@modelcontextprotocol/sdk
Version:
Model Context Protocol implementation for TypeScript
72 lines • 3.43 kB
JavaScript
import { InsufficientScopeError, InvalidTokenError, OAuthError, ServerError } from '../errors.js';
/**
* Middleware that requires a valid Bearer token in the Authorization header.
*
* This will validate the token with the auth provider and add the resulting auth info to the request object.
*
* If resourceMetadataUrl is provided, it will be included in the WWW-Authenticate header
* for 401 responses as per the OAuth 2.0 Protected Resource Metadata spec.
*/
export function requireBearerAuth({ verifier, requiredScopes = [], resourceMetadataUrl }) {
return async (req, res, next) => {
try {
const authHeader = req.headers.authorization;
if (!authHeader) {
throw new InvalidTokenError('Missing Authorization header');
}
const [type, token] = authHeader.split(' ');
if (type.toLowerCase() !== 'bearer' || !token) {
throw new InvalidTokenError("Invalid Authorization header format, expected 'Bearer TOKEN'");
}
const authInfo = await verifier.verifyAccessToken(token);
// Check if token has the required scopes (if any)
if (requiredScopes.length > 0) {
const hasAllScopes = requiredScopes.every(scope => authInfo.scopes.includes(scope));
if (!hasAllScopes) {
throw new InsufficientScopeError('Insufficient scope');
}
}
// Check if the token is set to expire or if it is expired
if (typeof authInfo.expiresAt !== 'number' || isNaN(authInfo.expiresAt)) {
throw new InvalidTokenError('Token has no expiration time');
}
else if (authInfo.expiresAt < Date.now() / 1000) {
throw new InvalidTokenError('Token has expired');
}
req.auth = authInfo;
next();
}
catch (error) {
// Build WWW-Authenticate header parts
const buildWwwAuthHeader = (errorCode, message) => {
let header = `Bearer error="${errorCode}", error_description="${message}"`;
if (requiredScopes.length > 0) {
header += `, scope="${requiredScopes.join(' ')}"`;
}
if (resourceMetadataUrl) {
header += `, resource_metadata="${resourceMetadataUrl}"`;
}
return header;
};
if (error instanceof InvalidTokenError) {
res.set('WWW-Authenticate', buildWwwAuthHeader(error.errorCode, error.message));
res.status(401).json(error.toResponseObject());
}
else if (error instanceof InsufficientScopeError) {
res.set('WWW-Authenticate', buildWwwAuthHeader(error.errorCode, error.message));
res.status(403).json(error.toResponseObject());
}
else if (error instanceof ServerError) {
res.status(500).json(error.toResponseObject());
}
else if (error instanceof OAuthError) {
res.status(400).json(error.toResponseObject());
}
else {
const serverError = new ServerError('Internal Server Error');
res.status(500).json(serverError.toResponseObject());
}
}
};
}
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