Correct way to stream a `request` request?

Question

I am trying to create a ReadableStream object from a request, which eventually I want to pass it into the attachment variable for mailgun-js's data object:

var fileStream = null;
request(String(url)).pipe(fileStream);

msg.attachment = new mailgun.Attachment({
    data: fileStream,
    filename: 'my_custom_name.png',
    knownLength: fileStat.size,
    contentType: 'image/png'});

What's the correct way to do this?

Answer 1

Not tested, but worth giving a try:

var stream = new require('stream').PassThrough();

request(String(url)).pipe(stream);

msg.attachment = new mailgun.Attachment({
  data        : stream,
  filename    : 'my_custom_name.png',
  knownLength : fileStat.size,
  contentType : 'image/png'
});

request() doesn't seem to inherit from Stream, so directly passing it as data property won't work. Instead, a PassThrough stream is created, which inherits from both Readable and Writable.

The Readable part will be used by the Mailgun class, and the Writable part will get the HTTP response data piped into it.

Answer 2

I know this is a little late, but hopefully still helpful. Just submitted a pull request to have this functionality:

var request = require('request');
var file = request("https://www.google.ca/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png");

var data = {
  from: 'Excited User <[email protected]>',
  to: '[email protected]',
  subject: 'Hello',
  text: 'Testing some Mailgun awesomness!',
  attachment: file
};

mailgun.messages().send(data, function (error, body) {
  console.log(body);
});

If it doesn't get merged, you can see it here: https://github.com/antoniosou/mailgun-js