File size: 29,342 Bytes
a5d718a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 | "use strict";
// Run with: npx tsx src/examples/server/elicitationUrlExample.ts
//
// This example demonstrates how to use URL elicitation to securely collect
// *sensitive* user input in a remote (HTTP) server.
// URL elicitation allows servers to prompt the end-user to open a URL in their browser
// to collect sensitive information.
// Note: See also elicitationFormExample.ts for an example of using form (not URL) elicitation
// to collect *non-sensitive* user input with a structured schema.
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 zod_1 = require("zod");
const mcp_js_1 = require("../../server/mcp.js");
const express_js_1 = require("../../server/express.js");
const streamableHttp_js_1 = require("../../server/streamableHttp.js");
const router_js_1 = require("../../server/auth/router.js");
const bearerAuth_js_1 = require("../../server/auth/middleware/bearerAuth.js");
const types_js_1 = require("../../types.js");
const inMemoryEventStore_js_1 = require("../shared/inMemoryEventStore.js");
const demoInMemoryOAuthProvider_js_1 = require("./demoInMemoryOAuthProvider.js");
const auth_utils_js_1 = require("../../shared/auth-utils.js");
const cors_1 = __importDefault(require("cors"));
// Create an MCP server with implementation details
const getServer = () => {
const mcpServer = new mcp_js_1.McpServer({
name: 'url-elicitation-http-server',
version: '1.0.0'
}, {
capabilities: { logging: {} }
});
mcpServer.registerTool('payment-confirm', {
description: 'A tool that confirms a payment directly with a user',
inputSchema: {
cartId: zod_1.z.string().describe('The ID of the cart to confirm')
}
}, async ({ cartId }, extra) => {
/*
In a real world scenario, there would be some logic here to check if the user has the provided cartId.
For the purposes of this example, we'll throw an error (-> elicits the client to open a URL to confirm payment)
*/
const sessionId = extra.sessionId;
if (!sessionId) {
throw new Error('Expected a Session ID');
}
// Create and track the elicitation
const elicitationId = generateTrackedElicitation(sessionId, elicitationId => mcpServer.server.createElicitationCompletionNotifier(elicitationId));
throw new types_js_1.UrlElicitationRequiredError([
{
mode: 'url',
message: 'This tool requires a payment confirmation. Open the link to confirm payment!',
url: `http://localhost:${MCP_PORT}/confirm-payment?session=${sessionId}&elicitation=${elicitationId}&cartId=${encodeURIComponent(cartId)}`,
elicitationId
}
]);
});
mcpServer.registerTool('third-party-auth', {
description: 'A demo tool that requires third-party OAuth credentials',
inputSchema: {
param1: zod_1.z.string().describe('First parameter')
}
}, async (_, extra) => {
/*
In a real world scenario, there would be some logic here to check if we already have a valid access token for the user.
Auth info (with a subject or `sub` claim) can be typically be found in `extra.authInfo`.
If we do, we can just return the result of the tool call.
If we don't, we can throw an ElicitationRequiredError to request the user to authenticate.
For the purposes of this example, we'll throw an error (-> elicits the client to open a URL to authenticate).
