Allow Credential to auto-generate typings, separate internal vs external APIs (#1012)

Author: MathBunny

gulpfile.js

@@ -54,6 +54,7 @@ var paths = {
 
   curatedTypings: [
     'src/*.d.ts',
+    '!src/credential.d.ts',
     '!src/database.d.ts',
     '!src/instance-id.d.ts',
     '!src/security-rules.d.ts',

src/auth/token-generator.ts

@@ -15,7 +15,7 @@
  */
 
 import { FirebaseApp } from '../firebase-app';
-import { ServiceAccountCredential } from '../credential/credential';
+import { ServiceAccountCredential } from '../credential/credential-internal';
 import { AuthClientErrorCode, FirebaseAuthError } from '../utils/error';
 import { AuthorizedHttpClient, HttpError, HttpRequestConfig, HttpClient } from '../utils/api-request';
 

src/credential/credential-interfaces.ts

@@ -0,0 +1,50 @@
+/*!
+ * Copyright 2020 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// TODO: According to the typings this is part of the Firebase Namespace today
+// and not credential; it will need to be moved accordingly.
+/**
+ * Interface for Google OAuth 2.0 access tokens.
+ */
+export interface GoogleOAuthAccessToken {
+  /* tslint:disable:variable-name */
+  access_token: string;
+  expires_in: number;
+  /* tslint:enable:variable-name */
+}
+
+/**
+ * Interface that provides Google OAuth2 access tokens used to authenticate
+ * with Firebase services.
+ *
+ * In most cases, you will not need to implement this yourself and can instead
+ * use the default implementations provided by
+ * {@link admin.credential `admin.credential`}.
+ */
+export interface Credential {
+  /**
+   * Returns a Google OAuth2 access token object used to authenticate with
+   * Firebase services.
+   *
+   * This object contains the following properties:
+   * * `access_token` (`string`): The actual Google OAuth2 access token.
+   * * `expires_in` (`number`): The number of seconds from when the token was
+   *   issued that it expires.
+   *
+   * @return A Google OAuth2 access token object.
+   */
+  getAccessToken(): Promise<GoogleOAuthAccessToken>;
+}