如果您希望服务器能够代表用户调用 Google API 或能够在用户离线时调用 Google API,请按以下步骤操作。
准备工作
您必须完成基本 Google 登录集成。
为您的应用启用服务器端 API 访问
在在 iOS 应用中访问 Google API 页面上,您的应用仅在客户端对用户进行身份验证;在这种情况下,只有当用户正在使用您的应用时,您的应用才能访问 Google API。
通过本页介绍的过程,您的服务器可以在用户离线时代表用户调用 Google API。例如,照片应用可以通过在后端服务器上进行处理并将结果上传到另一个影集,对 Google 相册用户影集中的照片进行美化。为此,您的服务器需要一个访问令牌和一个刷新令牌。
若要为您的服务器获取访问令牌和刷新令牌,您可以请求一次性授权代码,您的服务器可使用该代码交换这两个令牌。成功登录后,您会看到一次性代码作为 GIDSignInResult
的 serverAuthCode
属性。
获取服务器客户端 ID,并在应用的
Info.plist
文件中在 OAuth 客户端 ID 下方指定该 ID(如果您尚未这样做)。<key>GIDServerClientID</key> <string>YOUR_SERVER_CLIENT_ID</string>
在登录回调中,检索一次性授权代码:
Swift
GIDSignIn.sharedInstance.signIn(withPresenting: self) { signInResult, error in guard error == nil else { return } guard let signInResult = signInResult else { return } let authCode = signInResult.serverAuthCode }
Objective-C
[GIDSignIn.sharedInstance signInWithPresentingViewController:self completion:^(GIDSignInResult * _Nullable signInResult, NSError * _Nullable error) { if (error) { return; } if (signInResult == nil) { return; } NSString *authCode = signInResult.serverAuthCode; }];
使用 HTTPS POST 将
serverAuthCode
字符串安全地传递到您的服务器。在应用的后端服务器上,用授权代码换取访问令牌和刷新令牌。使用访问令牌代表用户调用 Google API,并(可选)存储刷新令牌以在访问令牌到期时获取新的访问令牌。
例如:
Java
// (Receive authCode via HTTPS POST) if (request.getHeader("X-Requested-With") == null) { // Without the `X-Requested-With` header, this request could be forged. Aborts. } // Set path to the Web application client_secret_*.json file you downloaded from the // Google API Console: https://console.cloud.google.com/apis/credentials // You can also find your Web application client ID and client secret from the // console and specify them directly when you create the GoogleAuthorizationCodeTokenRequest // object. String CLIENT_SECRET_FILE = "/path/to/client_secret.json"; // Exchange auth code for access token GoogleClientSecrets clientSecrets = GoogleClientSecrets.load( JacksonFactory.getDefaultInstance(), new FileReader(CLIENT_SECRET_FILE)); GoogleTokenResponse tokenResponse = new GoogleAuthorizationCodeTokenRequest( new NetHttpTransport(), JacksonFactory.getDefaultInstance(), "https://oauth2.googleapis.com/token", clientSecrets.getDetails().getClientId(), clientSecrets.getDetails().getClientSecret(), authCode, REDIRECT_URI) // Specify the same redirect URI that you use with your web // app. If you don't have a web version of your app, you can // specify an empty string. .execute(); String accessToken = tokenResponse.getAccessToken(); // Use access token to call API GoogleCredential credential = new GoogleCredential().setAccessToken(accessToken); Drive drive = new Drive.Builder(new NetHttpTransport(), JacksonFactory.getDefaultInstance(), credential) .setApplicationName("Auth Code Exchange Demo") .build(); File file = drive.files().get("appfolder").execute(); // Get profile info from ID token GoogleIdToken idToken = tokenResponse.parseIdToken(); GoogleIdToken.Payload payload = idToken.getPayload(); String userId = payload.getSubject(); // Use this value as a key to identify a user. String email = payload.getEmail(); boolean emailVerified = Boolean.valueOf(payload.getEmailVerified()); String name = (String) payload.get("name"); String pictureUrl = (String) payload.get("picture"); String locale = (String) payload.get("locale"); String familyName = (String) payload.get("family_name"); String givenName = (String) payload.get("given_name");
Python
from apiclient import discovery import httplib2 from oauth2client import client # (Receive auth_code by HTTPS POST) # If this request does not have `X-Requested-With` header, this could be a CSRF if not request.headers.get('X-Requested-With'): abort(403) # Set path to the Web application client_secret_*.json file you downloaded from the # Google API Console: https://console.cloud.google.com/apis/credentials CLIENT_SECRET_FILE = '/path/to/client_secret.json' # Exchange auth code for access token, refresh token, and ID token credentials = client.credentials_from_clientsecrets_and_code( CLIENT_SECRET_FILE, ['https://www.googleapis.com/auth/drive.appdata', 'profile', 'email'], auth_code) # Call Google API http_auth = credentials.authorize(httplib2.Http()) drive_service = discovery.build('drive', 'v3', http=http_auth) appfolder = drive_service.files().get(fileId='appfolder').execute() # Get profile info from ID token userid = credentials.id_token['sub'] email = credentials.id_token['email']