*/
const sessionId = extra.sessionId;
if (!sessionId) {
throw new Error('Expected a Session ID');
}
// Create and track the elicitation
const elicitationId = generateTrackedElicitation(sessionId, elicitationId => mcpServer.server.createElicitationCompletionNotifier(elicitationId));
// Simulate OAuth callback and token exchange after 5 seconds
// In a real app, this would be called from your OAuth callback handler
setTimeout(() => {
console.log(`Simulating OAuth token received for elicitation ${elicitationId}`);
completeURLElicitation(elicitationId);
}, 5000);
throw new types_js_1.UrlElicitationRequiredError([
{
mode: 'url',
message: 'This tool requires access to your example.com account. Open the link to authenticate!',
url: 'https://www.example.com/oauth/authorize',
elicitationId
}
]);
});
return mcpServer;
};
const elicitationsMap = new Map();
// Clean up old elicitations after 1 hour to prevent memory leaks
const ELICITATION_TTL_MS = 60 * 60 * 1000; // 1 hour
const CLEANUP_INTERVAL_MS = 10 * 60 * 1000; // 10 minutes
function cleanupOldElicitations() {
const now = new Date();
for (const [id, metadata] of elicitationsMap.entries()) {
if (now.getTime() - metadata.createdAt.getTime() > ELICITATION_TTL_MS) {
elicitationsMap.delete(id);
console.log(`Cleaned up expired elicitation: ${id}`);
}
}
}
setInterval(cleanupOldElicitations, CLEANUP_INTERVAL_MS);
/**
* Elicitation IDs must be unique strings within the MCP session
* UUIDs are used in this example for simplicity
*/
function generateElicitationId() {
return (0, node_crypto_1.randomUUID)();
}
/**
* Helper function to create and track a new elicitation.
*/
function generateTrackedElicitation(sessionId, createCompletionNotifier) {
const elicitationId = generateElicitationId();
// Create a Promise and its resolver for tracking completion
let completeResolver;
const completedPromise = new Promise(resolve => {
completeResolver = resolve;
});
const completionNotifier = createCompletionNotifier ? createCompletionNotifier(elicitationId) : undefined;
// Store the elicitation in our map
elicitationsMap.set(elicitationId, {
status: 'pending',
completedPromise,
completeResolver: completeResolver,
createdAt: new Date(),
sessionId,
completionNotifier
});
return elicitationId;
}
/**
* Helper function to complete an elicitation.
*/
function completeURLElicitation(elicitationId) {
const elicitation = elicitationsMap.get(elicitationId);
if (!elicitation) {
console.warn(`Attempted to complete unknown elicitation: ${elicitationId}`);
return;
}
if (elicitation.status === 'complete') {
console.warn(`Elicitation already complete: ${elicitationId}`);
return;
}
// Update metadata
elicitation.status = 'complete';
// Send completion notification to the client
if (elicitation.completionNotifier) {
console.log(`Sending notifications/elicitation/complete notification for elicitation ${elicitationId}`);
elicitation.completionNotifier().catch(error => {
console.error(`Failed to send completion notification for elicitation ${elicitationId}:`, error);
});
}
// Resolve the promise to unblock any waiting code
elicitation.completeResolver();
}
const MCP_PORT = process.env.MCP_PORT ? parseInt(process.env.MCP_PORT, 10) : 3000;
const AUTH_PORT = process.env.MCP_AUTH_PORT ? parseInt(process.env.MCP_AUTH_PORT, 10) : 3001;
const app = (0, express_js_1.createMcpExpressApp)();
// Allow CORS all domains, expose the Mcp-Session-Id header
app.use((0, cors_1.default)({
origin: '*', // Allow all origins
exposedHeaders: ['Mcp-Session-Id'],
credentials: true // Allow cookies to be sent cross-origin
}));
// Set up OAuth (required for this example)
let authMiddleware = null;
// Create auth middleware for MCP endpoints
const mcpServerUrl = new URL(`http://localhost:${MCP_PORT}/mcp`);
