Google Apps Script that saves Gmail messages from a specific sender into a Google Doc. It supports optional date filters, attachment saving to Google Drive, and prevents duplicates by labeling threads once processed.

save-emails-to-doc.gs

/**
 * Save emails from a specific sender to a Google Doc (thread-level dedupe).
 * - Uses a Gmail label on the THREAD to avoid duplicates on subsequent runs.
 * - Optionally saves attachments to Drive and links them in the Doc.
 *
 * Scopes prompted on first run:
 * GmailApp, DocumentApp, DriveApp (if INCLUDE_ATTACHMENTS = true)
 */

/* ========================== CONFIG ========================== */
const CONFIG = {
  SENDER_EMAIL: '[email protected]',                 // REQUIRED
  DOC_NAME: 'Saved Emails — [email protected]',      // Created if missing
  AFTER: '2025/01/01',                                 // 'YYYY/MM/DD' or '' to disable
  BEFORE: '',                                          // 'YYYY/MM/DD' or '' to disable
  EXTRA_QUERY: '',                                     // e.g., 'has:attachment -in:drafts'
  MAX_THREADS: 150,                                    // safety cap per run
  INCLUDE_ATTACHMENTS: false,                          // save attachments & link them
  ATTACHMENTS_FOLDER_NAME: 'Email Attachments — [email protected]',
  DEDUP_LABEL_NAME: 'SavedToDoc',                      // label used on THREADS
};
/* ============================================================ */

/**
 * Entry point.
 */
function runSaveEmailsToDoc() {
  const docId = ensureDocExists_(CONFIG.DOC_NAME);
  const dedupLabel = ensureLabel_(CONFIG.DEDUP_LABEL_NAME);
  const attachmentsFolder = CONFIG.INCLUDE_ATTACHMENTS
    ? ensureFolder_(CONFIG.ATTACHMENTS_FOLDER_NAME)
    : null;

  const query = buildQuery_({
    from: CONFIG.SENDER_EMAIL,
    after: CONFIG.AFTER,
    before: CONFIG.BEFORE,
    extra: CONFIG.EXTRA_QUERY,
    // NOTE: Exclude threads already labeled
    excludeLabel: CONFIG.DEDUP_LABEL_NAME,
  });

  const threads = GmailApp.search(query, 0, CONFIG.MAX_THREADS);
  if (!threads.length) {
    logToDoc_(docId, `No new threads found for query:\n${query}`);
    return;
  }

  const doc = DocumentApp.openById(docId);
  const body = doc.getBody();

  // newest-first to keep doc reading top→bottom chronologically across runs
  threads.forEach((thread) => {
    // Safety: skip if somehow already labeled
    const threadHasLabel = thread.getLabels().some(l => l.getName() === CONFIG.DEDUP_LABEL_NAME);
    if (threadHasLabel) return;

    const messages = thread.getMessages();
    messages.forEach((msg) => {
      appendMessageToDoc_(body, msg, {
        includeAttachments: CONFIG.INCLUDE_ATTACHMENTS,
        attachmentsFolder,
      });
      Utilities.sleep(30); // gentle on quotas for large exports
    });

    // Mark the whole thread as saved
    thread.addLabel(dedupLabel);
    Utilities.sleep(50);
  });

  doc.saveAndClose();
}

/* ======================== HELPERS =========================== */

function buildQuery_({ from, after, before, extra, excludeLabel }) {
  const parts = [];
  if (from) parts.push(`from:${quoteGmail_(from)}`);
  if (after) parts.push(`after:${quoteGmail_(after)}`);
  if (before) parts.push(`before:${quoteGmail_(before)}`);
  if (extra) parts.push(extra.trim());
  if (excludeLabel) parts.push(`-label:${quoteGmail_(excludeLabel)}`);
  parts.push('-in:drafts -in:spam -in:trash');
  return parts.filter(Boolean).join(' ');
}

function quoteGmail_(val) {
  return /[\s:"']/g.test(val) ? `"${val.replace(/"/g, '\\"')}"` : val;
}

function ensureDocExists_(name) {
  const files = DriveApp.getFilesByName(name);
  if (files.hasNext()) return files.next().getId();

  const doc = DocumentApp.create(name);
  const body = doc.getBody();
  body.appendParagraph(name).setHeading(DocumentApp.ParagraphHeading.TITLE);
  body.appendHorizontalRule();
  doc.saveAndClose();
  return doc.getId();
}

function ensureLabel_(name) {
  return GmailApp.getUserLabelByName(name) || GmailApp.createLabel(name);
}

function ensureFolder_(name) {
  const iter = DriveApp.getFoldersByName(name);
  return iter.hasNext() ? iter.next() : DriveApp.createFolder(name);
}

function appendMessageToDoc_(body, msg, opts) {
  const subject = msg.getSubject() || '(no subject)';
  const from = msg.getFrom();
  const to = msg.getTo() || '';
  const cc = msg.getCc() || '';
  const date = msg.getDate();
  const permalink = 'https://mail.google.com/mail/u/0/#all/' + msg.getId();

  const header = [
    ['Subject', subject],
    ['From', from],
    ['To', to],
  ];
  if (cc) header.push(['Cc', cc]);
  header.push(['Date', Utilities.formatDate(date, Session.getScriptTimeZone(), 'yyyy-MM-dd HH:mm:ss Z')]);
  header.push(['Gmail Link', permalink]);

  const table = body.appendTable(header);
  table.setBorderWidth(0.5);

  for (let r = 0; r < table.getNumRows(); r++) {
    table.getRow(r).getCell(0).editAsText().setBold(true);
  }

  body.appendParagraph('').setSpacingAfter(0);

  const plain = (msg.getPlainBody && msg.getPlainBody()) || '';
  if (plain.trim()) {
    body.appendParagraph('Message:').setHeading(DocumentApp.ParagraphHeading.HEADING4);
    body.appendParagraph(plain);
  } else {
    // Fallback if only HTML
    const html = (msg.getBody && msg.getBody()) || '';
    body.appendParagraph('Message (HTML, simplified):').setHeading(DocumentApp.ParagraphHeading.HEADING4);
    body.appendParagraph(stripHtml_(html));
  }

  if (opts && opts.includeAttachments) {
    const attachments = msg.getAttachments({ includeInlineImages: false, includeAttachments: true }) || [];
    if (attachments.length && opts.attachmentsFolder) {
      body.appendParagraph('').setSpacingAfter(0);
      body.appendParagraph('Attachments:').setHeading(DocumentApp.ParagraphHeading.HEADING4);
      attachments.forEach((blob) => {
        const file = opts.attachmentsFolder.createFile(blob);
        body.appendParagraph(`${file.getName()} — ${file.getUrl()}`);
      });
    }
  }

  body.appendHorizontalRule();
}

function stripHtml_(html) {
  // very light cleanup; Docs will render it as text
  return html
    .replace(/<br\s*\/?>/gi, '\n')
    .replace(/<\/p>/gi, '\n\n')
    .replace(/<style[\s\S]*?<\/style>/gi, '')
    .replace(/<script[\s\S]*?<\/script>/gi, '')
    .replace(/<[^>]+>/g, '')
    .replace(/&nbsp;/g, ' ')
    .replace(/&amp;/g, '&')
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>');
}

function logToDoc_(docId, message) {
  const doc = DocumentApp.openById(docId);
  doc.getBody().appendParagraph(`[${new Date().toISOString()}] ${message}`);
  doc.saveAndClose();
}