如何解决Google Apps Script生成Gmail时模板格式丢失的问题

核心原因 #

• 现有代码调用Document.getText()仅提取纯文本内容，Google Doc中设置的所有格式会被直接剥离
• 调用GmailApp.createDraft()时仅传入了纯文本正文，未指定HTML格式的邮件内容，邮箱仅会渲染无格式文本

修改步骤 #

1. 新增Google Doc转HTML的工具方法 #

将Google Doc模板导出为HTML格式，保留所有原始格式（加粗、下划线、表格、段落样式等）

2. 调整占位符替换逻辑，适配HTML格式的模板 #

3. 修改邮件创建参数，传入HTML正文 #

完整修改后的代码 #

// What is the Google Document ID for your email template?
var googleDocId = "<my id>";
// Which column has the email address? Enter the column row header exactly.
var emailField = 'email';
// What is the subject line?
var emailSubject = 'Weekly Engagement Indicator';
// Which column is the indicator for email drafted? Enter the column row header exactly.
var emailStatus = 'date drafted';

/* ----------------------------------- */
// Be careful editing beyond this line //
/* ----------------------------------- */

var sheet = SpreadsheetApp.getActiveSheet(); // Use data from the active sheet

function draftMyEmails() {
  // 替换原有getText()，改为获取HTML格式的模板
  var emailTemplate = getDocAsHtml(googleDocId);
  var data = getCols(2, sheet.getLastRow() - 1);
  var myVars = getCols(1, 1)[0];
  var draftedRow = myVars.indexOf(emailStatus) + 1;

  // Work through each data row in the spreadsheet
  data.forEach(function(row, index){
    // Build a configuration for each row
    var config = createConfig(myVars, row);    
    
    // Prevent from drafing duplicates and from drafting emails without a recipient
    if (config[emailStatus] === '' && config[emailField]) {  
      // Replace template variables with the receipient's data
      var emailBodyHtml = replaceTemplateVars(emailTemplate, config);
      // 生成纯文本备用版本（不支持HTML的邮箱会显示这个）
      var emailBodyPlain = replaceTemplateVars(DocumentApp.openById(googleDocId).getText(), config);
      // Replace template variables in subject line
      var emailSubjectUpdated = replaceTemplateVars(emailSubject, config); 
      
      // Create the email draft，新增htmlBody参数
      GmailApp.createDraft(
        config[emailField],   // Recipient
        emailSubjectUpdated,  // Subject
        emailBodyPlain,       // 纯文本备用正文
        {
          htmlBody: emailBodyHtml // HTML格式正文
        }
      );
      
      sheet.getRange(2 + index, draftedRow).setValue(new Date()); // Update the last column
      SpreadsheetApp.flush(); // Make sure the last cell is updated right away
    }
  });
}

// 新增：将Google Doc导出为HTML格式
function getDocAsHtml(docId) {
  var url = "https://docs.google.com/feeds/download/documents/export/Export?id=" + docId + "&exportFormat=html";
  var param = {
    method: "get",
    headers: {"Authorization": "Bearer " + ScriptApp.getOAuthToken()},
    muteHttpExceptions: true,
  };
  var html = UrlFetchApp.fetch(url, param).getContentText();
  // 可选：清理Google Doc导出的冗余HTML代码，减少邮件体积
  html = html.replace(/<meta.*?>|<style.*?>[\s\S]*?<\/style>/g, "");
  return html;
}

function replaceTemplateVars(string, config) {
  return string.replace(/{[^{}]+}/g, function(key){
    return config[key.replace(/[{}]+/g, "")] || "";
  });
}

function createConfig(myVars, row) {
  return myVars.reduce(function(obj, myVar, index) {
    obj[myVar] = row[index];
    return obj;
  }, {});
}

function getCols(startRow, numRows) {
  var lastColumn = sheet.getLastColumn();      // Last column
  var dataRange = sheet.getRange(startRow, 1, numRows, lastColumn) // Fetch the data range of the active sheet
  return dataRange.getValues();            // Fetch values for each row in the range
}

注意事项 #

• 第一次运行修改后的代码时，会请求额外的Drive访问权限，同意授权即可
• 直接在Google Doc模板中设置所有你需要的格式（加粗、下划线、插入表格、调整字体颜色等），导出为HTML后都会自动保留
• 如果出现占位符替换失效的情况，检查模板中的占位符{xxx}是否为连续输入的无格式文本，不要给占位符本身单独设置格式即可解决

内容的提问来源于stack exchange，提问作者smcodemeister