如何使用 Gmail API、OAuth2 for Apps 脚本和域范围委派为 G Suite 域中的用户设置电子邮件签名

Question

这是我之前发布的问题/答案 (How to use the Google Email Settings API and the OAuth2 for Apps Script Library to set email signatures for users in a Google Apps domain) 的后续，但我正在创建一个新问题，因为 Email Settings API 已被弃用，并且现在该过程有很大不同。

作为 G Suite 域的管理员，您如何使用 Gmail API 通过 Google Apps 脚本以编程方式设置域中用户的电子邮件签名？

Answer 1

此方法使用 Gmail API、OAuth2 for Apps 脚本库和“域范围的授权”，这是 G Suite 管理员代表其域内的用户进行 API 调用的一种方式。

第 1 步：确保将 OAuth2 For Apps Script 库添加到您的项目中。

第 2 步： 设置“域范围的授权”。有一个页面here 解释了如何为 Drive API 执行此操作，但对于任何 Google API（包括 Gmail API）来说几乎都是一样的。按照该页面上的步骤直至（包括）“将域范围的权限委派给您的服务帐户”步骤。

第三步：下面的代码包含了在前面的步骤完成后如何设置签名：

function setSignatureTest() {

  var email = 'test@test.com';

  var signature = 'test signature';

  var test = setSignature(email, signature);

  Logger.log('test result: ' + test);

}


function setSignature(email, signature) {

  Logger.log('starting setSignature');

  var signatureSetSuccessfully = false;

  var service = getDomainWideDelegationService('Gmail: ', 'https://www.googleapis.com/auth/gmail.settings.basic', email);

  if (!service.hasAccess()) {

    Logger.log('failed to authenticate as user ' + email);

    Logger.log(service.getLastError());

    signatureSetSuccessfully = service.getLastError();

    return signatureSetSuccessfully;

  } else Logger.log('successfully authenticated as user ' + email);

  var username = email.split("@")[0];

  var resource = { signature: signature };

  var requestBody                = {};
  requestBody.headers            = {'Authorization': 'Bearer ' + service.getAccessToken()};
  requestBody.contentType        = "application/json";
  requestBody.method             = "PUT";
  requestBody.payload            = JSON.stringify(resource);
  requestBody.muteHttpExceptions = false;

  var emailForUrl = encodeURIComponent(email);

  var url = 'https://www.googleapis.com/gmail/v1/users/me/settings/sendAs/' + emailForUrl;

  var maxSetSignatureAttempts     = 20;
  var currentSetSignatureAttempts = 0;

  do {

    try {

      currentSetSignatureAttempts++;

      Logger.log('currentSetSignatureAttempts: ' + currentSetSignatureAttempts);

      var setSignatureResponse = UrlFetchApp.fetch(url, requestBody);

      Logger.log('setSignatureResponse on successful attempt:' + setSignatureResponse);

      signatureSetSuccessfully = true;

      break;

    } catch(e) {

      Logger.log('set signature failed attempt, waiting 3 seconds and re-trying');

      Utilities.sleep(3000);

    }

    if (currentSetSignatureAttempts >= maxSetSignatureAttempts) {

      Logger.log('exceeded ' + maxSetSignatureAttempts + ' set signature attempts, deleting user and ending script');

      throw new Error('Something went wrong when setting their email signature.');

    }

  } while (!signatureSetSuccessfully);

  return signatureSetSuccessfully;

}

// these two things are included in the .JSON file that you download when creating the service account and service account key
var OAUTH2_SERVICE_ACCOUNT_PRIVATE_KEY  = '-----BEGIN PRIVATE KEY-----\nxxxxxxxxxxxxxxxxxxxxx\n-----END PRIVATE KEY-----\n';
var OAUTH2_SERVICE_ACCOUNT_CLIENT_EMAIL = 'xxxxxxxxxxxxxxxxxxxxx.iam.gserviceaccount.com';


function getDomainWideDelegationService(serviceName, scope, email) {

  Logger.log('starting getDomainWideDelegationService for email: ' + email);

  return OAuth2.createService(serviceName + email)
      // Set the endpoint URL.
      .setTokenUrl('https://accounts.google.com/o/oauth2/token')

      // Set the private key and issuer.
      .setPrivateKey(OAUTH2_SERVICE_ACCOUNT_PRIVATE_KEY)
      .setIssuer(OAUTH2_SERVICE_ACCOUNT_CLIENT_EMAIL)

      // Set the name of the user to impersonate. This will only work for
      // Google Apps for Work/EDU accounts whose admin has setup domain-wide
      // delegation:
      // https://developers.google.com/identity/protocols/OAuth2ServiceAccount#delegatingauthority
      .setSubject(email)

      // Set the property store where authorized tokens should be persisted.
      .setPropertyStore(PropertiesService.getScriptProperties())

      // Set the scope. This must match one of the scopes configured during the
      // setup of domain-wide delegation.
      .setScope(scope);

}

请注意：带有maxSetSignatureAttempts 和currentSetSignatureAttempts 变量的do-while 循环不是必需的。我添加它是因为如果您在创建 Google 帐户并分配 G Suite 许可证后立即尝试设置签名，有时 Gmail API 会返回错误，就好像尚未创建用户一样。如果出现错误，该 do-while 循环基本上会等待 3 秒，然后再试一次，最多 x 次。如果您为现有用户设置签名，则不应该有这个问题。另外，本来我只是固定的 10 秒睡眠，但大多数时候它不需要花那么长时间，但其他时候它仍然会失败。所以这个循环比固定的睡眠量要好。