使用 OAuth 进行 Google 帐号关联

使用集合让一切井井有条 根据您的偏好保存内容并对其进行分类。

帐号使用行业标准的 OAuth 2.0 隐式授权代码流程来关联。您的服务必须支持符合 OAuth 2.0 规范的授权令牌交换端点。

In the implicit flow, Google opens your authorization endpoint in the user's browser. After successful sign in, you return a long-lived access token to Google. This access token is now included in every request sent from Google.

In the authorization code flow, you need two endpoints:

  • The authorization endpoint, which presents the sign-in UI to your users that aren't already signed in. The authorization endpoint also creates a short-lived authorization code to record users' consent to the requested access.

  • The token exchange endpoint, which is responsible for two types of exchanges:

    1. Exchanges an authorization code for a long-lived refresh token and a short-lived access token. This exchange happens when the user goes through the account linking flow.
    2. Exchanges a long-lived refresh token for a short-lived access token. This exchange happens when Google needs a new access token because the one it had expired.

Choose an OAuth 2.0 flow

Although the implicit flow is simpler to implement, Google recommends that access tokens issued by the implicit flow never expire. This is because the user is forced to link their account again after a token expires with the implicit flow. If you need token expiration for security reasons, we strongly recommend that you use the authorization code flow instead.

Design guidelines

This section describes the design requirements and recommendations for the user screen that you host for OAuth linking flows. After it's called by Google's app, your platform displays a sign in to Google page and account linking consent screen to the user. The user is directed back to Google's app after giving their consent to link accounts.

This figure shows the steps for a user to link their Google account
            to your authentication system. The first screenshot shows
            user-initiated linking from your platform. The second image shows
            user sign-in to Google, while the third shows the user consent and
            confirmation for linking their Google account with your app. The
            final screenshot shows a successfully linked user account in the
            Google app.
Figure 1. Account linking user sign in to Google and consent screens.

Requirements

  1. You must communicate that the user’s account will be linked to Google, not a specific Google product like Google Home or Google Assistant.

Recommendations

We recommend that you do the following:

  1. Display Google's Privacy Policy. Include a link to Google’s Privacy Policy on the consent screen.

  2. Data to be shared. Use clear and concise language to tell the user what data of theirs Google requires and why.

  3. Clear call-to-action. State a clear call-to-action on your consent screen, such as “Agree and link.” This is because users need to understand what data they're required to share with Google to link their accounts.

  4. Ability to cancel. Provide a way for users to go back or cancel, if they choose not to link.

  5. Clear sign-in process. Ensure that users have clear method for signing in to their Google account, such as fields for their username and password or Sign in with Google.

  6. Ability to unlink. Offer a mechanism for users to unlink, such as a URL to their account settings on your platform. Alternatively, you can include a link to Google Account where users can manage their linked account.

  7. Ability to change user account. Suggest a method for users to switch their account(s). This is especially beneficial if users tend to have multiple accounts.

    • If a user must close the consent screen to switch accounts, send a recoverable error to Google so the user can sign in to the desired account with OAuth linking and the implicit flow.
  8. Include your logo. Display your company logo on the consent screen. Use your style guidelines to place your logo. If you wish to also display Google's logo, see Logos and trademarks.

创建项目

如需创建项目以使用帐号关联,请执行以下操作:

  1. Go to the Google API Console.
  2. 单击创建项目
  3. 输入名称或接受生成的建议。
  4. 确认或编辑所有剩余字段。
  5. 点击创建

要查看您的项目ID:

  1. Go to the Google API Console.
  2. 在登录页面的表格中找到您的项目。项目ID出现在ID列中。

Google 帐号关联流程包括一个同意屏幕,其中向用户说明应用请求访问其数据的权限、请求获取的数据类型以及适用的条款。您需要先配置 OAuth 同意屏幕,然后才能生成 Google API 客户端 ID。

