auth.js•25.3 kB
import pkceChallenge from "pkce-challenge";
import { LATEST_PROTOCOL_VERSION } from "../types.js";
import { OAuthErrorResponseSchema } from "../shared/auth.js";
import { OAuthClientInformationFullSchema, OAuthMetadataSchema, OAuthProtectedResourceMetadataSchema, OAuthTokensSchema } from "../shared/auth.js";
import { checkResourceAllowed, resourceUrlFromServerUrl } from "../shared/auth-utils.js";
import { InvalidClientError, InvalidGrantError, OAUTH_ERRORS, OAuthError, ServerError, UnauthorizedClientError } from "../server/auth/errors.js";
export class UnauthorizedError extends Error {
constructor(message) {
super(message !== null && message !== void 0 ? message : "Unauthorized");
}
}
/**
* Determines the best client authentication method to use based on server support and client configuration.
*
* Priority order (highest to lowest):
* 1. client_secret_basic (if client secret is available)
* 2. client_secret_post (if client secret is available)
* 3. none (for public clients)
*
* @param clientInformation - OAuth client information containing credentials
* @param supportedMethods - Authentication methods supported by the authorization server
* @returns The selected authentication method
*/
function selectClientAuthMethod(clientInformation, supportedMethods) {
const hasClientSecret = clientInformation.client_secret !== undefined;
// If server doesn't specify supported methods, use RFC 6749 defaults
if (supportedMethods.length === 0) {
return hasClientSecret ? "client_secret_post" : "none";
}
// Try methods in priority order (most secure first)
if (hasClientSecret && supportedMethods.includes("client_secret_basic")) {
return "client_secret_basic";
}
if (hasClientSecret && supportedMethods.includes("client_secret_post")) {
return "client_secret_post";
}
if (supportedMethods.includes("none")) {
return "none";
}
// Fallback: use what we have
return hasClientSecret ? "client_secret_post" : "none";
}
/**
* Applies client authentication to the request based on the specified method.
*
* Implements OAuth 2.1 client authentication methods:
* - client_secret_basic: HTTP Basic authentication (RFC 6749 Section 2.3.1)
* - client_secret_post: Credentials in request body (RFC 6749 Section 2.3.1)
* - none: Public client authentication (RFC 6749 Section 2.1)
*
* @param method - The authentication method to use
* @param clientInformation - OAuth client information containing credentials
* @param headers - HTTP headers object to modify
* @param params - URL search parameters to modify
* @throws {Error} When required credentials are missing
*/
function applyClientAuthentication(method, clientInformation, headers, params) {
const { client_id, client_secret } = clientInformation;
switch (method) {
case "client_secret_basic":
applyBasicAuth(client_id, client_secret, headers);
return;
case "client_secret_post":
applyPostAuth(client_id, client_secret, params);
return;
case "none":
applyPublicAuth(client_id, params);
return;
default:
throw new Error(`Unsupported client authentication method: ${method}`);
}
}
/**
* Applies HTTP Basic authentication (RFC 6749 Section 2.3.1)
*/
function applyBasicAuth(clientId, clientSecret, headers) {
if (!clientSecret) {
throw new Error("client_secret_basic authentication requires a client_secret");
}
const credentials = btoa(`${clientId}:${clientSecret}`);
headers.set("Authorization", `Basic ${credentials}`);
}
/**
* Applies POST body authentication (RFC 6749 Section 2.3.1)
*/
function applyPostAuth(clientId, clientSecret, params) {
params.set("client_id", clientId);
if (clientSecret) {
params.set("client_secret", clientSecret);
}
}
/**
* Applies public client authentication (RFC 6749 Section 2.1)
*/
function applyPublicAuth(clientId, params) {
params.set("client_id", clientId);
}
/**
* Parses an OAuth error response from a string or Response object.
*
* If the input is a standard OAuth2.0 error response, it will be parsed according to the spec
* and an instance of the appropriate OAuthError subclass will be returned.
* If parsing fails, it falls back to a generic ServerError that includes
* the response status (if available) and original content.
*
* @param input - A Response object or string containing the error response
* @returns A Promise that resolves to an OAuthError instance
*/
export async function parseErrorResponse(input) {
const statusCode = input instanceof Response ? input.status : undefined;
const body = input instanceof Response ? await input.text() : input;
try {
const result = OAuthErrorResponseSchema.parse(JSON.parse(body));
const { error, error_description, error_uri } = result;
const errorClass = OAUTH_ERRORS[error] || ServerError;
return new errorClass(error_description || '', error_uri);
}
catch (error) {
// Not a valid OAuth error response, but try to inform the user of the raw data anyway
const errorMessage = `${statusCode ? `HTTP ${statusCode}: ` : ''}Invalid OAuth error response: ${error}. Raw body: ${body}`;
return new ServerError(errorMessage);
}
}
/**
* Orchestrates the full auth flow with a server.
