smpp-js/todo.md

todo.md

Remaining work for the @larvit/smpp 1.0.0 rewrite. Read AGENTS.md first — the goals and hard rules there constrain every item below.

This is a temporary working file: it is deleted when 1.0.0 ships, and until then it sets its own rules. The documentation conventions in AGENTS.md do not govern it, and nothing here is a source anything else may cite.

Status

The rewrite is feature complete and green: the suite, lint and typecheck are clean on Node 18, 20, 22 and 24. What is left is release work and a few things worth adding before or after 1.0.0.

The agreed API

Settled with the maintainer before implementation. Do not change any of it without asking. The public surface is documented in README.md; this is the short form.

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

const { err, session } = await client({ host, password, port, username });
const { err: sendErr, pduObjs, smsIds } = await session.sendSms({ dlr, from, message, to });
await session.unbind();

const { err: serverErr, server: smpp } = await server({ authenticate, port });
smpp.on('session', session => {
	session.on('sms', async sms => {
		await sms.sendResp();
		if (sms.dlr) await sms.sendDlr('DELIVERED');
	});
});
await smpp.close();

Rules the API follows:

• Never throws. Everything fallible resolves to { err?, … }. See AGENTS.md rule 1.
• Named exports only, no default export. defs is exported as a group alongside the individual tables.
• The PDU codec is synchronous and returns { err?, pduObj? } / { err?, buffer? }.
• Low-level surface stays public, including session.sock, session.send() and session.sendReturn().

Done

	Covered by
Definition tables: constants, errors, encodings, wire types, TLVs, commands	test/encodings.test.ts, test/types.test.ts, test/commands.test.ts
Message helpers: splitting, bit counting, SMPP dates and times	test/message.test.ts
PDU codec: parse, build, respond, per-command typing, bounds checks	test/pdu.test.ts
Stream framing	test/pdu-framer.test.ts
Delivery receipt parsing, TLV and text	test/dlr.test.ts
Session, client, server: bind, auth, send, reassembly, DLRs, timeouts, abort, send window	test/session.test.ts
Merged multipart DLRs including across a reconnect, reassembly bounds, per-send abort, the segment cap	test/session-extras.test.ts
smsIdFormat: a peer's submit_sm_resp and receipt ids read into one notation before they are compared	test/dlr.test.ts, test/session-extras.test.ts
A draining close() and unbind(), bounded by shutdownTimeout or an abort	test/session-extras.test.ts
A drain that also waits out the messages the application has not answered, with sendDlr() the one send that passes it	test/session-extras.test.ts
OutgoingRequests: the gate, the window, the pending map and the retry under one owner, told when a link comes up or goes down	test/session-extras.test.ts, test/session.test.ts
Held messages capped and expiring, so an application that answers nothing cannot grow them	test/session-extras.test.ts
A send with no link held for the next one, and one the link dropped under counted as unanswered	test/session-extras.test.ts
A message whose link dropped refused an answer, with its receipt still allowed out	test/session-extras.test.ts
The hold released exactly when the peer was answered: a refused sendResp() keeps it, a listener that rejected drops it	test/session-extras.test.ts
Every runnable README example	test/readme.test.ts
Receipt-versus-message classification by esm_class	test/dlr.test.ts, test/session.test.ts
An intermediate delivery notification read as a report marked intermediate, as is a receipt reporting ENROUTE or SCHEDULED, and never counted into a merge	test/dlr.test.ts, test/session.test.ts, test/session-extras.test.ts
A transient state sent under the marker the spec gives it, off the same list the reader uses	test/session-extras.test.ts
A listener that throws, or rejects, reaching sessionError/serverError rather than the process	test/session.test.ts, test/error-from.test.ts
Cross-checked against node-smpp both ways and over a live session	test/interop.test.ts
CI on Node 18/20/22/24, Renovate, tag-triggered publish	.github/workflows/

Every defect listed in the AGENTS.md table has a regression test naming the behaviour.

The GitHub backlog, once this branch is main

Nothing below is closed while the default branch is still 0.4.0 — declining a security bump on a live default branch is worse than leaving it open. Work through this immediately after the rename.

