ウェブアプリは、Google API を安全に呼び出すため、アクセス トークンを取得する必要があります。
Google Identity Services JavaScript ライブラリは、ユーザー ログインの認証と、Google API で使用するアクセス トークン取得のための認可の両方をサポートしています。このライブラリはブラウザでの使用のみを目的としています。
認証はユーザーが誰であるかを確立するものであり、一般にユーザーの登録またはログインと呼ばれます。認可は、データまたはリソースへのアクセスを許可または拒否するプロセスです。ユーザーの同意の取得と管理、スコープで共有するデータやリソースの量の制限、Google API で使用するアクセス トークンの取得を行います。
gapi.auth2 モジュール、関連するオブジェクトとメソッドはバックグラウンドで自動的に読み込まれなくなり、より明示的な Google Identity Services ライブラリのオブジェクトとメソッドに置き換えられました。
ユーザーのセキュリティと意識を向上させるため、期限切れのアクセス トークンの自動更新が削除されました。アクセス トークンの有効期限が切れたら、アプリは Google API のエラー レスポンスを処理してリクエストを処理し、新しい有効なアクセス トークンを取得する必要があります。
認証時と認可時を明確に分離するため、アクセス トークンを発行しながら、アプリと Google アカウントに同時にユーザーをログインさせる機能はサポートされなくなりました。以前は、アクセス トークンをリクエストすると、ユーザーは Google アカウントにもログインし、ユーザー認証用の JWT ID トークン認証情報を返していました。
[null,null,["最終更新日 2023-12-01 UTC。"],[[["\u003cp\u003eGoogle Identity Services JavaScript library enables secure access to Google APIs via access tokens and supports user authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe library offers separate, streamlined user flows for sign-in (authentication) and consent (authorization) for enhanced user experience and control.\u003c/p\u003e\n"],["\u003cp\u003eDevelopers benefit from reduced complexity, improved security, and easier integration with features like a unified library for both implicit and authorization code flows.\u003c/p\u003e\n"],["\u003cp\u003eGoogle Identity Services prioritizes user privacy and security through measures like least privilege credentials and explicit access token refresh handling.\u003c/p\u003e\n"],["\u003cp\u003eThe library is exclusively for browser-based applications and should not be used with server-side JavaScript frameworks like Node.js.\u003c/p\u003e\n"]]],[],null,["# Authorizing for Web\n\nWeb apps must obtain an access token to securely call Google APIs.\n\nThe Google Identity Services JavaScript library supports both authentication for\nuser sign-in and authorization to obtain an access token for use with Google\nAPIs. The library is intended only for use in browsers.\n\nAuthentication establishes who someone is, and is commonly referred to as user\nsign-up or sign-in. Authorization is the process of granting or rejecting access\nto data or resources. It includes obtaining and managing user consent, limiting\nthe amount of data or resources shared with scopes, and retrieving an access\ntoken for use with Google APIs.\n\nThese guides cover authorization and data sharing topics.\n\n[How user authorization works](/identity/oauth2/web/guides/how-user-authz-works) describes the individual steps of user\nauthorization in detail and includes user dialog examples.\n\nIf you are looking for help with authentication and how to implement user\nsign-up and sign-in see [Sign In With Google](/identity/gsi/web/guides/overview).\n| **Note:** The `email`, `profile`, and `openid` scopes are used for user authentication. If your app only uses these scopes [Sign In With Google](/identity/gsi/web) is recommended instead.\n\nThis library is not intended for use with server-side JavaScript frameworks such\nas Node.js, instead use Google's [Node.js](https://github.com/googleapis/google-api-nodejs-client)\nclient library.\n\nWhat's changed\n--------------\n\nFor users, the Google Identity Services library offers numerous usability\nimprovements over earlier JavaScript libraries, including:\n\n- Authentication for user sign-in, and authorization to obtain an access token to call Google APIs, now have two separate and distinct user flows; one for [sign-in](/identity/gsi/web/guides/overview#how_it_works) and another for [consent](/identity/oauth2/web/guides/how-user-authz-works#user_consent) during authorization, with separate user flows to clearly differentiate who you are, from what an app can do.\n- Improved visibility and granular control of data sharing during [user\n consent](/identity/oauth2/web/guides/how-user-authz-works#user_consent).\n- Browser based pop-up dialogs to reduce friction, and which do not require users to leave your site to:\n - obtain an access token from Google, or\n - send an authorization code to your backend platform.\n\nFor developers, our focus has been to reduce complexity, improve security, and\nmake your integration as quick and easy as possible. Some of these changes are:\n\n- User [authentication](/identity/gsi/web/reference/js-reference) for sign-in, and [authorization](/identity/oauth2/web/reference/js-reference) used to obtain an access token to call Google APIs, are two separate and distinct sets of JavaScript objects, and methods. This reduces the complexity and amount of detail required to implement authentication or authorization.\n- A single JavaScript library now supports both the:\n - OAuth 2.0 implicit flow, used to obtain an access token for use in-browser\n - OAuth 2.0 authorization code flow, also known as offline access, and initiates securely delivering an authorization code to your backend platform, where it can be exchanged for an access token and refresh token. Previously, these flows were only available by using multiple libraries and through direct calls to OAuth 2.0 endpoints. A single library decreases your integration time and effort, instead of including and learning multiple libraries and OAuth 2.0 concepts you can focus on a single, unified interface.\n- Indirection through getter style functions has been removed for simplicity and readability.\n- When handling authorization responses you choose whether or not to use a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) to fulfill requests, instead of that decision being made for you.\n- The [Google API Client Library for JavaScript](https://github.com/google/google-api-javascript-client) has been updated with these changes:\n - the `gapi.auth2` module and associated objects and methods are no longer automatically loaded for you behind the scenes, and have been replaced with more explicit Google Identity Services library objects and methods.\n - Automatic refresh of expired access tokens has been removed to improve user security and awareness. After an access token expires your app must handle Google API error responses, request, and obtain a new, valid access token.\n - To support a clear separation of authentication and authorization moments, simultaneously signing a user in to your app and to their Google Account while also issuing an access token is no longer supported. Previously, requesting an access token also signed users into their Google Account and returned a JWT ID token credential for user authentication.\n- To increase user security and privacy, per user [credentials](/identity/oauth2/web/guides/migration-to-gis#example_credentials) issued for authorization follow the principle of least privilege by including only an access token and information required to manage it."]]
