147 lines
5.3 KiB
JavaScript
147 lines
5.3 KiB
JavaScript
import express from 'express';
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import { McpServer } from '../../server/mcp.js';
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import { SSEServerTransport } from '../../server/sse.js';
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import { z } from 'zod';
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/**
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* This example server demonstrates the deprecated HTTP+SSE transport
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* (protocol version 2024-11-05). It mainly used for testing backward compatible clients.
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*
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* The server exposes two endpoints:
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* - /mcp: For establishing the SSE stream (GET)
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* - /messages: For receiving client messages (POST)
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*
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*/
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// Create an MCP server instance
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const getServer = () => {
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const server = new McpServer({
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name: 'simple-sse-server',
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version: '1.0.0',
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}, { capabilities: { logging: {} } });
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server.tool('start-notification-stream', 'Starts sending periodic notifications', {
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interval: z.number().describe('Interval in milliseconds between notifications').default(1000),
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count: z.number().describe('Number of notifications to send').default(10),
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}, async ({ interval, count }, { sendNotification }) => {
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const sleep = (ms) => new Promise(resolve => setTimeout(resolve, ms));
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let counter = 0;
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// Send the initial notification
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await sendNotification({
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method: "notifications/message",
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params: {
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level: "info",
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data: `Starting notification stream with ${count} messages every ${interval}ms`
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}
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});
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// Send periodic notifications
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while (counter < count) {
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counter++;
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await sleep(interval);
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try {
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await sendNotification({
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method: "notifications/message",
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params: {
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level: "info",
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data: `Notification #${counter} at ${new Date().toISOString()}`
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}
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});
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}
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catch (error) {
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console.error("Error sending notification:", error);
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}
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}
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return {
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content: [
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{
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type: 'text',
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text: `Completed sending ${count} notifications every ${interval}ms`,
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}
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],
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};
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});
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return server;
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};
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const app = express();
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app.use(express.json());
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// Store transports by session ID
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const transports = {};
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// SSE endpoint for establishing the stream
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app.get('/mcp', async (req, res) => {
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console.log('Received GET request to /sse (establishing SSE stream)');
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try {
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// Create a new SSE transport for the client
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// The endpoint for POST messages is '/messages'
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const transport = new SSEServerTransport('/messages', res);
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// Store the transport by session ID
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const sessionId = transport.sessionId;
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transports[sessionId] = transport;
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// Set up onclose handler to clean up transport when closed
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transport.onclose = () => {
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console.log(`SSE transport closed for session ${sessionId}`);
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delete transports[sessionId];
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};
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// Connect the transport to the MCP server
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const server = getServer();
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await server.connect(transport);
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console.log(`Established SSE stream with session ID: ${sessionId}`);
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}
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catch (error) {
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console.error('Error establishing SSE stream:', error);
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if (!res.headersSent) {
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res.status(500).send('Error establishing SSE stream');
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}
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}
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});
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// Messages endpoint for receiving client JSON-RPC requests
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app.post('/messages', async (req, res) => {
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console.log('Received POST request to /messages');
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// Extract session ID from URL query parameter
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// In the SSE protocol, this is added by the client based on the endpoint event
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const sessionId = req.query.sessionId;
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if (!sessionId) {
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console.error('No session ID provided in request URL');
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res.status(400).send('Missing sessionId parameter');
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return;
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}
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const transport = transports[sessionId];
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if (!transport) {
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console.error(`No active transport found for session ID: ${sessionId}`);
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res.status(404).send('Session not found');
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return;
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}
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try {
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// Handle the POST message with the transport
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await transport.handlePostMessage(req, res, req.body);
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}
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catch (error) {
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console.error('Error handling request:', error);
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if (!res.headersSent) {
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res.status(500).send('Error handling request');
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}
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}
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});
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// Start the server
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const PORT = 3000;
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app.listen(PORT, (error) => {
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if (error) {
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console.error('Failed to start server:', error);
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process.exit(1);
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}
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console.log(`Simple SSE Server (deprecated protocol version 2024-11-05) listening on port ${PORT}`);
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});
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// Handle server shutdown
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process.on('SIGINT', async () => {
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console.log('Shutting down server...');
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// Close all active transports to properly clean up resources
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for (const sessionId in transports) {
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try {
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console.log(`Closing transport for session ${sessionId}`);
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await transports[sessionId].close();
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delete transports[sessionId];
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}
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catch (error) {
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console.error(`Error closing transport for session ${sessionId}:`, error);
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}
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}
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console.log('Server shutdown complete');
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process.exit(0);
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});
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//# sourceMappingURL=simpleSseServer.js.map
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