  1. 打开 Google API 控制台的 OAuth 同意屏幕页面。
  2. 如果出现提示,请选择您刚刚创建的项目。
  3. 在“OAuth 同意屏幕”页面上,填写表单,然后点击“保存”按钮。

    应用名称:征求用户同意的应用的名称。名称应准确反映您的应用,并且与用户看到的应用名称一致。应用名称将显示在帐号关联同意屏幕上。

    应用徽标:同意屏幕上的图片,有助于用户识别您的应用。徽标显示在帐号关联同意屏幕和帐号设置

    支持电子邮件地址:用户与您联系,询问有关其意见征求方面的问题。

    Google API 的范围:范围允许您的应用访问用户的私人 Google 数据。对于 Google 帐号关联用例,默认范围(电子邮件地址、个人资料、OpenID)就足够了,您无需添加任何敏感范围。一般来说,最佳做法是在需要访问权限时逐步请求范围,而不是预先请求。了解详情

    已获授权的网域:为了保护您和您的用户,Google 只允许使用 OAuth 进行身份验证的应用使用已获授权的网域。您的申请链接必须托管在已获授权的网域上。了解详情

    应用首页链接:您的应用的首页。必须托管在已获授权的网域上。

    应用隐私权政策链接:显示在 Google 帐号链接意见征求屏幕上。必须托管在已获授权的网域上。

    应用服务条款链接(可选):必须托管在已获授权的网域上。

    图 1. 虚构应用 Tunery 的 Google 帐号关联同意屏幕

  4. 查看“验证状态”,如果您的应用需要验证,请点击“提交验证”按钮,提交您的申请以供验证。如需了解详情,请参阅 OAuth 验证要求

实现 OAuth 服务器

To support the OAuth 2.0 implicit flow, your service makes an authorization endpoint available by HTTPS. This endpoint is responsible for authentication and obtaining consent from users for data access. The authorization endpoint presents a sign-in UI to your users that aren't already signed in and records consent to the requested access.

When a Google application needs to call one of your service's authorized APIs, Google uses this endpoint to get permission from your users to call these APIs on their behalf.

A typical OAuth 2.0 implicit flow session initiated by Google has the following flow:

  1. Google opens your authorization endpoint in the user's browser. The user signs in, if not signed in already, and grants Google permission to access their data with your API, if they haven't already granted permission.
  2. Your service creates an access token and returns it to Google. To do so, redirect the user's browser back to Google with the access token attached to the request.
  3. Google calls your service's APIs and attaches the access token with each request. Your service verifies that the access token grants Google authorization to access the API and then completes the API call.

Handle authorization requests

When a Google application needs to perform account linking via an OAuth 2.0 implicit flow, Google sends the user to your authorization endpoint with a request that includes the following parameters:

Authorization endpoint parameters
client_id The client ID you assigned to Google.
redirect_uri The URL to which you send the response to this request.
state A bookkeeping value that is passed back to Google unchanged in the redirect URI.
response_type The type of value to return in the response. For the OAuth 2.0 implicit flow, the response type is always token.
user_locale The Google Account language setting in RFC5646 format used to localize your content in the user's preferred language.

For example, if your authorization endpoint is available at https://myservice.example.com/auth, a request might look like the following:

GET https://myservice.example.com/auth?client_id=GOOGLE_CLIENT_ID&redirect_uri=REDIRECT_URI&state=STATE_STRING&response_type=token&user_locale=LOCALE

For your authorization endpoint to handle sign-in requests, do the following steps:

  1. Verify the client_id and redirect_uri values to prevent granting access to unintended or misconfigured client apps:

    • Confirm that the client_id matches the client ID you assigned to Google.
    • Confirm that the URL specified by the redirect_uri parameter has the following form:
      https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID
      https://oauth-redirect-sandbox.googleusercontent.com/r/YOUR_PROJECT_ID
      
  2. Check if the user is signed in to your service. If the user isn't signed in, complete your service's sign-in or sign-up flow.

