feat(auth): add support for access token subject type to Token Vault

EXAMPLES.md

@@ -152,10 +152,10 @@ const { data: tokens } = await auth.oauth.clientCredentialsGrant({
 });
 ```
 
-### Exchange a Refresh Token for an Access Token for a Connection
+### Exchange a Refresh or Access Token for an Access Token for a Connection
 
 ```js
-import { AuthenticationClient } from 'auth0';
+import { AuthenticationClient, SUBJECT_TOKEN_TYPES } from 'auth0';
 
 const auth = new AuthenticationClient({
   domain: '{YOUR_TENANT_AND REGION}.auth0.com',
@@ -165,6 +165,7 @@ const auth = new AuthenticationClient({
 
 const { data: token } = await auth.oauth.tokenForConnection({
   subject_token: '{refresh_token}',
+  subject_token_type: SUBJECT_TOKEN_TYPES.SUBJECT_TYPE_REFRESH_TOKEN, // Optional: defaults to refresh token type
   connection: 'google-oauth2', // The target social provider connection
   login_hint: 'user@example.com', // Optional: to target a specific account
 });

src/auth/oauth.ts

@@ -278,13 +278,17 @@ export interface TokenExchangeGrantRequest {
  */
 export interface TokenForConnectionRequest {
   /**
-   * The subject token(refresh token in this case) to exchange for an access token for a connection.
+   * The subject token to exchange for an access token for a connection.
    */
   subject_token: string;
   /**
    * The target social provider connection (e.g., "google-oauth2").
    */
   connection: string;
+  /**
+   * An optional subject token type parameter to pass to the authorization server. If not provided, it defaults to `urn:ietf:params:oauth:token-type:refresh_token`.
+   */
+  subject_token_type?: SUBJECT_TOKEN_TYPES;
   /**
    * Optional login hint
    */
@@ -299,9 +303,30 @@ export interface TokenForConnectionResponse {
   [key: string]: unknown;
 }
 
+export enum SUBJECT_TOKEN_TYPES {
+  /**
+   * Constant representing the subject type for a refresh token.
+   * This is used in OAuth 2.0 token exchange to specify that the token being exchanged is a refresh token.
+   *
+   * @see {@link https://tools.ietf.org/html/rfc8693#section-3.1 RFC 8693 Section 3.1}
+   */
+  SUBJECT_TYPE_REFRESH_TOKEN = 'urn:ietf:params:oauth:token-type:refresh_token',
+
+  /**
+   * Constant representing the subject type for a access token.
+   * This is used in OAuth 2.0 token exchange to specify that the token being exchanged is an access token.
+   *
+   * @see {@link https://tools.ietf.org/html/rfc8693#section-3.1 RFC 8693 Section 3.1}
+   */
+  SUBJECT_TYPE_ACCESS_TOKEN = 'urn:ietf:params:oauth:token-type:access_token',
+}
+
 export const TOKEN_FOR_CONNECTION_GRANT_TYPE =
   'urn:auth0:params:oauth:grant-type:token-exchange:federated-connection-access-token';
 
+/**
+ * @deprecated Use {@link SUBJECT_TOKEN_TYPES.SUBJECT_TYPE_REFRESH_TOKEN} instead.
+ */
 export const TOKEN_FOR_CONNECTION_TOKEN_TYPE = 'urn:ietf:params:oauth:token-type:refresh_token';
 export const TOKEN_FOR_CONNECTION_REQUESTED_TOKEN_TYPE =
   'http://auth0.com/oauth/token-type/federated-connection-access-token';
@@ -591,12 +616,13 @@ export class OAuth extends BaseAuthAPI {
   }
 
   /**
-   * Exchanges a subject token (refresh token in this case) for an access token for the connection.
+   * Exchanges a subject token for an access token for the connection.
    *
    * The request body includes:
    * - client_id (and client_secret/client_assertion via addClientAuthentication)
    * - grant_type set to `urn:auth0:params:oauth:grant-type:token-exchange:federated-connection-access-token`
-   * - subject_token (refresh token) and fixed subject_token_type for refresh tokens (`urn:ietf:params:oauth:token-type:refresh_token`)
+   * - subject_token: the token to exchange
+   * - subject_token_type: the type of token being exchanged. Defaults to refresh tokens (`urn:ietf:params:oauth:token-type:refresh_token`).
    * - requested_token_type (`http://auth0.com/oauth/token-type/federated-connection-access-token`) indicating that a federated connection access token is desired
    * - connection name and an optional `login_hint` if provided
    *
@@ -610,10 +636,16 @@ export class OAuth extends BaseAuthAPI {
   ): Promise<JSONApiResponse<TokenSet>> {
     validateRequiredRequestParams(bodyParameters, ['connection', 'subject_token']);
 
+    let subjectTokenType = SUBJECT_TOKEN_TYPES.SUBJECT_TYPE_REFRESH_TOKEN;
+
+    if (bodyParameters.subject_token_type) {
+      subjectTokenType = bodyParameters.subject_token_type;
+    }
+
     const body: Record<string, string> = {
       ...bodyParameters,
       grant_type: TOKEN_FOR_CONNECTION_GRANT_TYPE,
-      subject_token_type: TOKEN_FOR_CONNECTION_TOKEN_TYPE,
+      subject_token_type: subjectTokenType,
       requested_token_type: TOKEN_FOR_CONNECTION_REQUESTED_TOKEN_TYPE,
     };
 

test/auth/fixtures/oauth.json

@@ -213,5 +213,17 @@
       "expires_in": 86400,
       "token_type": "Bearer"
     }
+  },
+  {
+    "scope": "https://test-domain.auth0.com",
+    "method": "POST",
+    "path": "/oauth/token",
+    "body": "connection=google-oauth2&subject_token=test-id-token&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Aaccess_token&grant_type=urn%3Aauth0%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange%3Afederated-connection-access-token&requested_token_type=http%3A%2F%2Fauth0.com%2Foauth%2Ftoken-type%2Ffederated-connection-access-token&client_secret=test-client-secret",
+    "status": 200,
+    "response": {
+      "access_token": "connection-access-token",
+      "expires_in": 86400,
+      "token_type": "Bearer"
+    }
   }
 ]

test/auth/oauth.test.ts

@@ -9,6 +9,7 @@ import {
   RevokeRefreshTokenRequest,
   PushedAuthorizationRequest,
   TokenForConnectionRequest,
+  SUBJECT_TOKEN_TYPES,
 } from '../../src/index.js';
 import { withIdToken } from '../utils/index.js';
 
@@ -418,6 +419,23 @@ describe('OAuth', () => {
         },
       });
     });
+
+    it('should use subject_token_type when provided', async () => {
+      const oauth = new OAuth(opts);
+      await expect(
+        oauth.tokenForConnection({
+          connection: 'google-oauth2',
+          subject_token: 'test-id-token',
+          subject_token_type: SUBJECT_TOKEN_TYPES.SUBJECT_TYPE_ACCESS_TOKEN,
+        })
+      ).resolves.toMatchObject({
+        data: {
+          access_token: 'connection-access-token',
+          expires_in: 86400,
+          token_type: 'Bearer',
+        },
+      });
+    });
   });
 });