Nodejs send stream via email

Question

I'm trying to send my stream data via email using Nodemailer but for some reason, the attachment is coming up as 0 kb when I download it and look at its info. How can I properly send the stream & it's data as an attachment? The stream should contain a PKPass is it a better option to send the response as an attachment? I'm using passkit-generator to generate the PKPass

const stream = examplePass.generate();

res.set({
    'Content-Type': 'application/vnd.apple.pkpass',
    'Content-disposition': `attachment; filename=${passName}.pkpass`,
});

stream.pipe(res);

//Send the receipt email

stream.on('finish', (attach) => {

    let transporter = nodemailer.createTransport({
        host: 'smtp.gmail.com',
        port: 587,
        secure: false,
        requireTLS: true,
        auth: {
            user: '[email protected]',
            pass: 'password',
        },
    });

    let mailOptions = {
        from: '[email protected]',
        to: '[email protected]',
        subject: 'You\'re on your way to ',
        html: '<h1>Reciept email</h1>',
        attachments: [
            {
                filename: 'Event.pkpass',
                contentType: 'application/vnd.apple.pkpass',
                content: stream,
            },
        ],
    };

    transporter.sendMail(mailOptions, (error, info) => {
        if (error) {
            return console.log(error.message);
        }
        console.log('success ' + info);
    });

});

Answer 1

It seems that in this case, the only way to send the file is to read the entire stream and send it as a string or buffer:

const stream = examplePass.generate();

res.set({
    'Content-Type': 'application/vnd.apple.pkpass',
    'Content-disposition': `attachment; filename=${passName}.pkpass`,
});

stream.pipe(res);

const chunks = [];

stream.on('data', chunk => {
    chunks.push(chunk);
});

stream.on('end', () => {
    const content = Buffer.concat(chunks);

    const transporter = nodemailer.createTransport({
        host: 'smtp.gmail.com',
        port: 587,
        secure: false,
        requireTLS: true,
        auth: {
            user: '[email protected]',
            pass: 'password',
        },
    });

    const mailOptions = {
        from: '[email protected]',
        to: '[email protected]',
        subject: 'You\'re on your way to ',
        html: '<h1>Reciept email</h1>',
        attachments: [
            {
                filename: 'Event.pkpass',
                contentType: 'application/vnd.apple.pkpass',
                content
            },
        ],
    };

    transporter.sendMail(mailOptions, (error, info) => {
        if (error) {
            return console.log(error.message);
        }
        console.log('success:', info);
    });

});

BUT! You need to be careful with this approach if the file is large, as it is fully loaded into RAM.

Answer 2

Your problem is that you piped the stream to res which is a "StreamReader" aka consumer, instead you need just to pass it to nodeMailer which it is a StreamReader by itself.

const stream = examplePass.generate();

// res.set({
//   'Content-Type': 'application/vnd.apple.pkpass',
//   'Content-disposition': `attachment; filename=${passName}.pkpass`,
// });

// stream.pipe(res); <- remove this

//Send the receipt email

stream.on('finish', (attach) => {
  let transporter = nodemailer.createTransport({
    host: 'smtp.gmail.com',
    port: 587,
    secure: false,
    requireTLS: true,
    auth: {
      user: '[email protected]',
      pass: 'password',
    },
  });

  let mailOptions = {
    from: '[email protected]',
    to: '[email protected]',
    subject: "You're on your way to ",
    html: '<h1>Reciept email</h1>',
    attachments: [
      {
        filename: 'Event.pkpass',
        contentType: 'application/vnd.apple.pkpass',
        content: stream,
      },
    ],
  };

  transporter.sendMail(mailOptions, (error, info) => {
    if (error) {
      return console.log(error.message);
    }
    console.log('success ' + info);
  });
});

This is how I'm streaming email attachments.