  3. Generate an access token for Google to use to access your API. The access token can be any string value, but it must uniquely represent the user and the client the token is for and must not be guessable.

  4. Send an HTTP response that redirects the user's browser to the URL specified by the redirect_uri parameter. Include all of the following parameters in the URL fragment:

    • access_token: The access token you just generated
    • token_type: The string bearer
    • state: The unmodified state value from the original request

    The following is an example of the resulting URL:

    https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID#access_token=ACCESS_TOKEN&token_type=bearer&state=STATE_STRING

Google's OAuth 2.0 redirect handler receives the access token and confirms that the state value hasn't changed. After Google has obtained an access token for your service, Google attaches the token to subsequent calls to your service APIs.

处理用户信息请求

用户信息终端是一个OAuth 2.0保护的资源,对链接的用户返回的权利要求。实现和托管 userinfo 端点是可选的,以下用例除外:

从您的令牌端点成功检索访问令牌后,Google 会向您的 userinfo 端点发送请求,以检索有关链接用户的基本个人资料信息。

userinfo 端点请求标头
Authorization header Bearer 类型的访问令牌。

例如,如果你的用户信息终端可在https://myservice.example.com/userinfo ,请求看起来像下面这样:

GET /userinfo HTTP/1.1
Host: myservice.example.com
Authorization: Bearer ACCESS_TOKEN

要让您的 userinfo 端点处理请求,请执行以下步骤:

  1. 从 Authorization 标头中提取访问令牌并返回与访问令牌关联的用户的信息。
  2. 如果访问令牌无效,返回HTTP 401错误未经授权使用的WWW-Authenticate响应头。下面是一个userinfo的错误响应的一个示例:
    HTTP/1.1 401 Unauthorized
    WWW-Authenticate: error="invalid_token",
    error_description="The Access Token expired"
    
    如果一个401未经授权,或任何其它不成功错误响应在关联过程返回时,误差将是不可恢复的,所检索的令牌将被丢弃,并且用户将必须再次启动链接过程。
  3. 如果访问令牌是有效的,回国与以下JSON对象在HTTPS响应的身体HTTP 200回应:

    {
    "sub": "USER_UUID",
    "email": "EMAIL_ADDRESS",
    "given_name": "FIRST_NAME",
    "family_name": "LAST_NAME",
    "name": "FULL_NAME",
    "picture": "PROFILE_PICTURE",
    }
    
    如果你的用户信息端点返回一个HTTP 200成功响应,检索到的令牌和索赔登记针对用户的谷歌帐户。

    用户信息端点响应
    sub标识系统中用户的唯一 ID。
    email用户的电子邮件地址。
    given_name可选:用户的名字。
    family_name可选:用户的姓氏。
    name可选:用户的全名。
    picture可选:用户的档案图片。

验证您的实现

您可以通过使用验证实现的OAuth 2.0游乐场工具。

在工具中,执行以下步骤:

  1. 单击配置打开的OAuth 2.0配置窗口。
  2. OAuth流场中,选择客户端
  3. OAuth端点字段中,选择自定义
  4. 在相应字段中指定您的 OAuth 2.0 端点和您分配给 Google 的客户端 ID。
  5. 步骤1部分,不要选择任何谷歌范围。相反,将此字段留空或键入对您的服务器有效的范围(如果不使用 OAuth 范围,则输入任意字符串)。当您完成后,单击授权的API。
  6. 步骤2步骤3段,完成OAuth 2.0流程和验证每个步骤按预期工作。

您可以通过验证您的实现谷歌帐户链接演示工具。

在工具中,执行以下步骤:

  1. 点击登录在与谷歌按钮。
  2. 选择您要关联的帐户。
  3. 输入服务标识。
  4. (可选)输入您将请求访问的一个或多个范围。
  5. 单击开始演示
  6. 出现提示时,确认您可以同意并拒绝链接请求。
  7. 确认您被重定向到您的平台。