const authServerUrl = new URL(`http://localhost:${AUTH_PORT}`);
const oauthMetadata = (0, demoInMemoryOAuthProvider_js_1.setupAuthServer)({ authServerUrl, mcpServerUrl, strictResource: true });
const tokenVerifier = {
verifyAccessToken: async (token) => {
const endpoint = oauthMetadata.introspection_endpoint;
if (!endpoint) {
throw new Error('No token verification endpoint available in metadata');
}
const response = await fetch(endpoint, {
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded'
},
body: new URLSearchParams({
token: token
}).toString()
});
if (!response.ok) {
const text = await response.text().catch(() => null);
throw new Error(`Invalid or expired token: ${text}`);
}
const data = await response.json();
if (!data.aud) {
throw new Error(`Resource Indicator (RFC8707) missing`);
}
if (!(0, auth_utils_js_1.checkResourceAllowed)({ requestedResource: data.aud, configuredResource: mcpServerUrl })) {
throw new Error(`Expected resource indicator ${mcpServerUrl}, got: ${data.aud}`);
}
// Convert the response to AuthInfo format
return {
token,
clientId: data.client_id,
scopes: data.scope ? data.scope.split(' ') : [],
expiresAt: data.exp
};
}
};
// Add metadata routes to the main MCP server
app.use((0, router_js_1.mcpAuthMetadataRouter)({
oauthMetadata,
resourceServerUrl: mcpServerUrl,
scopesSupported: ['mcp:tools'],
resourceName: 'MCP Demo Server'
}));
authMiddleware = (0, bearerAuth_js_1.requireBearerAuth)({
verifier: tokenVerifier,
requiredScopes: [],
resourceMetadataUrl: (0, router_js_1.getOAuthProtectedResourceMetadataUrl)(mcpServerUrl)
});
/**
* API Key Form Handling
*
* Many servers today require an API key to operate, but there's no scalable way to do this dynamically for remote servers within MCP protocol.
* URL-mode elicitation enables the server to host a simple form and get the secret data securely from the user without involving the LLM or client.
**/
async function sendApiKeyElicitation(sessionId, sender, createCompletionNotifier) {
if (!sessionId) {
console.error('No session ID provided');
throw new Error('Expected a Session ID to track elicitation');
}
console.log('π URL elicitation demo: Requesting API key from client...');
const elicitationId = generateTrackedElicitation(sessionId, createCompletionNotifier);
try {
const result = await sender({
mode: 'url',
message: 'Please provide your API key to authenticate with this server',
// Host the form on the same server. In a real app, you might coordinate passing these state variables differently.
url: `http://localhost:${MCP_PORT}/api-key-form?session=${sessionId}&elicitation=${elicitationId}`,
elicitationId
});
switch (result.action) {
case 'accept':
console.log('π URL elicitation demo: Client accepted the API key elicitation (now pending form submission)');
// Wait for the API key to be submitted via the form
// The form submission will complete the elicitation
break;
default:
console.log('π URL elicitation demo: Client declined to provide an API key');
// In a real app, this might close the connection, but for the demo, we'll continue
break;
}
}
catch (error) {
console.error('Error during API key elicitation:', error);
}
}
// API Key Form endpoint - serves a simple HTML form
app.get('/api-key-form', (req, res) => {
const mcpSessionId = req.query.session;
const elicitationId = req.query.elicitation;
if (!mcpSessionId || !elicitationId) {
res.status(400).send('<h1>Error</h1><p>Missing required parameters</p>');
return;
}
// Check for user session cookie
// In production, this is often handled by some user auth middleware to ensure the user has a valid session
// This session is different from the MCP session.
// This userSession is the cookie that the MCP Server's Authorization Server sets for the user when they log in.
