node-smpp

SMPP client and server implementation in node.js.

Introduction

This is a complete implementation of SMPP v5.0 in node.js, with support for custom commands and TLVs.

SMPP v5.0, by design, is backward compatible with v3.4, so you would be able to use this module with 3.4 implementations. Even you can use this module with 3.3 implementations as far as you don't use TLV parameters and don't bind in transceiver mode.

The name of the methods and parameters in this implementation are equivalent to the names defined in SMPP specification. So get a copy of SMPP v5.0 Specification for a list of available operations and their parameters.

Installation

npm install smpp

Usage

Creating a SMPP session

var smpp = require('smpp');
var session = smpp.connect({
	url: 'smpp://example.com:2775',
	auto_enquire_link_period: 10000,
	debug: true
}, function() {
	session.bind_transceiver({
		system_id: 'YOUR_SYSTEM_ID',
		password: 'YOUR_PASSWORD'
	}, function(pdu) {
		if (pdu.command_status === 0) {
			// Successfully bound
			session.submit_sm({
				destination_addr: 'DESTINATION NUMBER',
				short_message: 'Hello!'
			}, function(pdu) {
				if (pdu.command_status === 0) {
					// Message successfully sent
					console.log(pdu.message_id);
				}
			});
		}
	});
});

Creating a SMPP server

var smpp = require('smpp');
var server = smpp.createServer({
	debug: true
}, function(session) {
	session.on('error', function (err) {
		// Something ocurred, not listening for this event will terminate the program
  	});
	session.on('bind_transceiver', function(pdu) {
		// we pause the session to prevent further incoming pdu events,
		// untill we authorize the session with some async operation.
		session.pause();
		checkAsyncUserPass(pdu.system_id, pdu.password, function(err) {
			if (err) {
				session.send(pdu.response({
					command_status: smpp.ESME_RBINDFAIL
				}));
				session.close();
				return;
			}
			session.send(pdu.response());
			session.resume();
		});
	});
});

server.listen(2775);

It's very important to listen for session errors, not listening for error events will terminate the program.

Debug

To enable a simple debug of ingoing/outgoing messages pass debug: true as server/client option. Debug is disabled by default.

Alternatively, you can listen for the debug event and write your own implementation:

session.on('debug', function(type, msg, payload) {
	console.log({type: type, msg: msg, payload: payload});
});

A debugListener option is also supported:

var options = {
	debug: false,
	debugListener: function(type, msg, payload) {
		console.log({type: type, msg: msg, payload: payload});
	}
}

Handling client connection errors

In case of errors while trying to connect, an error event will be emitted by the session and the program will be terminated if it's not listened. This is how you should check for errors.

session.on('error', function(e) {
	// empty callback to catch emitted errors to prevent exit due unhandled errors
	if (e.code === "ETIMEOUT") {
		// TIMEOUT
	} else if (e.code === "ECONNREFUSED" {
		// CONNECTION REFUSED
	} else {
		// OTHER ERROR
	}
});

Connection timeout

By default the socket will be dropped after 30000 ms if it doesn't connect. A connectTimeout option can be sent when making connections with the server in order to change this setting.

Proxy protocol

Proxy Protocol v1 is now supported as an experimental feature, both for TCP4 and TCP6.

Pass enable_proxy_protocol_detection: true as server option to enable proxy protocol detection, if the option is not provided the feature is completely ignored.

• session.remoteAddress will contain the proxied source IP.
• session.proxyProtocolProxy will contain the proxy IP.
• Even with proxy protocol detection enabled the server will understand non-proxied requests.
• Security: Proxy CIDRs validation is yet to be implemented.
• Uses findhit-proxywrap, a third party library to wrap the net/tls implementations and decode the proxy-protocol
• header before forwarding it to the standard implementations.

Compatibility issues

• On proxied, non-tls connections (with Nodejs < v8): Proxywrap shows some misbehaviour with the way this library inherits from the net server, the socket looses the ability to emit events. As a minor-fix, the socket.emit method is backed up and restored after the proxying to the net server, making everything work as expected.

Encodings

This smpp implementation supports 3 encodings: ASCII (GSM 03.38), LATIN1, and UCS2. data_coding for these encodings are 0x01, 0x03, and 0x08 respectively.

Default encoding for data_coding:0 is ASCII. You can change it as follows:

smpp.encodings.default = 'LATIN1';

String messages will be automatically encoded using one of these three encodings. If the SMSC you are communicating with doesn't support one of these encodings, you can simply remove it as follows:

delete smpp.encodings.ASCII;

You can also manually convert a message to a buffer and pass it as short_message or message_payload parameter to bypass automatic message encoding.

API

smpp.connect(url, [callback])

Creates a new smpp session using the specified connection url. url must be a string in this format: smpp://host:port. To establish a secure smpp connection use ssmpp as scheme like in ssmpp://host:port. If port is omitted in the url, the default port (2775 for smpp and 3550 for secure smpp) will be used. If called without arguments, smpp://localhost:2775 will be assumed.

The callback, if specified, will be added as a listener for the connect event in plain connections and secureConnect event in secure connections.

smpp.Session

This is the base object for a SMPP session. sessions can be created by calling smpp.connect() or can be created by a smpp server when a client establishes a connection to the server. In this case the server passes the session object to the 'session' event listener.

session.send(pdu, [responseCallback], [sendCallback], [failureCallback])

Sends a pdu request/response to the MC/ESME over the session. The pdu is an instance of smpp.PDU which might be either a response or a request pdu.

When sending a request pdu, pdu.sequence_number will be automatically set to the proper value.

