@larvit/smpp

SMPP 3.4 client and server for Node.js with the session layer built in: keepalive, reconnect, send window, long messages and delivery receipts. TypeScript, ESM, no dependencies.

• Keepalive. enquire_link every 20 s on a quiet link; a peer that stops answering is dropped.
• Reconnect. A dropped client link re-binds on its own, backing off from 1 s to 30 s.
• Send window. 10 requests in flight; further sends queue instead of overrunning the SMSC.
• Long messages. Split on send, reassembled on receive, in both the UDH and sar_* spellings.
• Delivery receipts. Read from TLVs or from receipt text, matched to the ids you were given.
• Graceful shutdown. close() waits for what is in flight, so neither end has to guess.
• Never throws. Every fallible call resolves to { err?, … }.
• Interoperable. Tested as a client against Jasmin and SMPPSim, and as a server against Kannel, jsmpp, Cloudhopper, python-smpplib and php-smpp: interop-tests/.

Install · Send an SMS · Delivery reports · Receive SMS · Run an SMPP server · Errors · Client options · Server options · Send options · Session · Receiving in depth · Server in depth · Logging · PDUs and the low-level API · Migrating from 0.4.0 · Development

Install

npm install @larvit/smpp

Node 18 or later. ESM only, types included.

Send an SMS

import { client } from '@larvit/smpp';

const { err, session } = await client();
if (err) throw err;

await session.sendSms({
	from:    '46701113311',
	message: 'Hello world',
	to:      '46709771337',
});

await session.unbind();

Without options this binds to localhost:2775 as a transceiver with the default credentials. A real SMSC needs host, port, username and password: Client options. A message longer than one SMS is split and sent as one concatenated message: Send options.

Delivery reports

Connection parameters, a receipt per segment, and logging:

import { Log } from '@larvit/log';
import { client } from '@larvit/smpp';

const log = new Log('debug');

const { err, session } = await client({
	host:     'smpp.somewhere.com',
	log,
	password: 'bar',
	port:     2775,
	username: 'foo',
});
if (err) throw err;

session.on('dlr', dlr => {
	// dlr.smsId, dlr.statusMsg, dlr.statusId
});

const { err: sendErr, smsIds } = await session.sendSms({
	dlr:     true,
	from:    '46701113311',
	message: '«baff»',
	to:      '46709771337',
});

dlr: true asks the SMSC to report on each segment. Match dlr.smsId against the smsIds the send returned. statusMsg is DELIVERED, UNDELIVERABLE, EXPIRED and so on; intermediate is true for a report that is not final. The full shape, the messageDlr event that merges a long message's receipts into one, and SMSCs that write ids in two notations: Delivery receipts.

Receive SMS

A receiver or transceiver client gets mobile-originated messages as sms events:

session.on('sms', async sms => {
	// sms.from, sms.to, sms.message
	await sms.sendResp();
});

Call sendResp() for every message; it is part of the protocol. Delivery receipts reach you as dlr events, not here. A multipart message arrives reassembled and already answered segment by segment, so sendResp() there only says you are done with it: Receiving in depth.

Run an SMPP server

import { server } from '@larvit/smpp';

const { err, server: smpp } = await server();
if (err) throw err;

smpp.on('session', session => {
	session.on('sms', async sms => {
		// sms.from, sms.to, sms.message, sms.dlr
		await sms.sendResp();
	});
});

With authentication and delivery reports:

import { server } from '@larvit/smpp';

const { err, server: smpp } = await server({
	// Replace with your own auth. Returning an object attaches it to session.userData.
	authenticate: async ({ password, systemId }) => {
		if (systemId !== 'foo' || password !== 'bar') return false;

		return { userData: { userId: 123 } };
	},
});
if (err) throw err;

smpp.on('session', session => {
	session.on('sms', async sms => {
		if (sms.answeredOnArrival) {
			await sms.sendResp(); // multipart: already answered per segment; this only releases the shutdown drain
		} else {
			// no args: ESME_ROK + generated id; or sendResp({ smsId, status: 'ESME_RMSGQFUL' })
			await sms.sendResp();
		}

		if (sms.dlr) {
			await sms.sendDlr(); // same as sms.sendDlr('DELIVERED')
		}
	});
});

console.log(smpp.port);  // the port actually bound, useful when 0 was requested
await smpp.close();      // stop listening, then drain and close every live session