*
* This can be used as a single entry point for all authorization functionality,
* instead of linking together the other lower-level functions in this module.
*/
export async function auth(provider, options) {
var _a, _b;
try {
return await authInternal(provider, options);
}
catch (error) {
// Handle recoverable error types by invalidating credentials and retrying
if (error instanceof InvalidClientError || error instanceof UnauthorizedClientError) {
await ((_a = provider.invalidateCredentials) === null || _a === void 0 ? void 0 : _a.call(provider, 'all'));
return await authInternal(provider, options);
}
else if (error instanceof InvalidGrantError) {
await ((_b = provider.invalidateCredentials) === null || _b === void 0 ? void 0 : _b.call(provider, 'tokens'));
return await authInternal(provider, options);
}
// Throw otherwise
throw error;
}
}
async function authInternal(provider, { serverUrl, authorizationCode, scope, resourceMetadataUrl, fetchFn, }) {
let resourceMetadata;
let authorizationServerUrl = serverUrl;
try {
resourceMetadata = await discoverOAuthProtectedResourceMetadata(serverUrl, { resourceMetadataUrl }, fetchFn);
if (resourceMetadata.authorization_servers && resourceMetadata.authorization_servers.length > 0) {
authorizationServerUrl = resourceMetadata.authorization_servers[0];
}
}
catch (_a) {
// Ignore errors and fall back to /.well-known/oauth-authorization-server
}
const resource = await selectResourceURL(serverUrl, provider, resourceMetadata);
const metadata = await discoverOAuthMetadata(serverUrl, {
authorizationServerUrl
}, fetchFn);
// Handle client registration if needed
let clientInformation = await Promise.resolve(provider.clientInformation());
if (!clientInformation) {
if (authorizationCode !== undefined) {
throw new Error("Existing OAuth client information is required when exchanging an authorization code");
}
if (!provider.saveClientInformation) {
throw new Error("OAuth client information must be saveable for dynamic registration");
}
const fullInformation = await registerClient(authorizationServerUrl, {
metadata,
clientMetadata: provider.clientMetadata,
});
await provider.saveClientInformation(fullInformation);
clientInformation = fullInformation;
}
// Exchange authorization code for tokens
if (authorizationCode !== undefined) {
const codeVerifier = await provider.codeVerifier();
const tokens = await exchangeAuthorization(authorizationServerUrl, {
metadata,
clientInformation,
authorizationCode,
codeVerifier,
redirectUri: provider.redirectUrl,
resource,
addClientAuthentication: provider.addClientAuthentication,
fetchFn: fetchFn,
});
await provider.saveTokens(tokens);
return "AUTHORIZED";
}
const tokens = await provider.tokens();
// Handle token refresh or new authorization
if (tokens === null || tokens === void 0 ? void 0 : tokens.refresh_token) {
try {
// Attempt to refresh the token
const newTokens = await refreshAuthorization(authorizationServerUrl, {
metadata,
clientInformation,
refreshToken: tokens.refresh_token,
resource,
addClientAuthentication: provider.addClientAuthentication,
});
await provider.saveTokens(newTokens);
return "AUTHORIZED";
}
catch (error) {
// If this is a ServerError, or an unknown type, log it out and try to continue. Otherwise, escalate so we can fix things and retry.
if (!(error instanceof OAuthError) || error instanceof ServerError) {
// Could not refresh OAuth tokens
}
else {
// Refresh failed for another reason, re-throw
throw error;
}
}
}
const state = provider.state ? await provider.state() : undefined;
// Start new authorization flow
const { authorizationUrl, codeVerifier } = await startAuthorization(authorizationServerUrl, {
metadata,
clientInformation,
state,
redirectUrl: provider.redirectUrl,
scope: scope || provider.clientMetadata.scope,
resource,
});
await provider.saveCodeVerifier(codeVerifier);
await provider.redirectToAuthorization(authorizationUrl);
return "REDIRECT";
}
export async function selectResourceURL(serverUrl, provider, resourceMetadata) {
const defaultResource = resourceUrlFromServerUrl(serverUrl);
// If provider has custom validation, delegate to it
if (provider.validateResourceURL) {
return await provider.validateResourceURL(defaultResource, resourceMetadata === null || resourceMetadata === void 0 ? void 0 : resourceMetadata.resource);
}
// Only include resource parameter when Protected Resource Metadata is present
if (!resourceMetadata) {
return undefined;
}
// Validate that the metadata's resource is compatible with our request
if (!checkResourceAllowed({ requestedResource: defaultResource, configuredResource: resourceMetadata.resource })) {
throw new Error(`Protected resource ${resourceMetadata.resource} does not match expected ${defaultResource} (or origin)`);
}
// Prefer the resource from metadata since it's what the server is telling us to request
return new URL(resourceMetadata.resource);
}
/**
* Extract resource_metadata from response header.