const userSession = getUserSessionCookie(req.headers.cookie);
if (!userSession) {
res.status(401).send('<h1>Error</h1><p>Unauthorized - please reconnect to login again</p>');
return;
}
// Serve a simple HTML form
res.send(`
<!DOCTYPE html>
<html>
<head>
<title>Submit Your API Key</title>
<style>
body { font-family: sans-serif; max-width: 400px; margin: 50px auto; padding: 20px; }
input[type="text"] { width: 100%; padding: 8px; margin: 10px 0; box-sizing: border-box; }
button { background: #007bff; color: white; padding: 10px 20px; border: none; cursor: pointer; }
button:hover { background: #0056b3; }
.user { background: #d1ecf1; padding: 8px; margin-bottom: 10px; }
.info { color: #666; font-size: 0.9em; margin-top: 20px; }
</style>
</head>
<body>
<h1>API Key Required</h1>
<div class="user">β Logged in as: <strong>${userSession.name}</strong></div>
<form method="POST" action="/api-key-form">
<input type="hidden" name="session" value="${mcpSessionId}" />
<input type="hidden" name="elicitation" value="${elicitationId}" />
<label>API Key:<br>
<input type="text" name="apiKey" required placeholder="Enter your API key" />
</label>
<button type="submit">Submit</button>
</form>
<div class="info">This is a demo showing how a server can securely elicit sensitive data from a user using a URL.</div>
</body>
</html>
`);
});
// Handle API key form submission
app.post('/api-key-form', express_1.default.urlencoded(), (req, res) => {
const { session: sessionId, apiKey, elicitation: elicitationId } = req.body;
if (!sessionId || !apiKey || !elicitationId) {
res.status(400).send('<h1>Error</h1><p>Missing required parameters</p>');
return;
}
// Check for user session cookie here too
const userSession = getUserSessionCookie(req.headers.cookie);
if (!userSession) {
res.status(401).send('<h1>Error</h1><p>Unauthorized - please reconnect to login again</p>');
return;
}
// A real app might store this API key to be used later for the user.
console.log(`π Received API key \x1b[32m${apiKey}\x1b[0m for session ${sessionId}`);
// If we have an elicitationId, complete the elicitation
completeURLElicitation(elicitationId);
// Send a success response
res.send(`
<!DOCTYPE html>
<html>
<head>
<title>Success</title>
<style>
body { font-family: sans-serif; max-width: 400px; margin: 50px auto; padding: 20px; text-align: center; }
.success { background: #d4edda; color: #155724; padding: 20px; margin: 20px 0; }
</style>
</head>
<body>
<div class="success">
<h1>Success β</h1>
<p>API key received.</p>
</div>
<p>You can close this window and return to your MCP client.</p>
</body>
</html>
`);
});
// Helper to get the user session from the demo_session cookie
function getUserSessionCookie(cookieHeader) {
if (!cookieHeader)
return null;
const cookies = cookieHeader.split(';');
for (const cookie of cookies) {
const [name, value] = cookie.trim().split('=');
if (name === 'demo_session' && value) {
try {
return JSON.parse(decodeURIComponent(value));
}
catch (error) {
console.error('Failed to parse demo_session cookie:', error);
return null;
}
}
}
return null;
}
/**
* Payment Confirmation Form Handling
*
* This demonstrates how a server can use URL-mode elicitation to get user confirmation
* for sensitive operations like payment processing.
**/
// Payment Confirmation Form endpoint - serves a simple HTML form
app.get('/confirm-payment', (req, res) => {
const mcpSessionId = req.query.session;
const elicitationId = req.query.elicitation;
const cartId = req.query.cartId;
if (!mcpSessionId || !elicitationId) {
res.status(400).send('<h1>Error</h1><p>Missing required parameters</p>');
return;
}
// Check for user session cookie
// In production, this is often handled by some user auth middleware to ensure the user has a valid session
// This session is different from the MCP session.
// This userSession is the cookie that the MCP Server's Authorization Server sets for the user when they log in.
