FirebaseCredential.java

/*
 * Copyright 2017 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.
 */

package com.google.firebase.auth;

import com.google.firebase.tasks.Task;

/**
 * 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 FirebaseCredentials}.
 */
public interface FirebaseCredential {

  /**
   * Returns a Google OAuth2 access token which can be used to authenticate with Firebase services.
   * This method does not cache tokens, and therefore each invocation will fetch a fresh token.
   * The caller is expected to implement caching by referencing the token expiry details
   * available in the returned GoogleOAuthAccessToken instance.
   *
   * @return A {@link Task} providing a Google OAuth access token.
   */
  Task<GoogleOAuthAccessToken> getAccessToken();
}