*/
export function extractResourceMetadataUrl(res) {
const authenticateHeader = res.headers.get("WWW-Authenticate");
if (!authenticateHeader) {
return undefined;
}
const [type, scheme] = authenticateHeader.split(' ');
if (type.toLowerCase() !== 'bearer' || !scheme) {
return undefined;
}
const regex = /resource_metadata="([^"]*)"/;
const match = regex.exec(authenticateHeader);
if (!match) {
return undefined;
}
try {
return new URL(match[1]);
}
catch (_a) {
return undefined;
}
}
/**
* Looks up RFC 9728 OAuth 2.0 Protected Resource Metadata.
*
* If the server returns a 404 for the well-known endpoint, this function will
* return `undefined`. Any other errors will be thrown as exceptions.
*/
export async function discoverOAuthProtectedResourceMetadata(serverUrl, opts, fetchFn = fetch) {
const response = await discoverMetadataWithFallback(serverUrl, 'oauth-protected-resource', fetchFn, {
protocolVersion: opts === null || opts === void 0 ? void 0 : opts.protocolVersion,
metadataUrl: opts === null || opts === void 0 ? void 0 : opts.resourceMetadataUrl,
});
if (!response || response.status === 404) {
throw new Error(`Resource server does not implement OAuth 2.0 Protected Resource Metadata.`);
}
if (!response.ok) {
throw new Error(`HTTP ${response.status} trying to load well-known OAuth protected resource metadata.`);
}
return OAuthProtectedResourceMetadataSchema.parse(await response.json());
}
/**
* Helper function to handle fetch with CORS retry logic
*/
async function fetchWithCorsRetry(url, headers, fetchFn = fetch) {
try {
return await fetchFn(url, { headers });
}
catch (error) {
if (error instanceof TypeError) {
if (headers) {
// CORS errors come back as TypeError, retry without headers
return fetchWithCorsRetry(url, undefined, fetchFn);
}
else {
// We're getting CORS errors on retry too, return undefined
return undefined;
}
}
throw error;
}
}
/**
* Constructs the well-known path for OAuth metadata discovery
*/
function buildWellKnownPath(wellKnownPrefix, pathname) {
let wellKnownPath = `/.well-known/${wellKnownPrefix}${pathname}`;
if (pathname.endsWith('/')) {
// Strip trailing slash from pathname to avoid double slashes
wellKnownPath = wellKnownPath.slice(0, -1);
}
return wellKnownPath;
}
/**
* Tries to discover OAuth metadata at a specific URL
*/
async function tryMetadataDiscovery(url, protocolVersion, fetchFn = fetch) {
const headers = {
"MCP-Protocol-Version": protocolVersion
};
return await fetchWithCorsRetry(url, headers, fetchFn);
}
/**
* Determines if fallback to root discovery should be attempted
*/
function shouldAttemptFallback(response, pathname) {
return !response || response.status === 404 && pathname !== '/';
}
/**
* Generic function for discovering OAuth metadata with fallback support
*/
async function discoverMetadataWithFallback(serverUrl, wellKnownType, fetchFn, opts) {
var _a, _b;
const issuer = new URL(serverUrl);
const protocolVersion = (_a = opts === null || opts === void 0 ? void 0 : opts.protocolVersion) !== null && _a !== void 0 ? _a : LATEST_PROTOCOL_VERSION;
let url;
if (opts === null || opts === void 0 ? void 0 : opts.metadataUrl) {
url = new URL(opts.metadataUrl);
}
else {
// Try path-aware discovery first
const wellKnownPath = buildWellKnownPath(wellKnownType, issuer.pathname);
url = new URL(wellKnownPath, (_b = opts === null || opts === void 0 ? void 0 : opts.metadataServerUrl) !== null && _b !== void 0 ? _b : issuer);
url.search = issuer.search;
}
let response = await tryMetadataDiscovery(url, protocolVersion, fetchFn);
// If path-aware discovery fails with 404 and we're not already at root, try fallback to root discovery
if (!(opts === null || opts === void 0 ? void 0 : opts.metadataUrl) && shouldAttemptFallback(response, issuer.pathname)) {
const rootUrl = new URL(`/.well-known/${wellKnownType}`, issuer);
response = await tryMetadataDiscovery(rootUrl, protocolVersion, fetchFn);
}
return response;
}
/**
* Looks up RFC 8414 OAuth 2.0 Authorization Server Metadata.