• sendResp() answers ESME_ROK with a generated UUID v7 as the message id. sendResp({ smsId, status }) names the id or refuses the message.
• sms.dlr is true where the sender asked for a receipt. sendDlr() reports DELIVERED, sendDlr('UNDELIVERABLE') any other state: Server in depth.
• A message that arrived in several segments was answered as they arrived, so sendResp() there takes no smsId or refusing status. sms.answeredOnArrival says which case you are in.
• smpp.close() stops listening, then drains and closes every live session.

Errors

Nothing throws. Every fallible call returns a result with an optional err:

const { err, session } = await client({ host: 'smpp.somewhere.com' });
if (err) return;

const { err: sendErr, smsIds } = await session.sendSms({ from, message, to });

Failures on a live session arrive as sessionError events, on a server handle as serverError. Neither is named error, because Node throws on an unhandled error event.

sessionError carries three kinds of failure:

Kind	Type
A PDU the peer sent that the codec could not read. The link stays up; only that PDU is lost.	PduRefusedError	Count it.
A concatenated message given up on before it was whole. Its segments were answered, so the peer will not resend, and no sms fired for it.	Error	Count it as lost traffic.
The session or socket failing, or a hook or listener that threw or rejected.	Error	Alert.

The last two are told apart by message text only, so this alerts on both:

import { PduRefusedError } from '@larvit/smpp';

session.on('sessionError', err => {
	if (err instanceof PduRefusedError) {
		log.warn('the peer sent a PDU that could not be read', {
			cmdName: err.header.cmdName ?? err.header.cmdId,
			reason: err.reason,
		});

		return;
	}

	log.error('a session failure or lost traffic', { message: err.message });
});

• reason is command, body or tlvs: the part the codec stopped at.
• header is the 16 octets that did parse: cmdId, cmdLength, cmdName, cmdStatusId and seqNr. cmdName is undefined for a command id this library does not know. PduHeader is its type.
• A refused request is answered with the status SMPP names for it. A refused response is answered with nothing, and settles the request it named as unanswered.
• A refused inbound deliver_sm is lost traffic: a message or receipt that never arrives as sms or dlr. A refused response is reported twice, as the err of the sendSms() or send() waiting on it and here.
• A PduRefusedError is always a PDU that arrived. What this library refuses to build or send (an alphabet, a time, a body its data_coding cannot carry) is a plain Error in the call's result.

Client options

All optional. Timeouts and delays are milliseconds.

Option	Default
host, port	localhost, 2775	Where to connect.
username, password	user, pass	Bind credentials: system_id and password.
bindType	transceiver	transceiver, transmitter or receiver.
interfaceVersion	0x34	The SMPP version declared at bind. 0x50 for an SMSC that requires SMPP 5.0.
systemType, addressRange, addrTon, addrNpi	'', '', 0, 0	The remaining bind fields, for operators that require them.
tls	false	true for defaults, or a tls.ConnectionOptions object for a private CA or a client certificate.
enquireLinkInterval	20000	Interval between enquire_link on a quiet link.
idleTimeout	2 × enquireLinkInterval	Give up on a link the peer has stopped answering, and re-bind unless reconnect is false.
responseTimeout	30000	How long to wait for a response, and how long a send with no link waits for the next one. 0 waits forever.
shutdownTimeout	5000	How long close() and unbind() wait for requests already sent and messages not yet answered. 0 waits forever for the requests, which end when the peer answers or responseTimeout expires, so both at 0 never ends. The messages then fall back to responseTimeout, or to its default where that is 0 too.
maxOutstanding	10	Requests on the wire at once; further sends queue.
smsIdFormat	—	The notation the SMSC writes message ids in, per place: { receipt: 'decimal', submitResp: 'hex' }. Only where the two disagree: Delivery receipts.
reconnect	on	{ minDelay, maxDelay } retunes the backoff; false turns it off, so a drop ends the session; { fromStart: true } retries the first connect too.
log	silent	Any object with debug, error, info, verbose and warn methods: Logging.
signal	—	An AbortSignal that cancels connecting and tears the session down.

