SMTP Server

Usage

import { SMTPServer } from '@typemail/smtp/server';

const server = new SMTPServer();

server.on('connection', conn => {
  conn.on('message', message => console.log(message));
});

message will be of the type SMTPMessage:

export interface SMTPMessage {
  recipients: string[];
  sender: string;
  message: string;
}

The message is a raw message that needs to be parsed. letterparser can be used to parse and extract data from the raw messages.

Options

The constructor for SMTPServer accepts an options object.

Property	Default value	Description
ip	0.0.0.0	IP address to bind to.
port	25	Port to bind to. (Ports under 1024 usually require superuser privileges.)
hostname	localhost	Hostname advertised by the SMTP server.
size	1000000	Maximum message size (in bytes).
tls	undefined	createSecureContext options for STARTTLS support.
tlsPort	465	Port for secure only communication, only enabled if tls is configured properly.
authenticate	undefined	Authentication function. See Authentication for more details.
authMethods	undefined	Array of authentication method strings. See Authentication for more details.

Events

listening

Emitted when all configured servers are listening.

message

Emitted when a message is succesfully received.

error

Emitted when an error occurs.

rejected

Emitted when a message is rejected. For now, this only happens when the message exceeds the maximum size.

Authentication

To enable authentication, a function of following type must be passed with the options object:

  authenticate?: (
    connection: SMTPServerConnection,
    method: string,
    payload?: { username: string; password: string; identity?: string; } | string[]
  ) => boolean | Promise<boolean>;

Custom methods can be supported in the following way:

import { SMTPServer } from '@typemail/smtp/server';

const server = new SMTPServer({
  supportedAuthenticationMethods: ['XOAUTH2', 'NTLM'],
  authenticate: async (connection, method, payload) => {
    switch (method) {
      case 'XOAUTH2':
        if (Array.isArray(payload) && typeof payload[0] === 'string') {
          // Validate payload and return the result.
          return true;
        }
        break;
      case 'NTLM':
        const negotiateResponse = await connection.challenge(
          'ntlm supported',
          true
        );
        // Test response.
        const authenticateResponse = await connection.challenge('anything');
        // Test response.
        return true;
        break;
    }

    return false;
  },
});

server.on('connection', conn => {
  conn.on('message', message => console.log(message));
});