*
* If the server returns a 404 for the well-known endpoint, this function will
* return `undefined`. Any other errors will be thrown as exceptions.
*/
export async function discoverOAuthMetadata(issuer, { authorizationServerUrl, protocolVersion, } = {}, fetchFn = fetch) {
if (typeof issuer === 'string') {
issuer = new URL(issuer);
}
if (!authorizationServerUrl) {
authorizationServerUrl = issuer;
}
if (typeof authorizationServerUrl === 'string') {
authorizationServerUrl = new URL(authorizationServerUrl);
}
protocolVersion !== null && protocolVersion !== void 0 ? protocolVersion : (protocolVersion = LATEST_PROTOCOL_VERSION);
const response = await discoverMetadataWithFallback(authorizationServerUrl, 'oauth-authorization-server', fetchFn, {
protocolVersion,
metadataServerUrl: authorizationServerUrl,
});
if (!response || response.status === 404) {
return undefined;
}
if (!response.ok) {
throw new Error(`HTTP ${response.status} trying to load well-known OAuth metadata`);
}
return OAuthMetadataSchema.parse(await response.json());
}
/**
* Begins the authorization flow with the given server, by generating a PKCE challenge and constructing the authorization URL.
*/
export async function startAuthorization(authorizationServerUrl, { metadata, clientInformation, redirectUrl, scope, state, resource, }) {
const responseType = "code";
const codeChallengeMethod = "S256";
let authorizationUrl;
if (metadata) {
authorizationUrl = new URL(metadata.authorization_endpoint);
if (!metadata.response_types_supported.includes(responseType)) {
throw new Error(`Incompatible auth server: does not support response type ${responseType}`);
}
if (!metadata.code_challenge_methods_supported ||
!metadata.code_challenge_methods_supported.includes(codeChallengeMethod)) {
throw new Error(`Incompatible auth server: does not support code challenge method ${codeChallengeMethod}`);
}
}
else {
authorizationUrl = new URL("/authorize", authorizationServerUrl);
}
// Generate PKCE challenge
const challenge = await pkceChallenge();
const codeVerifier = challenge.code_verifier;
const codeChallenge = challenge.code_challenge;
authorizationUrl.searchParams.set("response_type", responseType);
authorizationUrl.searchParams.set("client_id", clientInformation.client_id);
authorizationUrl.searchParams.set("code_challenge", codeChallenge);
authorizationUrl.searchParams.set("code_challenge_method", codeChallengeMethod);
authorizationUrl.searchParams.set("redirect_uri", String(redirectUrl));
if (state) {
authorizationUrl.searchParams.set("state", state);
}
if (scope) {
authorizationUrl.searchParams.set("scope", scope);
}
if (scope === null || scope === void 0 ? void 0 : scope.includes("offline_access")) {
// if the request includes the OIDC-only "offline_access" scope,
// we need to set the prompt to "consent" to ensure the user is prompted to grant offline access
// https://openid.net/specs/openid-connect-core-1_0.html#OfflineAccess
authorizationUrl.searchParams.append("prompt", "consent");
}
if (resource) {
authorizationUrl.searchParams.set("resource", resource.href);
}
return { authorizationUrl, codeVerifier };
}
/**
* Exchanges an authorization code for an access token with the given server.
*
* Supports multiple client authentication methods as specified in OAuth 2.1:
* - Automatically selects the best authentication method based on server support
* - Falls back to appropriate defaults when server metadata is unavailable
*
* @param authorizationServerUrl - The authorization server's base URL
* @param options - Configuration object containing client info, auth code, etc.
