React Native

Get IMAP Attachment Filenames

Demonstrates the Chilkat Imap.GetMailAttachFilename method, which returns the filename of an attachment. The first argument is the Email and the second is the zero-based attachment index. This example fetches only the message headers and lists the attachment filenames.

Background: This method reads the filename from ckx-imap-* metadata, so it works on a header-only email even though the attachment bodies have not been downloaded. That is exactly what a mail client needs to render the paperclip list — the names of the attached files — before the user decides to download any of them.

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import { Email, Imap } from '@chilkat/react-native'

async function chilkatExample() {
  // Demonstrates the Imap.GetMailAttachFilename method, which returns the filename of an
  // attachment.  The 1st argument is the Email and the 2nd is the zero-based attachment index.

  const imap = new Imap();

  imap.ssl = true;
  imap.port = 993;

  try {
    await imap.connectAsync('imap.example.com');
  } catch {
    console.log(imap.lastErrorText);
    return;
  }

  try {
    await imap.loginAsync('user@example.com', 'myPassword');
  } catch {
    console.log(imap.lastErrorText);
    return;
  }

  try {
    await imap.selectMailboxAsync('Inbox');
  } catch {
    console.log(imap.lastErrorText);
    return;
  }

  // Fetch only the message headers.  Attachment bodies are NOT downloaded, but the ckx-imap-*
  // metadata describing the attachments is present, so the attachment info methods still work.
  const headersOnly = true;
  const useUid = false;
  const seqNum = 1;
  const email = new Email();
  try {
    await imap.fetchEmailAsync(headersOnly, seqNum, useUid, email);
  } catch {
    console.log(imap.lastErrorText);
    return;
  }

  // Loop over the attachments and print each filename.
  const numAttach = imap.getMailNumAttach(email);
  console.log(`Attachments: ${numAttach}`);
  for (let i = 0; i < numAttach; i++) {
    // GetMailAttachFilename returns a string, so assign it to a string variable.
    let fname: string;
    try {
      fname = imap.getMailAttachFilename(email, i);
    } catch {
      console.log(imap.lastErrorText);
      return;
    }

    console.log(fname);
  }

  try {
    await imap.disconnectAsync();
  } catch {
    console.log(imap.lastErrorText);
    return;
  }
}