@modelcontextprotocol/sdk
Version:
Model Context Protocol implementation for TypeScript
112 lines • 4.51 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 node_crypto_1 = require("node:crypto");
const mcp_js_1 = require("../../server/mcp.js");
const streamableHttp_js_1 = require("../../server/streamableHttp.js");
const types_js_1 = require("../../types.js");
// Create an MCP server with implementation details
const server = new mcp_js_1.McpServer({
name: 'resource-list-changed-notification-server',
version: '1.0.0',
});
// Store transports by session ID to send notifications
const transports = {};
const addResource = (name, content) => {
const uri = `https://mcp-example.com/dynamic/${encodeURIComponent(name)}`;
server.resource(name, uri, { mimeType: 'text/plain', description: `Dynamic resource: ${name}` }, async () => {
return {
contents: [{ uri, text: content }],
};
});
};
addResource('example-resource', 'Initial content for example-resource');
const resourceChangeInterval = setInterval(() => {
const name = (0, node_crypto_1.randomUUID)();
addResource(name, `Content for ${name}`);
}, 5000); // Change resources every 5 seconds for testing
const app = (0, express_1.default)();
app.use(express_1.default.json());
app.post('/mcp', async (req, res) => {
console.log('Received MCP request:', req.body);
try {
// Check for existing session ID
const sessionId = req.headers['mcp-session-id'];
let transport;
if (sessionId && transports[sessionId]) {
// Reuse existing transport
transport = transports[sessionId];
}
else if (!sessionId && (0, types_js_1.isInitializeRequest)(req.body)) {
// New initialization request
transport = new streamableHttp_js_1.StreamableHTTPServerTransport({
sessionIdGenerator: () => (0, node_crypto_1.randomUUID)(),
onsessioninitialized: (sessionId) => {
// Store the transport by session ID when session is initialized
// This avoids race conditions where requests might come in before the session is stored
console.log(`Session initialized with ID: ${sessionId}`);
transports[sessionId] = transport;
}
});
// Connect the transport to the MCP server
await server.connect(transport);
// Handle the request - the onsessioninitialized callback will store the transport
await transport.handleRequest(req, res, req.body);
return; // Already handled
}
else {
// Invalid request - no session ID or not initialization request
res.status(400).json({
jsonrpc: '2.0',
error: {
code: -32000,
message: 'Bad Request: No valid session ID provided',
},
id: null,
});
return;
}
// Handle the request with existing transport
await transport.handleRequest(req, res, req.body);
}
catch (error) {
console.error('Error handling MCP request:', error);
if (!res.headersSent) {
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: 'Internal server error',
},
id: null,
});
}
}
});
// Handle GET requests for SSE streams (now using built-in support from StreamableHTTP)
app.get('/mcp', async (req, res) => {
const sessionId = req.headers['mcp-session-id'];
if (!sessionId || !transports[sessionId]) {
res.status(400).send('Invalid or missing session ID');
return;
}
console.log(`Establishing SSE stream for session ${sessionId}`);
const transport = transports[sessionId];
await transport.handleRequest(req, res);
});
// Start the server
const PORT = 3000;
app.listen(PORT, () => {
console.log(`Server listening on port ${PORT}`);
});
// Handle server shutdown
process.on('SIGINT', async () => {
console.log('Shutting down server...');
clearInterval(resourceChangeInterval);
await server.close();
process.exit(0);
});
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