Stream transport

Stream Transport is not actually a transport, it’s more like a testing add-on as instead of delivering the message it processes input data and returns you the generated RFC822 email message either as a stream or a Buffer. Additionally you can define which kind of newlines to use, either the ‘windows’ style (<CR><LF>) or the ‘unix’ style (<LF>). This transport is mostly useful for testing and also for scenarios where you want to use Nodemailer plugins to process the message and do the actual delivery by some other means.

To use Stream Transport, set streamTransport in Nodemailer transport options to true in Nodemailer options. If you want the transport to return buffers instead of streams, set buffer option to true. For newline selection use newline property (defaults to ‘unix’)

The info argument for sendMail() callback includes the following properties:

  • envelope – is an envelope object {from:‘address’, to:[‘address’]}
  • messageId – is the Message-ID header value
  • message – is either stream (default) of buffer depending on the options

JSON transport

Another alternative instead of streaming is JSON transport (available since Nodemailer v3.1.0). In this case the message object would include a JSON string that in turn could be used as input for Nodemailer. All attachments, web content etc. are converted into base64 encoded strings. Address strings are parsed into address objects. The only downside is that raw property is not supported.

Examples

1. Stream a message with windows-style newlines

let transporter = nodemailer.createTransport({
    streamTransport: true,
    newline: 'windows'
});
transporter.sendMail({
    from: [email protected]',
    to: [email protected]',
    subject: 'Message',
    text: 'I hope this message gets streamed!'
}, (err, info) => {
    console.log(info.envelope);
    console.log(info.messageId);
    info.message.pipe(process.stdout);
});

2. Create a buffer with unix-style newlines

let transporter = nodemailer.createTransport({
    streamTransport: true,
    newline: 'unix',
    buffer: true
});
transporter.sendMail({
    from: [email protected]',
    to: [email protected]',
    subject: 'Message',
    text: 'I hope this message gets buffered!'
}, (err, info) => {
    console.log(info.envelope);
    console.log(info.messageId);
    console.log(info.message.toString());
});

3. Create a JSON encoded message object

let transporter = nodemailer.createTransport({
    jsonTransport: true
});
transporter.sendMail({
    from: [email protected]',
    to: [email protected]',
    subject: 'Message',
    text: 'I hope this message gets buffered!'
}, (err, info) => {
    console.log(info.envelope);
    console.log(info.messageId);
    console.log(info.message); // JSON string
});

The contents of info.message (string value) would look like this:

{
   "from":{
      "address":"[email protected]",
      "name":""
   },
   "to":[
      {
         "address":"[email protected]",
         "name":""
      }
   ],
   "subject":"Message",
   "text":"I hope this message gets buffered!",
   "headers":{

   },
   "messageId":"<[email protected]>"
}