Google Apps Script更新Gmail邮件字段失效及相关功能咨询

我正在尝试用Google Apps Script实现一个可更新邮件主题、正文、CC、BCC等字段的功能，但点击按钮后无任何更新效果，不确定问题出在代码本身还是appscript.json配置文件中。此外，还有两个疑问：

1. 该函数能否更新当前打开的Gmail撰写窗口，且变更无需刷新即可显示？
2. 是否存在特定函数、操作或API，可通过Google Add-ons、Gmail Add-ons或Gmail API以编程方式打开撰写窗口？

/**
 * Compose trigger function that fires when the compose UI is
 * requested. Builds and returns a compose UI for inserting images.
 *
 * @param {event} e The compose trigger event object. Not used in
 *         this example.
 * @return {Card[]}
 */
function startApp(e) {
  return [buildComposeCard()];
}

/**
 * Build a card to display interactive buttons to allow the user to
 * update the subject, and To, Cc, Bcc recipients.
 *
 * @return {Card}
 */
function buildComposeCard() {
  var card = CardService.newCardBuilder();
  var cardSection = CardService.newCardSection().setHeader('Update email');
  cardSection.addWidget(CardService.newTextButton().setText('Update email').setOnClickAction(CardService.newAction().setFunctionName('applyUpdateEmail')));
  return card.addSection(cardSection).build();
}

function applyUpdateEmail() {
  var subject = ['this is a subject'];
  var toRecipients = ['johhny.appleseed@gmail.com'];
  var ccRecipients = ['big.blue@montana.com'];
  var bccRecipients = ['spacer@gmail.com'];

  return CardService.newUpdateDraftActionResponseBuilder()
    .setUpdateDraftSubjectAction(CardService.newUpdateDraftSubjectAction().addUpdateSubject(subject))
    .setUpdateDraftToRecipientsAction(CardService.newUpdateDraftToRecipientsAction().addUpdateToRecipients(toRecipients))
    .setUpdateDraftCcRecipientsAction(CardService.newUpdateDraftCcRecipientsAction().addUpdateCcRecipients(ccRecipients))
    .setUpdateDraftBccRecipientsAction(CardService.newUpdateDraftBccRecipientsAction().addUpdateBccRecipients(bccRecipients))
    .build();
}

/**
 * Updates the subject field of the current email when the user clicks
 * on "Update subject" in the compose UI.
 *
 * Note: This is not the compose action that builds a compose UI, but
 * rather an action taken when the user interacts with the compose UI.
 *
 * @return {UpdateDraftActionResponse}
 */
function applyUpdateSubjectAction() {
  // Get the new subject field of the email.
  // This function is not shown in this example.
  var subject = ['this is a subject'];
  var response = CardService.newUpdateDraftActionResponseBuilder()
    .setUpdateDraftSubjectAction(CardService.newUpdateDraftSubjectAction()
      .addUpdateSubject(subject))
    .build();
  return response;
}

/**
 * Updates the To recipients of the current email when the user clicks
 * on "Update To recipients" in the compose UI.
 *
 * Note: This is not the compose action that builds a compose UI, but
 * rather an action taken when the user interacts with the compose UI.
 *
 * @return {UpdateDraftActionResponse}
 */
function applyUpdateToRecipientsAction() {
  // Get the new To recipients of the email.
  // This function is not shown in this example.
  var toRecipients = ['johhny.appleseed@gmail.com'];
  var response = CardService.newUpdateDraftActionResponseBuilder()
    .setUpdateDraftToRecipientsAction(CardService.newUpdateDraftToRecipientsAction()
      .addUpdateToRecipients(toRecipients))
    .build();
  return response;
}

/**
 * Updates the Cc recipients  of the current email when the user clicks
 * on "Update Cc recipients" in the compose UI.
 *
 * Note: This is not the compose action that builds a compose UI, but
 * rather an action taken when the user interacts with the compose UI.
 *
 * @return {UpdateDraftActionResponse}
 */
function applyUpdateCcRecipientsAction() {
  // Get the new Cc recipients of the email.
  // This function is not shown in this example.
  var ccRecipients = ['big.blue@montana.com'];
  var response = CardService.newUpdateDraftActionResponseBuilder()
    .setUpdateDraftCcRecipientsAction(CardService.newUpdateDraftCcRecipientsAction()
      .addUpdateCcRecipients(ccRecipients))
    .build();
  return response;
}

/**
 * Updates the Bcc recipients  of the current email when the user clicks
 * on "Update Bcc recipients" in the compose UI.
 *
 * Note: This is not the compose action that builds a compose UI, but
 * rather an action taken when the user interacts with the compose UI.
 *
 * @return {UpdateDraftActionResponse}
 */
function applyUpdateBccRecipientsAction() {
  // Get the new Bcc recipients of the email.
  // This function is not shown in this example.
  var bccRecipients = ['spacer@gmail.com'];
  var response = CardService.newUpdateDraftActionResponseBuilder()
    .setUpdateDraftBccRecipientsAction(CardService.newUpdateDraftBccRecipientsAction()
      .addUpdateBccRecipients(bccRecipients))
    .build();
  return response;
}

