107 lines
5.2 KiB
Plaintext
107 lines
5.2 KiB
Plaintext
import * as z from 'zod/v4';
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import express from 'express';
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import cors from 'cors';
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import { verifyChallenge } from 'pkce-challenge';
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import { authenticateClient } from '../middleware/clientAuth.js';
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import { rateLimit } from 'express-rate-limit';
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import { allowedMethods } from '../middleware/allowedMethods.js';
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import { InvalidRequestError, InvalidGrantError, UnsupportedGrantTypeError, ServerError, TooManyRequestsError, OAuthError } from '../errors.js';
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const TokenRequestSchema = z.object({
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grant_type: z.string()
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});
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const AuthorizationCodeGrantSchema = z.object({
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code: z.string(),
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code_verifier: z.string(),
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redirect_uri: z.string().optional(),
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resource: z.string().url().optional()
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});
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const RefreshTokenGrantSchema = z.object({
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refresh_token: z.string(),
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scope: z.string().optional(),
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resource: z.string().url().optional()
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});
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export function tokenHandler({ provider, rateLimit: rateLimitConfig }) {
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// Nested router so we can configure middleware and restrict HTTP method
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const router = express.Router();
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// Configure CORS to allow any origin, to make accessible to web-based MCP clients
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router.use(cors());
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router.use(allowedMethods(['POST']));
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router.use(express.urlencoded({ extended: false }));
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// Apply rate limiting unless explicitly disabled
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if (rateLimitConfig !== false) {
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router.use(rateLimit({
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windowMs: 15 * 60 * 1000, // 15 minutes
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max: 50, // 50 requests per windowMs
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standardHeaders: true,
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legacyHeaders: false,
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message: new TooManyRequestsError('You have exceeded the rate limit for token requests').toResponseObject(),
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...rateLimitConfig
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}));
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}
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// Authenticate and extract client details
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router.use(authenticateClient({ clientsStore: provider.clientsStore }));
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router.post('/', async (req, res) => {
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res.setHeader('Cache-Control', 'no-store');
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try {
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const parseResult = TokenRequestSchema.safeParse(req.body);
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if (!parseResult.success) {
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throw new InvalidRequestError(parseResult.error.message);
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}
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const { grant_type } = parseResult.data;
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const client = req.client;
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if (!client) {
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// This should never happen
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throw new ServerError('Internal Server Error');
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}
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switch (grant_type) {
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case 'authorization_code': {
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const parseResult = AuthorizationCodeGrantSchema.safeParse(req.body);
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if (!parseResult.success) {
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throw new InvalidRequestError(parseResult.error.message);
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}
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const { code, code_verifier, redirect_uri, resource } = parseResult.data;
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const skipLocalPkceValidation = provider.skipLocalPkceValidation;
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// Perform local PKCE validation unless explicitly skipped
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// (e.g. to validate code_verifier in upstream server)
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if (!skipLocalPkceValidation) {
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const codeChallenge = await provider.challengeForAuthorizationCode(client, code);
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if (!(await verifyChallenge(code_verifier, codeChallenge))) {
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throw new InvalidGrantError('code_verifier does not match the challenge');
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}
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}
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// Passes the code_verifier to the provider if PKCE validation didn't occur locally
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const tokens = await provider.exchangeAuthorizationCode(client, code, skipLocalPkceValidation ? code_verifier : undefined, redirect_uri, resource ? new URL(resource) : undefined);
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res.status(200).json(tokens);
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break;
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}
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case 'refresh_token': {
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const parseResult = RefreshTokenGrantSchema.safeParse(req.body);
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if (!parseResult.success) {
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throw new InvalidRequestError(parseResult.error.message);
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}
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const { refresh_token, scope, resource } = parseResult.data;
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const scopes = scope?.split(' ');
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const tokens = await provider.exchangeRefreshToken(client, refresh_token, scopes, resource ? new URL(resource) : undefined);
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res.status(200).json(tokens);
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break;
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}
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// Additional auth methods will not be added on the server side of the SDK.
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case 'client_credentials':
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default:
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throw new UnsupportedGrantTypeError('The grant type is not supported by this authorization server.');
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}
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}
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catch (error) {
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if (error instanceof OAuthError) {
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const status = error instanceof ServerError ? 500 : 400;
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res.status(status).json(error.toResponseObject());
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}
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else {
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const serverError = new ServerError('Internal Server Error');
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res.status(500).json(serverError.toResponseObject());
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}
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}
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});
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return router;
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}
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//# sourceMappingURL=token.js.map |