Reconnect. After a drop, an idle timeout, or a stream the library cannot frame, the client reopens the socket and re-binds, doubling the delay from minDelay (1 s) to maxDelay (30 s), and starts over at minDelay once a link has lasted maxDelay.

reconnect: { fromStart: true } puts the first connect and bind through the same loop, a bind the SMSC refuses included, so a client started while its SMSC is down keeps retrying. client() then resolves once bound, and only an aborted signal ends the wait. That signal also closes the session once bound, so write a deadline as an AbortController you stop arming when client() returns, not as AbortSignal.timeout(ms).

Server options

All optional. Timeouts are milliseconds.

Option	Default
host, port	all interfaces, 2775	Where to listen. port: 0 takes any free port; smpp.port says which.
authenticate	accept everything	({ password, session, systemId, systemType }) => false | { userData }, sync or async.
onRequest	none	(session, pduObj) => true | false, sync or async. First refusal on every request a bound peer sends: Server in depth.
systemId	''	The SMSC identity returned in the bind response.
interfaceVersion	0x34	The SMPP version advertised in the bind response. Optional parameters are sent to a peer from 0x34 up, whatever this is set to.
tls	false	A tls.TlsOptions object with your certificate and key. A bare true is refused.
idleTimeout	40000	Drop a peer that has been silent this long.
maxReassembly	1000	Incomplete multipart messages held per session.
maxOctets	67108864	Bytes of incomplete multipart messages held per session.
reassemblyTimeout	300000	How long a late segment can still join an incomplete message.
responseTimeout, shutdownTimeout, maxOutstanding, log, signal	as for the client

Send options

await session.sendSms({
	dlr:                  true,        // ask for a delivery report
	destinationAddrNpi:   0,           // override the numbering plan of the recipient
	destinationAddrTon:   1,
	encoding:             'UCS2',      // override the automatic choice
	flash:                false,
	from:                 'MyBrand',   // alphanumeric -> TON 5, digits -> TON 1
	maxSegments:          10,          // refuse a longer message instead of sending it
	message:              'Hello world',
	messagingMode:        'SMSC_DEFAULT', // or DATAGRAM or STORE_FORWARD
	scheduleDeliveryTime: new Date(Date.now() + 3600_000),
	sourceAddrNpi:        0,           // override the numbering plan of the sender
	sourceAddrTon:        5,
	to:                   '46709771337',
	validityPeriod:       3600,        // seconds, or a Date
}, { signal });                       // optional per-call AbortSignal

Addresses. sourceAddrTon and destinationAddrTon default to 5 for an alphanumeric address and 1 for a numeric one; the NPI fields default to 0.

Encoding.

encoding	Alphabet	Characters per SMS	Per segment of a long message
ASCII	GSM 03.38 7-bit	160	153
LATIN1	ISO 8859-1	140	134
UCS2	UCS-2	70	67

• Omitted: ASCII where the message fits GSM 7-bit, otherwise UCS2. LATIN1 only when named. Any other name is refused.
• GSM extension characters ({}[]\~^|€ and form feed) count as two, as does a character outside the basic multilingual plane in UCS2.
• An alphabet you name has to carry every character, or the send is refused before anything goes out, naming the character, its code point and its index. Detection never refuses.
• LATIN1 carries every octet, so buffer.toString('latin1') reaches the SMSC byte for byte, under data_coding 0x03, which declares Latin-1 text. To declare 8-bit binary, hand session.send() a Buffer body and the data_coding you want: PDUs and the low-level API.
• consts.ENCODING is the low-level data_coding table, not this option's list.