* @returns Promise resolving to OAuth tokens
* @throws {Error} When token exchange fails or authentication is invalid
*/
export async function exchangeAuthorization(authorizationServerUrl, { metadata, clientInformation, authorizationCode, codeVerifier, redirectUri, resource, addClientAuthentication, fetchFn, }) {
var _a;
const grantType = "authorization_code";
const tokenUrl = (metadata === null || metadata === void 0 ? void 0 : metadata.token_endpoint)
? new URL(metadata.token_endpoint)
: new URL("/token", authorizationServerUrl);
if ((metadata === null || metadata === void 0 ? void 0 : metadata.grant_types_supported) &&
!metadata.grant_types_supported.includes(grantType)) {
throw new Error(`Incompatible auth server: does not support grant type ${grantType}`);
}
// Exchange code for tokens
const headers = new Headers({
"Content-Type": "application/x-www-form-urlencoded",
});
const params = new URLSearchParams({
grant_type: grantType,
code: authorizationCode,
code_verifier: codeVerifier,
redirect_uri: String(redirectUri),
});
if (addClientAuthentication) {
addClientAuthentication(headers, params, authorizationServerUrl, metadata);
}
else {
// Determine and apply client authentication method
const supportedMethods = (_a = metadata === null || metadata === void 0 ? void 0 : metadata.token_endpoint_auth_methods_supported) !== null && _a !== void 0 ? _a : [];
const authMethod = selectClientAuthMethod(clientInformation, supportedMethods);
applyClientAuthentication(authMethod, clientInformation, headers, params);
}
if (resource) {
params.set("resource", resource.href);
}
const response = await (fetchFn !== null && fetchFn !== void 0 ? fetchFn : fetch)(tokenUrl, {
method: "POST",
headers,
body: params,
});
if (!response.ok) {
throw await parseErrorResponse(response);
}
return OAuthTokensSchema.parse(await response.json());
}
/**
* Exchange a refresh token for an updated access token.
*
* Supports multiple client authentication methods as specified in OAuth 2.1:
* - Automatically selects the best authentication method based on server support
* - Preserves the original refresh token if a new one is not returned
*
* @param authorizationServerUrl - The authorization server's base URL
* @param options - Configuration object containing client info, refresh token, etc.
* @returns Promise resolving to OAuth tokens (preserves original refresh_token if not replaced)
* @throws {Error} When token refresh fails or authentication is invalid
*/
export async function refreshAuthorization(authorizationServerUrl, { metadata, clientInformation, refreshToken, resource, addClientAuthentication, fetchFn, }) {
var _a;
const grantType = "refresh_token";
let tokenUrl;
if (metadata) {
tokenUrl = new URL(metadata.token_endpoint);
if (metadata.grant_types_supported &&
!metadata.grant_types_supported.includes(grantType)) {
throw new Error(`Incompatible auth server: does not support grant type ${grantType}`);
}
}
else {
tokenUrl = new URL("/token", authorizationServerUrl);
}
// Exchange refresh token
const headers = new Headers({
"Content-Type": "application/x-www-form-urlencoded",
});
const params = new URLSearchParams({
grant_type: grantType,
refresh_token: refreshToken,
});
if (addClientAuthentication) {
addClientAuthentication(headers, params, authorizationServerUrl, metadata);
}
else {
// Determine and apply client authentication method
const supportedMethods = (_a = metadata === null || metadata === void 0 ? void 0 : metadata.token_endpoint_auth_methods_supported) !== null && _a !== void 0 ? _a : [];
const authMethod = selectClientAuthMethod(clientInformation, supportedMethods);
applyClientAuthentication(authMethod, clientInformation, headers, params);
}
if (resource) {
params.set("resource", resource.href);
}
const response = await (fetchFn !== null && fetchFn !== void 0 ? fetchFn : fetch)(tokenUrl, {
method: "POST",
headers,
body: params,
});
if (!response.ok) {
throw await parseErrorResponse(response);
}
return OAuthTokensSchema.parse({ refresh_token: refreshToken, ...(await response.json()) });
}
/**
* Performs OAuth 2.0 Dynamic Client Registration according to RFC 7591.
*/
export async function registerClient(authorizationServerUrl, { metadata, clientMetadata, fetchFn, }) {
let registrationUrl;
if (metadata) {
if (!metadata.registration_endpoint) {
throw new Error("Incompatible auth server: does not support dynamic client registration");
}
registrationUrl = new URL(metadata.registration_endpoint);
}
else {
registrationUrl = new URL("/register", authorizationServerUrl);
}
const response = await (fetchFn !== null && fetchFn !== void 0 ? fetchFn : fetch)(registrationUrl, {
method: "POST",
headers: {
"Content-Type": "application/json",
},
body: JSON.stringify(clientMetadata),
});
if (!response.ok) {
throw await parseErrorResponse(response);
}
return OAuthClientInformationFullSchema.parse(await response.json());
}
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