smtpd-lite

node-smtpd-lite

An uncomplicated SMTP mail receiver for Node.js.

Quick example

var Server = require('smtpd-lite');

var server = new Server({
  host: 'mail.example.com',
  domain: 'example.com'
});

server.on('receive', function(mail) {
  console.log(mail);
});

server.listen(25);

Installation

# Install with npm
$ npm install smtpd-lite

# Install from source code
$ git clone https://github.com/g6123/node-smtpd-lite.git smtpd-lite

Dependency

• smtpd-lite uses new stream API (stream2), and is supported for Node.js v0.10+.
• Also node-icu-charset-detector can be optionally used for auto charset detection, which has dependency on libicu. Install guide is here.

Usage

Class: Server

This class inherits net.Server. You can use all methods and events from net.Server such as server.listen(), server.close(), server.on('error', function(error) { ... }), etc.

new Server(options)

options defines all settings for server and supoorts following properties :

• host : Hostname displayed on greeting message and respond to HELO/EHLO command. Server can be runned on different hostname. (default : '127.0.0.1')
• domain : Domain name displayed on greeting message (default : 'localhost')
• tls: When set this false, all TLS features are disabled. (default : false)
  • force : Whether to force client to use TLS
  • key : A string or buffer containing the private key of the server in PEM format. (Could be an array of keys). (Required if you use TLS)
  • cert : A string or buffer containing the certificate key of the server in PEM format. (Could be an array of certs). (Required if you use TLS)
  • ca: An array of strings or buffers of trusted certificates in PEM format. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.
  • ..and more TLS security context options. For more details, see here.
• auth : When set this false, all authentication features are disabled. (default : false)
  • force : Whether to force client to log in
  • type : An array of strings indicating types of authentication mechanism to be used. Only authentications with these mechanisms will be allowed.
• defaultCharset : Charset to use as default for parsing mails (default : 'UTF-8')
• tempDir : Path to temporary directory where body and mulitpart data files are stored (default : './tmp/')
• logFile : Path to log file. When set false, log file won't be created. (default : false)
• logLevel : Log level for logging - both for stdout and file (default : 'info')
  • debug : Display all logs including all messages from/to client.
  • info
  • warn
  • error

server.removeTemp([all])

Removes temporary files in the directory configured by config['tempDir']. If all argument is given true, it removes all files in the directory. Otherwise, it removes only empty (zero-size) files.

Event: 'sessionStart'

• Receiver receiver

Alias for sessionStart event of Receiver.

Event: 'sessionEnd'

• Parser parser

Alias for sessionEnd event of Receiver.

Event: 'parseStart'

• Parser parser

Alias for parseStart event of Parser.

Event: 'parseEnd'

• Object mail

Alias for parseEnd event of Parser.

Event: 'receive'

• Object mail

Another alias for parseEnd event of Parser.

---

Class: Receiver

receiver.replaceSocket(socket)

Replaces the socket which the receiver uses. Also it removes, from the old socket, event listeners registered by receiver, and sets the same listeners on the new socket.

receiver.socket

The socket a receiver is currently using.

receiver.isHello

Indicates whether or not HELO/EHLO message response was sent.

receiver.tlsStatus

There are four possible states.

• -1 means that TLS features are disabled.
• 0 means TLS features are enabled, but the socket is not secure due to failed negotiation or just because TLS negotiation has not yet started.
• 1 means the socket is secured with TLS.
• 2 means that server is negotiating with the client.

receiver.authStatus

There are four possible states.

• -1 means authentication is disabled.
• 0 means authentication feature is enabled, but the client has not yet logged in or the authentication has failed.
• 1 means the client has been authenticated successfully.
• 2 means authentication is in the progress.

receiver.from

receiver.to

Event: 'sessionStart'

Emitted when the server was connected to a new client or the client made a new session (RSET or the end of DATA.)

Event: 'auth'

• String data
• Function function callback(error) { ... }

Emitted when the client sends AUTH command. Until callback is called, all data chunks from the client is processed only by event listener listening on this auth event. When callback is called with error, the receiver will consider the authentication has failed. Below is an example code.

var Server = require('smtpd-lite');

var server = new Server({
	auth: {
		force: false,
		type: ['DIGEST-MD5', 'CRAM-MD5']
	}
});

server.on('sessionStart', function(receiver) {

	receiver.on('auth', function(data, callback) {

		// Authenticate the client with the given `data`..

		if(error) {

			receiver.socket.send(error + 'Authentication failed');

		} else {

			receiver.socket.send('235 Authentication successful');

		}

		callback(error);

	});

});

Event: 'sessionEnd'

• Parser parser

Emitted when the server reached the end of a mail or the client made new session (RSET or the end of DATA.) Not emitted when the connection has been closed or session been reset before any mail had been received.

---

Class: Parser

This class inherits stream.Transform. You can use all methods and events from stream.Transform such as parser.pipe(), parser.end(), parser.on('error', function(error) { ... }), etc.

Event: 'parseStart'

Emitted when the first line to be parsed is received.

Event: 'parseEnd'

• Object mail

mail argument is an object with following properties :

{
  id: String,
  header: { ... },
  body: {
    stream: stream.Readable stream,
    length: Number
  },
  multiparts: [
    {
      header: { ... },
      stream: stream.Readable stream,
      length: Number
    }, ...
  ]
}

• id: An unique string of the session where the mail was received.
• header : An object containing headers of the received mail. All keys are converted to the lowercase.
• body : An object containing a body of the received mail.
  • stream : A readable stream of the temporary body file.
  • length: Total size of the data written on stream.
• multiparts : An array of mime multiparts of the received mail.
  • header : An object containing headers of each multipart. All keys are converted to the lowercase.
  • stream : A readable stream of each temporary multipart file.
  • length: Total size of the data written on each stream.