Woo Downloads Sent via Email Attachement

add_filter( 'woocommerce_email_attachments', 'attach_downloadable_files_to_customer_completed_email', 10, 3 );
function attach_downloadable_files_to_customer_completed_email( $attachments, $email_id, $order ) {
    if( isset( $email_id ) && $email_id === 'customer_completed_order' ){
        // Loop through order items
        foreach( $order->get_items() as $item ) {
            $product = $item->get_product(); // The product Object

            if ( $product->is_downloadable() && ( $downloads = $product->get_downloads() ) ) {
                // Loop through product downloads
                foreach( $downloads as $download ) {
                    $attachments[] = $download->get_file();
                }
            }
        }
    }
    return $attachments;
}

var userId = (find some user sys_id);
var session = gs.getSession();
session.impersonate(userId);

app.get('/:id/tracker.png', function(request, response, next) {
    var emailId = request.param.id;
    var buf = new Buffer([
        0x47, 0x49, 0x46, 0x38, 0x39, 0x61, 0x01, 0x00, 0x01, 0x00,
        0x80, 0x00, 0x00, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x2c,
        0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x02,
        0x02, 0x44, 0x01, 0x00, 0x3b
    ]);
    response.set('Content-Type', 'image/png');
    response.end(buf, 'binary');
    db.findOne({ id: emailId }, function(error, email) {
        if(error) return next(error);
        app.emit('event:opened', email);
    });
});

app.on('event:opened', function(email) {
    console.log('Email was opened');
    console.log(email.to);
    console.log(email.subject);
});