const userSession = getUserSessionCookie(req.headers.cookie);
if (!userSession) {
res.status(401).send('<h1>Error</h1><p>Unauthorized - please reconnect to login again</p>');
return;
}
// Serve a simple HTML form
res.send(`
<!DOCTYPE html>
<html>
<head>
<title>Confirm Payment</title>
<style>
body { font-family: sans-serif; max-width: 400px; margin: 50px auto; padding: 20px; }
button { background: #28a745; color: white; padding: 12px 24px; border: none; cursor: pointer; font-size: 16px; width: 100%; margin: 10px 0; }
button:hover { background: #218838; }
button.cancel { background: #6c757d; }
button.cancel:hover { background: #5a6268; }
.user { background: #d1ecf1; padding: 8px; margin-bottom: 10px; }
.cart-info { background: #f8f9fa; padding: 12px; margin: 15px 0; border-left: 4px solid #007bff; }
.info { color: #666; font-size: 0.9em; margin-top: 20px; }
.warning { background: #fff3cd; color: #856404; padding: 12px; margin: 15px 0; border-left: 4px solid #ffc107; }
</style>
</head>
<body>
<h1>Confirm Payment</h1>
<div class="user">β Logged in as: <strong>${userSession.name}</strong></div>
${cartId ? `<div class="cart-info"><strong>Cart ID:</strong> ${cartId}</div>` : ''}
<div class="warning">
<strong>β οΈ Please review your order before confirming.</strong>
</div>
<form method="POST" action="/confirm-payment">
<input type="hidden" name="session" value="${mcpSessionId}" />
<input type="hidden" name="elicitation" value="${elicitationId}" />
${cartId ? `<input type="hidden" name="cartId" value="${cartId}" />` : ''}
<button type="submit" name="action" value="confirm">Confirm Payment</button>
<button type="submit" name="action" value="cancel" class="cancel">Cancel</button>
</form>
<div class="info">This is a demo showing how a server can securely get user confirmation for sensitive operations using URL-mode elicitation.</div>
</body>
</html>
`);
});
// Handle Payment Confirmation form submission
app.post('/confirm-payment', express_1.default.urlencoded(), (req, res) => {
const { session: sessionId, elicitation: elicitationId, cartId, action } = req.body;
if (!sessionId || !elicitationId) {
res.status(400).send('<h1>Error</h1><p>Missing required parameters</p>');
return;
}
// Check for user session cookie here too
const userSession = getUserSessionCookie(req.headers.cookie);
if (!userSession) {
res.status(401).send('<h1>Error</h1><p>Unauthorized - please reconnect to login again</p>');
return;
}
if (action === 'confirm') {
// A real app would process the payment here
console.log(`π³ Payment confirmed for cart ${cartId || 'unknown'} by user ${userSession.name} (session ${sessionId})`);
// Complete the elicitation
completeURLElicitation(elicitationId);
// Send a success response
res.send(`
<!DOCTYPE html>
<html>
<head>
<title>Payment Confirmed</title>
<style>
body { font-family: sans-serif; max-width: 400px; margin: 50px auto; padding: 20px; text-align: center; }
.success { background: #d4edda; color: #155724; padding: 20px; margin: 20px 0; }
</style>
</head>
<body>
<div class="success">
<h1>Payment Confirmed β</h1>
<p>Your payment has been successfully processed.</p>
${cartId ? `<p><strong>Cart ID:</strong> ${cartId}</p>` : ''}
</div>
<p>You can close this window and return to your MCP client.</p>
</body>
</html>
`);
}
else if (action === 'cancel') {
console.log(`π³ Payment cancelled for cart ${cartId || 'unknown'} by user ${userSession.name} (session ${sessionId})`);
// The client will still receive a notifications/elicitation/complete notification,
// which indicates that the out-of-band interaction is complete (but not necessarily successful)
completeURLElicitation(elicitationId);
res.send(`
<!DOCTYPE html>
<html>
<head>
<title>Payment Cancelled</title>
<style>
body { font-family: sans-serif; max-width: 400px; margin: 50px auto; padding: 20px; text-align: center; }
.info { background: #d1ecf1; color: #0c5460; padding: 20px; margin: 20px 0; }
</style>
</head>
<body>
<div class="info">
<h1>Payment Cancelled</h1>
<p>Your payment has been cancelled.</p>
</div>
<p>You can close this window and return to your MCP client.</p>
</body>
</html>
`);
}
else {
res.status(400).send('<h1>Error</h1><p>Invalid action</p>');
}
});
// Map to store transports by session ID