If the pdu is a request pdu, when the relevant response is received, the optional responseCallback parameter will be invoked with the response pdu passed to it.

Optional sendCallback will be called when the pdu is successfully flushed.

Optional failureCallback will be called whenever it is not possible to write to the socket.

session.close([callback])

Closes the current session connection. If supplied, the callback is called once the session is fully closed.

session.destroy([callback])

Forcibly closes the current session connection. This aids some broken servers, that don't honor gracefull tear-down. ( Looking at you SMPPSim ) If supplied, the callback is called once the session is fully closed.

session.connect()

Can be used to reconnect a closed connection.

session.pause()

Can be used to postpone incoming pdu events untill calling session.resume().

session.resume()

Resumes the session after a call to pause().

Shortcut methods

For all smpp operations you can call methods with the same name as the operation name, which is equivalent to createing a pdu instance and then sending it over the session.

For example calling session.submit_sm(options, [responseCallback], [sendCallback], [failureCallback]) is equivalent to:

var pdu = new smpp.PDU('submit_sm', options);
session.send(pdu, responseCallback);

Event: 'connect'

Emitted when the session connection successfully is established.

Event: 'secureConnect'

The secureConnect event is emitted after the handshaking process for a secure connection has successfully completed.

Event: 'close'

Emitted when the connection is fully closed.

Event: 'error' (error)

Emitted when an error occurs. The 'close' event will be called directly following this event.

Event: 'send' (pdu)

Emitted when a pdu is being sent over the session with the pdu as the argument.

Event: 'pdu' (pdu)

Emitted upon receiving a pdu.

Event: 'unknown' (pdu)

Emitted upon receiving an unknown pdu.

Shortcut events

When a pdu is received, after emitting the 'pdu' event, an event with the same name as the operation of that pdu will also be emitted.

smpp.createServer([options], [sessionListener])

Creates a new SMPP server. The sessionListener argument is automatically set as a listener for the 'session' event. If options include key and cert, a TLS secured server will be created. Include rejectUnauthorized: false to disable the certificate validation.

smpp.Server

The base object for a SMPP server created with smpp.createServer(). It is a child class of node's net.Server.

server.listen([port], [host], [callback])

Begin accepting connections on the specified port and host. If port is omitted 2775 will be used. If the host is omitted, the server will accept connections directed to any IPv4 address.

This function is asynchronous. The last parameter callback will be called when the server has been bound.

Event: 'session' (session)

Emitted when a new session connection is established. session is an instance of smpp.Session.

for other server methods/events documentations see node's net.Server docs.

smpp.PDU

This is the base object for a PDU request or response.

new smpp.PDU(command, [options])

Creates a new PDU object with the specified command and options.

options is a list of parameters acceptable by the specified command. The name of the parameters are equivalent to the names specified in SMPP specification v5.0. The order of the parameters doesn't matter. If you don't specify a required parameter in options a default value (usually null or 0 for integers) will be used.

For the type of the parameters note the following rules:

• For Integer parameters (no matter what the length is) you must specify a value of type number in JavaScript.
• For Octet-String and COctet-String parameters you can specify either a Buffer or a String.
• For the fields that accept SMPP Time Format (broadcast_end_time, schedule_delivery_time, validity_period, final_date) you can specify a Javascript Date instance which will be automatically converted to a SMPP absolute time string. For relative times you don't need to specify the whole string, specifying a portion of it is enough. for example '0430' will be converted to '000000000430000R'.
• For short_message and message_payload fields you can specify a buffer or a string or an object containing udh and message properties, while udh is a buffer and message is either a string or a buffer. strings will be automatically encoded using ASCII, LATIN1, or UCS2 depending on their characters. data_coding (if not specified) will be automatically set to 0x01, 0x03, or 0x08 for ASCII, LATIN1, and UCS2 encodings respectively. Also UDH indicator bit in esm_class is automatically set if udh exists.
• sm_length parameter is not needed. It will be automatically set depending on the length of the short_message.
• dest_address parameter in submit_multi operation must be an array of objects containing either dest_addr_ton, dest_addr_npi and, destination_addr properties or dl_name property for SME addresses or Distribution Lists respectively.
• unsuccess_sme parameter in submit_multi_resp operation must be an array of objects containing dest_addr_ton, dest_addr_npi, destination_addr and, error_status_code properties.
• number_of_dests and no_unsuccess parameters are not needed. They will be automatically set depending on the dest_address and unsuccess_sme parameters respectively.
• TLV parameters which can be specified multiple times (e.g. broadcast_area_identifier), must be specified as an array, even if you want to specifiy just one item.

pdu.isResponse()

Returns true if the pdu is a response pdu, otherwise returns false;

pdu.response([options])

For a request pdu, calling response() creates and returns a response pdu for that request.

For an unknown pdu, response() creates and returns a generic_nack pdu.

session.on('submit_sm', function(pdu) {
	var msgid = .... ; // generate a message_id for this message.
	session.send(pdu.response({
		message_id: msgid
	}));
});

session.on('unbind', function(pdu) {
	session.send(pdu.response());
	session.close();
});

session.on('enquire_link', function(pdu) {
	session.send(pdu.response());
});

Upgrade notes

upgrade to version 0.6.0

• Support for Nodejs < v4 (2015) has been dropped due compatibility issues with findhit-proxywrap library
• Proxy protocol v1 support has been added as an experimental feature. Disabled by default, will be completely ignored if not enabled.

Roadmap

• Add some usage examples (e.g client, server, and cluster examples)

License

node-smpp is released under the MIT license.