Email attachment with Google Drive and nodemailer

Question

I am trying to send an email attachment using the Drive API and nodemailer's mailComposer. I don't want to download the file from Google Drive so I'm doing this:

const attPDF = await drive.files.export(
    {
      fileId: "abcde123",
      mimeType: "application/pdf",
    },
    {
      responseType: "arrayBuffer",
    }
  );

Then I attach it to nodemailer like this:

const attachments = [
    {
      filename: "MyFile.pdf",
      content: new Buffer.from(attPDF.data),
      contentType: "application/pdf",
    },
  ];

The email gets sent successfully, including the attachment, but the attachment is a blank page. It'll follow the amount of pages the original file has but it'll all be blank. If the file has 2 pages it'll show 2 blank pages. Does anyone know how to fix it?

Answer 1

Recommendation:

I believe the exported PDF using arrayBuffer produces an empty file, because arrayBuffer processes files all at once and is limited to a specific length. This could result in a premature stoppage before the export finishes.

It is best to use stream for the response type to process files in chunks which makes sure that all segments are processed once the export finishes. Since this will be a PDF that you are attaching it has to be encoded in base64.

For exporting Google Workspace documents:

const attPDF = await drive.files.export(
    {
      fileId: "abcde123",
      mimeType: "application/pdf",
    },
    {
      responseType: "stream",
    }
  );

---

For attachments:

const attachments = [
    {
    filename: "MyFile.pdf",
    content: attPDF.data,
    encoding: "base64",
    contentType: "application/pdf",
    },
  ];

Reference:

• Reference on using stream as the response type in exporting file