const transports = {};
const sessionsNeedingElicitation = {};
// MCP POST endpoint
const mcpPostHandler = async (req, res) => {
const sessionId = req.headers['mcp-session-id'];
console.debug(`Received MCP POST for session: ${sessionId || 'unknown'}`);
try {
let transport;
if (sessionId && transports[sessionId]) {
// Reuse existing transport
transport = transports[sessionId];
}
else if (!sessionId && (0, types_js_1.isInitializeRequest)(req.body)) {
const server = getServer();
// New initialization request
const eventStore = new inMemoryEventStore_js_1.InMemoryEventStore();
transport = new streamableHttp_js_1.StreamableHTTPServerTransport({
sessionIdGenerator: () => (0, node_crypto_1.randomUUID)(),
eventStore, // Enable resumability
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;
sessionsNeedingElicitation[sessionId] = {
elicitationSender: params => server.server.elicitInput(params),
createCompletionNotifier: elicitationId => server.server.createElicitationCompletionNotifier(elicitationId)
};
}
});
// Set up onclose handler to clean up transport when closed
transport.onclose = () => {
const sid = transport.sessionId;
if (sid && transports[sid]) {
console.log(`Transport closed for session ${sid}, removing from transports map`);
delete transports[sid];
delete sessionsNeedingElicitation[sid];
}
};
// Connect the transport to the MCP server BEFORE handling the request
// so responses can flow back through the same transport
await server.connect(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 - no need to reconnect
// The existing transport is already connected to the server
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
});
}
}
};
// Set up routes with auth middleware
app.post('/mcp', authMiddleware, mcpPostHandler);
// Handle GET requests for SSE streams (using built-in support from StreamableHTTP)
const mcpGetHandler = async (req, res) => {
const sessionId = req.headers['mcp-session-id'];
if (!sessionId || !transports[sessionId]) {
res.status(400).send('Invalid or missing session ID');
return;
}
// Check for Last-Event-ID header for resumability
const lastEventId = req.headers['last-event-id'];
if (lastEventId) {
console.log(`Client reconnecting with Last-Event-ID: ${lastEventId}`);
}
else {
console.log(`Establishing new SSE stream for session ${sessionId}`);
}
const transport = transports[sessionId];
await transport.handleRequest(req, res);
if (sessionsNeedingElicitation[sessionId]) {
const { elicitationSender, createCompletionNotifier } = sessionsNeedingElicitation[sessionId];
// Send an elicitation request to the client in the background
sendApiKeyElicitation(sessionId, elicitationSender, createCompletionNotifier)
.then(() => {
// Only delete on successful send for this demo
delete sessionsNeedingElicitation[sessionId];
console.log(`π URL elicitation demo: Finished sending API key elicitation request for session ${sessionId}`);
})
.catch(error => {
console.error('Error sending API key elicitation:', error);
// Keep in map to potentially retry on next reconnect
});
}
};
// Set up GET route with conditional auth middleware
app.get('/mcp', authMiddleware, mcpGetHandler);
// Handle DELETE requests for session termination (according to MCP spec)
const mcpDeleteHandler = 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(`Received session termination request for session ${sessionId}`);
try {
const transport = transports[sessionId];
await transport.handleRequest(req, res);
}
catch (error) {
console.error('Error handling session termination:', error);
if (!res.headersSent) {
res.status(500).send('Error processing session termination');
}
}
};
// Set up DELETE route with auth middleware
app.delete('/mcp', authMiddleware, mcpDeleteHandler);
app.listen(MCP_PORT, error => {
if (error) {
console.error('Failed to start server:', error);
process.exit(1);
}
console.log(`MCP Streamable HTTP Server listening on port ${MCP_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];
delete sessionsNeedingElicitation[sessionId];
}
catch (error) {
console.error(`Error closing transport for session ${sessionId}:`, error);
}
}
console.log('Server shutdown complete');
process.exit(0);
});
//# sourceMappingURL=elicitationUrlExample.js.map |