data: `Starting notification stream with ${count} messages every ${interval}ms`
}
});
// Send periodic notifications
while (counter < count) {
counter++;
await sleep(interval);
try {
await sendNotification({
method: "notifications/message",
params: {
level: "info",
data: `Notification #${counter} at ${new Date().toISOString()}`
}
});
}
catch (error) {
console.error("Error sending notification:", error);
}
}
return {
content: [
{
type: 'text',
text: `Completed sending ${count} notifications every ${interval}ms`,
}
],
};
});
return server;
};
const app = (0, express_1.default)();
app.use(express_1.default.json());
// Store transports by session ID
const transports = {};
// SSE endpoint for establishing the stream
app.get('/mcp', async (req, res) => {
console.log('Received GET request to /sse (establishing SSE stream)');
try {
// Create a new SSE transport for the client
// The endpoint for POST messages is '/messages'
const transport = new sse_js_1.SSEServerTransport('/messages', res);
// Store the transport by session ID
const sessionId = transport.sessionId;
transports[sessionId] = transport;
// Set up onclose handler to clean up transport when closed
transport.onclose = () => {
console.log(`SSE transport closed for session ${sessionId}`);
delete transports[sessionId];
};
// Connect the transport to the MCP server
const server = getServer();
await server.connect(transport);
console.log(`Established SSE stream with session ID: ${sessionId}`);
}
catch (error) {
console.error('Error establishing SSE stream:', error);
if (!res.headersSent) {
res.status(500).send('Error establishing SSE stream');
}
}
});
// Messages endpoint for receiving client JSON-RPC requests
app.post('/messages', async (req, res) => {
console.log('Received POST request to /messages');
// Extract session ID from URL query parameter
// In the SSE protocol, this is added by the client based on the endpoint event
const sessionId = req.query.sessionId;
if (!sessionId) {
console.error('No session ID provided in request URL');
res.status(400).send('Missing sessionId parameter');
return;
}
const transport = transports[sessionId];
if (!transport) {
console.error(`No active transport found for session ID: ${sessionId}`);
res.status(404).send('Session not found');
return;
}
try {
// Handle the POST message with the transport
await transport.handlePostMessage(req, res, req.body);
}
catch (error) {
console.error('Error handling request:', error);
if (!res.headersSent) {
res.status(500).send('Error handling request');
}
}
});
// Start the server
const PORT = 3000;
app.listen(PORT, () => {
console.log(`Simple SSE Server (deprecated protocol version 2024-11-05) listening on port ${PORT}`);
});
// Handle server shutdown
process.on('SIGINT', async () => {
console.log('Shutting down server...');
// Close all active transports to properly clean up resources
for (const sessionId in transports) {
try {
console.log(`Closing transport for session ${sessionId}`);
await transports[sessionId].close();
delete transports[sessionId];
}
catch (error) {
console.error(`Error closing transport for session ${sessionId}:`, error);
}
}
console.log('Server shutdown complete');
process.exit(0);
});
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