Long messages.

const { err, pduObjs, smsIds, unanswered } = await session.sendSms({ from, message, to });

• One id per segment. smsIds is positional with pduObjs, and an entry is undefined where the SMSC took the segment without naming an id; some name one for the first segment only. No receipt ever carries an empty id, so an unnamed entry matches nothing.
• err is set when the SMSC refuses a segment, naming the status. Every segment goes out together, so pduObjs and smsIds then hold what was accepted: enough to reconcile a later receipt, not enough to resend the rest. Treat a partial failure as a failed message.
• unanswered counts segments that went out and were never answered. The SMSC may have taken each and lost only the response, so a message with unanswered above zero cannot be resent without risking a duplicate.
• More than 255 segments is refused before anything is sent, since the concatenation header numbers segments in one octet. maxSegments lowers that ceiling; most handsets and SMSCs stop well short.

Flash. flash: true asks for GSM 03.38 message class 0, shown on arrival instead of stored. It travels in data_coding beside the alphabet, so a flash UCS2 message stays UCS2. flash with encoding: 'LATIN1' is refused: no data_coding carries both.

Messaging mode. messagingMode names the esm_class mode: SMSC_DEFAULT, which is what an omitted option sends, DATAGRAM or STORE_FORWARD. Every segment of a long message also carries the user data header indicator, so STORE_FORWARD on one sends esm_class 0x43. DATAGRAM with dlr: true is refused, since datagram mode has no delivery reports. Transaction mode (consts.MESSAGING_MODE.FORWARD) exists only on data_sm, which is never sent, and is refused too.

Times. scheduleDeliveryTime and validityPeriod take a Date, a number of seconds, or a stamp you formatted. Refused before anything goes out: an invalid Date, NaN, Infinity, a negative count, and a count past 99 days 23:59:59, since a count in seconds is spelled in days and below. Name a later instant as a Date, which goes out absolute.

What gets checked. The library checks what it composes: an alphabet or a time you named, a string body under a data_coding you named. What you formed yourself, a Buffer body or a stamp you formatted, passes through as written. The same rule holds for session.send().

Session

Events

Event	Fires when
sms	An SMS arrives, reassembled if it was multipart. Carries sendResp(), sendDlr() and smsId.
dlr	A delivery report arrives, one per segment, with its PDU as the second argument: Delivery receipts.
messageDlr	Every segment of a long message sent with dlr: true has a final report: Delivery receipts.
close	The session is over and nothing will bring the link back. Fires once, whether you closed it or the link failed for good.
disconnected	The link dropped and the reconnect loop will retry. Do not open a replacement client: this session comes back on its own, and reconnected says when. Fires again for each attempt that reconnects and then fails, so it is not one-to-one with reconnected.
reconnected	The client re-bound after a drop.
sessionError	Something failed on a live session, a PDU the codec refused included: Errors.
data	Raw bytes arrived on the socket.
incomingPdu	A complete PDU arrived, as a buffer.
incomingPduObj	The same PDU, parsed into an object.

Methods

sendSms(), send(), sendReturn(), unbind() and close().

Shutdown. close() and unbind() both:

1. Refuse further sends. sendDlr() is the one send let past, when issued straight after sendResp(); await anything in between and it races the shutdown like any other send.
2. Wait up to shutdownTimeout for the requests already sent, and for every sms the application has not answered. That wait ends when sendResp() puts the response on the wire (or, for a message answered on arrival, when it is called at all), or when every listener that took the message has failed. Answering through sendReturn() instead leaves the wait running.
3. Tear down what is left, resolving to an err that says what was lost.

At most 1000 unanswered messages are held, for five minutes each; what falls out of either bound is dropped with a warning on the log and waited for no longer. Neither bound is an option. close({ signal }) cuts the wait short. unbind() takes no signal, and waits a further responseTimeout for its own response.

Sends and the link.

