smtp-server.js

'use strict';

/* eslint-disable no-console */

// npm i smtp-server
// npm i mailparser

// https://nodemailer.com/extras/smtp-server/
// https://nodemailer.com/extras/mailparser/

// This is a very very simple SMTP server which you can use e.g. with nodemailer
// to test sending out email in a microservice. Just replace the transport, using
// something like this:

/*
const fakeTransport = {
  host: 'localhost', // or wherever this is running
  port: 2525,
  secure: false,
  ignoreTLS: true,
  auth: {
    user: 'doesnot',
    pass: 'matter'
  }
};
*/

// Create the server with `await createServer()`, get a list of received mails
// via `getReceivedEmails()` and reset them via `clearEmails()`.

const SmtpServer = require('smtp-server').SMTPServer;
const { simpleParser } = require('mailparser');

let _emails = [];

function createServer() {
  return new Promise((resolve, reject) => {
    const server = new SmtpServer({
      allowInsecureAuth: true,
      onAuth(auth, session, callback) {
        // Yeah, who needs auth
        return callback(null, { user: 'auto-user', data: 'not-used' });
      },
      onData(stream, session, callback) {
        stream.on('end', callback);
        (async () => {
          try {
            const content = await simpleParser(stream);
            _emails.push(content);
          } catch (err) {
            console.error('PARSING EMAIL FAILED HORRIBLY!');
            console.error(err);
            return callback(err);
          }
        })();
      }
    });
    // Replace the port if you feel like it.
    server.listen(2525, (err) => {
      err ? reject(err) : resolve();
    });
  });
}

function getReceivedEmails() {
  return _emails;
}

function clearEmails() {
  _emails = [];
}

module.exports = {
  createServer,
  getReceivedEmails,
  clearEmails
};