{
  "timeZone": "Asia/Kolkata",
  "dependencies": {},
  "exceptionLogging": "STACKDRIVER",
  "runtimeVersion": "V8",
  "oauthScopes": [
     "https://www.googleapis.com/auth/gmail.addons.current.action.compose",
    "https://www.googleapis.com/auth/gmail.addons.current.message.readonly",
    "https://www.googleapis.com/auth/gmail.addons.execute",
    "https://www.googleapis.com/auth/script.locale",
    "https://www.googleapis.com/auth/script.external_request",
    "https://www.googleapis.com/auth/gmail.readonly",
    "https://www.googleapis.com/auth/gmail.compose",
    "https://www.googleapis.com/auth/gmail.modify",
    "https://mail.google.com/", 
    "https://www.googleapis.com/auth/gmail.addons.current.message.metadata",
    "https://www.googleapis.com/auth/userinfo.email"
  ],
  "addOns": {
    "common": {
      "name": "Example 1",
      "logoUrl": "https://www.gstatic.com/images/branding/product/2x/contacts_48dp.png",
      "useLocaleFromApp": true,
      "homepageTrigger": {
        "runFunction": "startApp",
        "enabled": true
      },
      "universalActions": [
        {
          "label": "Google",
          "openLink": "www.google.com"
        }
      ]
    },
    "gmail": {
      "contextualTriggers": [
        {
          "unconditional": {},
          "onTriggerFunction": "startApp"
        }
      ],
      "composeTrigger": {
        "selectActions": [
          {
            "text": "Login",
            "runFunction": "startApp"
          }
        ],
        "draftAccess": "METADATA"
      }
    }
  }
}

1. 点击按钮无更新的原因及修复 #

配置文件问题 #

appscript.json中composeTrigger.draftAccess设置为METADATA，该权限仅允许读取草稿元数据，无法修改草稿内容。需改为WRITE权限：

"composeTrigger": {
  "selectActions": [
    {
      "text": "Login",
      "runFunction": "startApp"
    }
  ],
  "draftAccess": "WRITE"
}

代码逻辑问题 #

• addUpdateSubject方法接收的是单个字符串，而非数组。当前传的是['this is a subject']，需改为直接传字符串：

  .setUpdateDraftSubjectAction(CardService.newUpdateDraftSubjectAction().addUpdateSubject('this is a subject'))
  

• 收件人更新方法：addUpdateToRecipients/addUpdateCcRecipients/addUpdateBccRecipients每次只能添加单个收件人，若要设置多个收件人，应使用setUpdateToRecipients/setUpdateCcRecipients/setUpdateBccRecipients并传入数组：

  function applyUpdateEmail() {
    var subject = 'this is a subject';
    var toRecipients = ['johhny.appleseed@gmail.com'];
    var ccRecipients = ['big.blue@montana.com'];
    var bccRecipients = ['spacer@gmail.com'];
  
    return CardService.newUpdateDraftActionResponseBuilder()
      .setUpdateDraftSubjectAction(CardService.newUpdateDraftSubjectAction().addUpdateSubject(subject))
      .setUpdateDraftToRecipientsAction(CardService.newUpdateDraftToRecipientsAction().setUpdateToRecipients(toRecipients))
      .setUpdateDraftCcRecipientsAction(CardService.newUpdateDraftCcRecipientsAction().setUpdateCcRecipients(ccRecipients))
      .setUpdateDraftBccRecipientsAction(CardService.newUpdateDraftBccRecipientsAction().setUpdateBccRecipients(bccRecipients))
      .build();
  }
  

2. 疑问解答 #

疑问1：能否更新当前打开的撰写窗口且无需刷新？ #

可以。使用CardService.newUpdateDraftActionResponseBuilder()构建的响应，专门用于实时更新当前打开的Gmail撰写窗口，修改内容会立即显示，无需刷新页面。修正上述代码和配置后即可实现该效果。

疑问2：如何编程打开撰写窗口？ #

有两种常用方式：

• Gmail Add-ons方式：使用CardService.newComposeActionResponseBuilder()构建响应，可直接打开新的撰写窗口，并预设主题、收件人、正文等内容：

  function openComposeWindow() {
    return CardService.newComposeActionResponseBuilder()
      .setToRecipients(['example@test.com'])
      .setSubject('预设主题')
      .setBody('预设正文内容')
      .build();
  }
  

• Gmail API方式：调用users.drafts.create接口创建草稿，再通过草稿的id生成打开链接；或者直接构造Gmail撰写URL，通过链接打开撰写窗口。

内容的提问来源于stack exchange，提问作者Harsh