• A send issued while the link is down waits for the reconnect and goes out once the new link is bound, up to responseTimeout, after which it gives up having sent nothing.
• A request already on the wire when the link drops, when the peer fails to answer in time, or when you abort it, fails and counts in unanswered: the SMSC may have taken it and lost only the response.
• With reconnect: false a drop ends the session, and every send after it is refused.
• sms.sendResp() on a message whose link dropped writes nothing and returns err, since a response carries the sequence number of the link it arrived on. sms.sendDlr() still goes out on the new link.
• responseTimeout bounds the wait for a link and the wait for an answer separately, and the wait for a maxOutstanding slot is unbounded, so it is not a deadline. For a deadline pass { signal: AbortSignal.timeout(ms) }: it cuts all three waits short, and a send it stops before anything reached the socket adds nothing to unanswered. A message with more segments than slots goes out a slot at a time, so a deadline that expires mid-message is how you get a partial failure.
• There is no throughput limit. An operator's rate limit is per account, across every process bound to it, so enforce it outside this library. ESME_RTHROTTLED reaches you as a send's err.

Raw commands. send() reaches all 33 SMPP commands, not just the four the session handles itself:

const { err, pduObj } = await session.send({
	cmdName: 'query_sm',
	params: { message_id: smsId },
});

The peer.

• acceptsOptionalParams(): whether the peer declared SMPP 3.4 or later, the version from which optional parameters may be sent to it. The library's own senders check it before attaching a TLV; a send() you build is passed through as written, so check it yourself.
• peerInterfaceVersion: the version the peer declared, 0x00 if none.
• bindAllows(cmdName) and boundAs: what the bind direction carries: Bind direction.

Receiving in depth

• Multipart. Segments tied together by a user data header, or by the sar_msg_ref_num, sar_total_segments and sar_segment_seqnum TLVs, reassemble into one sms alike. A PDU carrying both is read from the header. The two reference numbers are separate counters: the same number in each is two messages.
• Answered on arrival. Each segment was answered as it landed, before you see the message: Server in depth.
• Where the body is. A body in the message_payload TLV, SMPP's way of carrying up to 64 KB and the only place a data_sm has, reads exactly like one in short_message, concatenated messages and receipts included. A PDU filling both is read from short_message.
• data_sm. A client reads an inbound data_sm as a delivery: a message arrives as sms, a receipt as dlr. A server() session reads it as a submission and always emits sms. Either way it is answered data_sm_resp.
• Flash. sms.flash is true where data_coding carries GSM 03.38 message class 0, in every coding group that carries one: 0x10, 0x18, 0x50 and 0xF0 alike. Classes 1 to 3 name where the handset stores the message and are not flash.
• Binary. A message whose data_coding says 8-bit binary arrives as Latin-1: Buffer.from(sms.message, 'latin1') gives the original octets.

Delivery receipts

Receipts travel on the same command as messages but reach you as dlr, one per segment. What marks one: esm_class; where that names no type, a receipted_message_id TLV; failing both, id: and stat: in the body. The body is read as text whatever data_coding the receipt declares, since SMSCs commonly copy the reported message's onto it. An intermediate delivery notification is a report too, never an inbound message.

Dlr field
smsId	The id reported on. undefined where the receipt carries no readable id.
statusMsg	DELIVERED, UNDELIVERABLE, EXPIRED, REJECTED, DELETED, ACCEPTED, UNKNOWN, ENROUTE, SCHEDULED or SKIPPED. stat:FAILED, which several operators write and SMPP does not define, reads as UNDELIVERABLE.
statusId	The numeric message_state. Where the peer sent one this library cannot name, its raw value, with statusMsg from the body or UNKNOWN.
intermediate	The report is not final: marked an intermediate notification, or reporting ENROUTE or SCHEDULED.
receipt	The receipt text parsed: id, sub, dlvrd, submitDate, doneDate, stat as the SMSC wrote it, err and text.
doneDate, errorCode	The done date: field as a Date, and the err: field.