Close as fixed by 1.0.0, naming the replacement in the comment:

	Fixed by
#4 DLR errors with message_state missing	dlrFromPdu() parses the stat: receipt text when the TLVs are absent
#33 Large inbound text arrives as raw Buffer segments	IncomingRequests reassembles a UDH-carrying deliver_sm into one sms event
#3 Tests for flash messages	test/session.test.ts
#20 Tests fail on current dependency versions	The mocha suite is gone; node:test on Node 18/20/22/24
#2 Tests for the README examples	test/readme.test.ts
#17 addr_ton/addr_npi should be settable	sendSms() takes all four, documented and tested
#16 Support all three bind types	Bound and enforced in both directions
#13 Limit a long SMS to fewer segments	The maxSegments send option
#68 message_id in submit_sm_resp, spec DLR codes	All four hold: sendResp() always answers a message_id, per segment; stat:UNDELIV is the 7-character code. Credit the reporter — the fork found real defects.

Close as superseded, all against 0.4.0 dependencies the rewrite does not have — async, coveralls, eslint, iconv-lite, larvitutils, mocha, mocha-eslint, portfinder, uuid: #40, #41, #42, #45, #46, #47, #59, #63, #64, #65, #67, #70. #70 is the open uuid advisory GitHub reports on the default branch; it disappears with the runtime dependencies rather than being fixed.

#60 is Renovate's dashboard — leave it, it re-baselines itself against the new package.json.

Leave open: #8, the socket's remote host and port on log messages. Only server - incoming connection carries them today; putting them on every session message is a change to every call site.

Before publishing 1.0.0

• Create the @larvit/smpp package on npm and add NPM_TOKEN to the repository secrets, which .github/workflows/release.yaml needs.
• Decide whether smsIds should be (string | undefined)[]. An SMSC that names an id for the first segment of a concatenated message only — Telesign documents exactly that — leaves the rest empty, so string[] promises what the value does not keep: taking the first id, or building a map from the array, compiles and then misbehaves, and an empty string collides with another message's in a correlation table. The cost is that every consumer narrows, including the majority whose SMSC always names an id. Raised by the phase 11 product review, 2026-09-08. This one is 1.0.0-or-never — after release it needs a major version.
• A default GSM send declares IA5, not GSM 03.38. dataCodingFor() resolves encoding through consts.ENCODING, so 'ASCII' goes out as data_coding 0x01 — SMPP 3.4 5.2.19's IA5 (CCITT T.50)/ASCII — while the codec writes the GSM 03.38 table, where @ is 0x00 and $ is 0x02 against IA5's NUL and STX. encodingByDataCoding() reads 0x00 back as GSM 03.38, so this library's writer and reader disagree, and every peer in interop-tests/ submits GSM text at data_coding 0. Nothing asserts what our own default send declares, and the echo tests use characters where the two tables agree, which is why the suite is green. test/message-class.test.ts pins the current value. Goal 1 owns it. The fix is a three-entry map in send-sms.ts (ASCII → 0x00, LATIN1 → 0x03, UCS2 → 0x08) rather than any move of a published constant — consts.ENCODING.ASCII = 0x01 is a correct name for SMPP's flat-table IA5 entry, and the defect is using that group as the option's vocabulary. Which value an operator should see is the maintainer's call, and it wants an interop-tests/ run. Raised by the architecture review of #99, 2026-09-09.
• Tag v1.0.0 to publish.
• npm deprecate larvitsmpp pointing at @larvit/smpp. Maintainer's call to run it; not something CI should do.
• Rename the branches, once everything above is done. Maintainer's call, 2026-09-04: master becomes v0.4.0, typescript becomes main, and main is the repository's default branch. Renaming rather than merging is what the orphan commit leaves available — the two histories share no ancestor, so a merge refuses them outright. - [ ] Rename master to v0.4.0. - [ ] Rename typescript to main, and make it the default branch. - [ ] Retarget what still points at an old name: #71, and the open PRs based on master, which a rename carries over rather than closes. - [ ] Delete rewrite-base once #71 is resolved; it exists only to give that PR a reviewable diff.

Worth doing, not blocking

• A send the codec will refuse waits for a link and a window slot first. refuse() in outgoing-requests.ts runs misuse() and the abort check before the wait, precisely so a call that can never go out does not queue for what it will never use; a body objToPdu() refuses on every attempt is the same case, and #98 made it a common one. On a down link the caller waits responseTimeout and is told the link failed rather than that the body could not be built — goal 2's wrong answer about what happened. The cheap fix builds the PDU twice, so the shape is the open half. Raised by the architecture review of #98, 2026-09-09.