Matching a receipt to a send means comparing dlr.smsId with the smsIds from sendSms(). Some SMSCs write the two in different notations, a hex message_id on the submit_sm_resp and a decimal id: in the receipt, or one of them zero-padded, and the comparison then matches nothing. Name each notation and both are read into plain decimal:

const { err, session } = await client({ smsIdFormat: { receipt: 'decimal', submitResp: 'hex' } });

receipt is the notation of the body's id:; submitResp that of the message_id in submit_sm_resp and of the receipted_message_id TLV, which carries that same id. An id that is not a number in the notation named is left as it arrived. The PDUs carry what the peer wrote either way: pduObjs from the send, and the dlr event's second argument.

messageDlr fires once every segment of a long message sent with dlr: true has a final report, carrying the worst status of the segments and each of them under segments. An intermediate report never counts. Merging needs the SMSC to number its segment ids <base>-<n>, this library's own server's convention; an SMSC that hands out unrelated ids per segment never fires it. A base is merged once: a later message the SMSC gives the same ids is reported through dlr alone, and an earlier one still collecting loses its merged report.

Server in depth

Multipart is answered on arrival. Each segment is answered as it lands, because a relaying SMSC will not send the next until the last is answered. The answer is ESME_ROK, unless the segment numbers itself into no message this session can join, which refuses it, or the reassembly buffer is full, which asks the SMSC to keep it and try again. sms.answeredOnArrival says whether the message you hold was answered that way; a segment count cannot, since a peer may number a message one part of one.

• The id was fixed with the first segment, so sendResp() there only says you are done, and returns err for an smsId or a refusing status.
• sms.smsId is the base. sendDlr() names <smsId>-1, <smsId>-2 and so on: the ids the submit_sm responses carried.
• A deliver_sm is answered with no id at all, since SMPP marks that field unused, so an inbound message's base is a handle of your own only.

Refusing a request for a reason in the request rather than the message (a full queue, an unknown recipient, an unauthorised sender) has to land before a segment is answered. onRequest runs on every request a bound peer sends, before reassembly and before the sms event:

import { isCommand, server } from '@larvit/smpp';

const knownRecipients = new Set(['46709771337']);

const { err } = await server({
	onRequest: async (session, pduObj) => {
		if (!isCommand(pduObj, 'submit_sm') || knownRecipients.has(pduObj.params.destination_addr)) {
			return false;
		}

		await session.sendReturn(pduObj, 'ESME_RINVDSTADR');

		return true;
	},
});
if (err) throw err;

• Return true: the hook answered the PDU and the library leaves it alone. false: the built-in handling runs.
• Every segment of a long message is a request of its own, so the hook sees each one.
• No bind reaches it, nor anything a peer sends before one: server() answers those and runs authenticate itself.
• A hook that throws or rejects reaches sessionError, and nothing is written for that request; the peer's own response timeout settles it. authenticate fails the same way, leaving the bind unanswered.
• enquire_link and unbind reach the hook too, and an unanswered enquire_link has the peer drop the link. Guard on the command name, as above, and a failing hook costs only its own request.
• A Session you construct yourself takes the same hook as a session option, and that is where a peer's bind gets accepted, since a hand-wired session has no bind handling of its own.

sendDlr() takes SCHEDULED, ENROUTE, DELIVERED, EXPIRED, DELETED, UNDELIVERABLE, ACCEPTED, UNKNOWN, REJECTED or SKIPPED. The first two go out as intermediate delivery notifications (esm_class 0x20), the rest as delivery receipts (0x04).

Bind direction

The three bind types are honoured in both directions, whichever end of the link the session is:

• session.sendSms() on a receiver-bound session, and sms.sendDlr() to a transmitter-bound peer, return err before anything reaches the wire.
• A submit_sm arriving on a receiver-bound session, or a deliver_sm on a transmitter-bound one, is answered ESME_RINVBNDSTS.
• data_sm carries a message either way, so which end the session is decides: a client refuses one on a transmitter bind, a server() session on a receiver bind. bindAllows('data_sm') answers for the inbound direction. A Session you construct yourself is the ESME end, as client() builds; a hand-wired SMSC sets session.linkEnd = 'smsc', as server() does.
• transceiver, the default, carries both. session.send() is a passthrough and is not checked.

Logging

log takes any object with debug, error, info, verbose and warn methods, each (msg: string, metadata?: Record<string, boolean | number | string>) => void. Message strings are static; every dynamic value is in the metadata, so entries group by message.

@larvit/log implements it as it stands:

import { Log } from '@larvit/log';
import { client } from '@larvit/smpp';

const { err, session } = await client({ log: new Log('debug') });

So does an object of your own:

const log = {
	debug:   () => undefined,
	error:   (msg, metadata) => { console.error(msg, metadata); },
	info:    (msg, metadata) => { console.info(msg, metadata); },
	verbose: () => undefined,
	warn:    (msg, metadata) => { console.warn(msg, metadata); },
};

SmppLog is the type.

PDUs and the low-level API

The codec is exported, synchronous, and never throws:

import { isCommand, objToPdu, pduToObj } from '@larvit/smpp';

const { err, pduObj } = pduToObj(buffer);
if (err) return;

if (isCommand(pduObj, 'submit_sm')) {
	pduObj.params.destination_addr; // typed as a string
}

Reading.

• params.short_message is decoded with the PDU's own data_coding; shortMessageOctets is that field as it arrived. Neither holds a body carried in the message_payload TLV, which a data_sm always uses.
• messageOctets(pduObj) is the one answer to which of the two the peer used, undecoded. decodeMessage(octets, pduObj.params.data_coding, pduObj.params.esm_class) turns them into text and hands back the UDH where the PDU carries one.
• concatOf(pduObj): the part, total and reference a PDU declares and the spelling that carried them, 'udh' or 'sar', or undefined for a whole message.
• messageClassOf(dataCoding): 0 for the flash class, 1, 2 and 3 for the ME-, SIM- and TE-specific ones, undefined where that data_coding's coding group carries no class.

Building.

• A string short_message or message_payload is encoded in the alphabet the PDU's data_coding names, detected from the text where you name none. One that alphabet cannot carry is refused, naming the character, its code point and where it is.
• A Buffer goes out exactly as given under any data_coding: binary payloads, hand-built user data headers, deliberately malformed bodies.
• session.send() and session.sendReturn() build through the same codec and refuse the same bodies.
• unencodable(message, encoding): { char, index } for the first character an alphabet cannot carry, undefined where it carries them all. The check sendSms() makes before encoding.
• dataCodingByEncoding[encoding]: the data_coding this library writes each alphabet under, which is what to put beside octets from encodeMessage().
• smppTime.encode(value) returns { err, text } for a validity_period or schedule_delivery_time; smppTime.decode(text) returns { err, date }.

Everything exported.

Sessions	client, server, Session, SmppServer
Codec	pduToObj, objToPdu, pduReturn, isCommand, isResp, PduFramer, PduRefusedError, maxPduLength, maxSeqNr
Messages	encodeMessage, decodeMessage, splitMessage, bitCount, messageOctets, concatOf, concatInfo, detect, unencodable, messageClassOf, dataCodingByEncoding, encodingByDataCoding
Receipts	dlrFromPdu, parseReceipt, receiptCodes
Time and ids	smppDate, smppTime, uuidv7
Spec tables	cmds, consts, encodings, errors, tlvs, types, the cmdsById, constsById, errorsById and tlvsById maps, and all of them grouped as defs. isCommandName, isErrorName, isEncodingName, commandNameById and errorNameById narrow a value into them.
Types	Every option, result, event payload and table entry has a named type: ClientOptions, ServerOptions, SendSmsOptions, SendSmsResult, Sms, Dlr, MessageDlr, Receipt, PduObject, PduHeader, SmppLog, Result and the rest in dist/index.d.ts.

Migrating from larvitsmpp 0.4.0

See MIGRATION.md.

Development

Everything runs in the container; nothing is installed on the host.

docker compose run --rm node npm install
docker compose run --rm node npm test                # lint, typecheck and tests
docker compose run --rm node npm run build
docker compose run --rm node npm run test:compiled   # what CI runs on older Node versions

Tests are TypeScript and run directly under Node's type stripping, so there is no build step in the development loop. CI compiles them and runs them on Node 18, every LTS above it, and current.

License

MIT