• message.ts answers two questions. Message coding and the SMPP time format (smppDate, smppTime) share the file, which the architecture map in AGENTS.md already spells out as four concerns. Nothing is wrong today; if the file has to move for another reason, smpp-time.ts is the split. Raised by the architecture review of #98, 2026-09-09.

• A gate that refuses a floating version anywhere in the repo. Maintainer's ask on #71, 2026-09-06, on the release.yaml pinning thread, which stays open until this lands. Pinning every action and runner by hand is what the ask followed; the gate is what keeps them pinned. It has to cover workflow uses: and runs-on:, compose image:, and Dockerfile FROM, and the conventions differ per kind — actions take a semver tag, images the full patch version — so one grep for latest is not it.

• A gate that fails when the test matrix misses the current Node. Maintainer's ask on #71, 2026-09-06, on the Node 26 thread, which stays open until this lands. Node 26 was added by hand; nothing notices when 27 ships. Needs a source for what Current is — the Node release schedule is published as JSON — and a decision on whether a new Current fails the build or opens a PR, which is what Renovate already does for everything else here.

• Group the session's collaborators under src/session/. session.ts imports dlr-merger, incoming-requests, link-timers, outgoing-requests, pdu-transport, reconnect-loop and send-sms, and nothing else does, so the directory would make that boundary visible. The OutgoingRequests extraction this was to be done with landed on 2026-09-01, so it is the remaining half. Raised by review, 2026-09-01.

• leftOf() and the link gate's own budget are one concept counted twice. idle-waiters.ts reads what is left of a budget as Math.max(1, deadline - now), because 0 means "forever" there; link-gate.ts runs the same subtraction and calls <= 0 expired. Neither is reachable from the other, so nothing can disagree today, but a reader who learns one and applies it to the other is wrong. A budget type both take would close it. Raised by review, 2026-09-01.

• err: on a receipt for a state that neither delivered nor failed. receiptText() now writes err:000 for DELIVERED and for the two transient states, and err:001 for every other — so ACCEPTED, SKIPPED, UNKNOWN and DELETED still announce an error code the SMSC never had. Which of those are failures is the open half. Raised by review, 2026-09-03; needs a decision.

• once() is copied into four test files, and two copies never give up. session-extras.test.ts and readme.test.ts reject after 5000 ms; session.test.ts and tls.test.ts wait forever, so an event that never fires still hangs the run the way an unclosed listener used to. One shared, guarded copy closes the rest of that class.

• A peer whose message ids share one base logs a refused merge on every send. smsc01-000123 and smsc01-000124 carry the same base, so DlrMerger merges the first message and refuses every one after it, one log line per send. Left at info — nothing the operator can fix is wrong — but a rate guard or silence may suit it better. Raised by review, 2026-08-30.

• submit_multi and the broadcast commands encode and decode, but nothing exercises them end to end. The interop suite is the natural place.

• Move to TypeScript 7 once typescript-eslint supports it; renovate.json pins TypeScript below 6.1 for exactly that reason.

• Coverage reporting. node --test --experimental-test-coverage works today; nothing publishes the numbers.

• An onReceipt hook. Receipt text is only loosely specified and operators disagree on it, but dlrFromPdu() is wired into IncomingRequests with no seam of its own: an application facing a format we do not parse has to take the whole PDU on onRequest and reimplement the dispatch, which owns the response as well. Mirror the onRequest seam — return a Dlr to own the receipt, undefined to fall through to the built-in parser.

Declined

• Merge state surviving a process restart. Declined by AGENTS.md goal 7, maintainer's call, 2026-09-02. A restart loses every incomplete receipt group and a peer has no reason to resend one it already had answered, so the loss is real — but surviving it means handing the application the merge state to persist, which the scope floor covers as squarely as holding the state here would, and which publishes the shape of DlrMerger's groups against goal 6. Nothing is foreclosed: the seam can still be added after 1.0.0 as a minor.

• Throughput throttling — a TPS cap, and backing off on ESME_RTHROTTLED. Declined by AGENTS.md goal 7: an operator's rate limit is scoped to the account, while the widest thing this library owns is a session, so a bucket here cannot see a second process binding the same account and is wrong in exactly the case it exists for. sendSms() surfaces ESME_RTHROTTLED to the caller instead, and maxOutstanding stays — a window slot frees on the peer's next response, which is self-limiting in a way a rate ceiling is not.