Add PDU framing and delivery receipt parsing

2026-08-25 16:31:27 +02:00
parent 649e93cdde
commit 1827ab5964
4 changed files with 436 additions and 0 deletions
@@ -0,0 +1,127 @@
+import assert from 'node:assert/strict';
+import test, { describe } from 'node:test';
+import { dlrFromPdu, parseReceipt, receiptCodes } from '../src/dlr.ts';
+import { objToPdu, pduToObj } from '../src/pdu.ts';
+import type { PduObject, TlvInput } from '../src/pdu.ts';
+
+const receiptText = 'id:0195f0c7 sub:001 dlvrd:001 submit date:2508251430 done date:2508251431 stat:DELIVRD err:000 text:hello';
+
+function deliverSm(message: string, tlvs?: Record<string, TlvInput>): PduObject {
+	const { buffer } = objToPdu({
+		cmdName: 'deliver_sm',
+		params: {
+			destination_addr: '46701113311',
+			esm_class: 4,
+			short_message: message,
+			source_addr: '46709771337',
+		},
+		seqNr: 1,
+		tlvs,
+	});
+
+	assert.ok(buffer);
+
+	const { pduObj } = pduToObj(buffer);
+
+	assert.ok(pduObj);
+
+	return pduObj;
+}
+
+describe('parseReceipt()', () => {
+	test('pulls every standard field out of the receipt body', () => {
+		const receipt = parseReceipt(receiptText);
+
+		assert.equal(receipt.id, '0195f0c7');
+		assert.equal(receipt.sub, 1);
+		assert.equal(receipt.dlvrd, 1);
+		assert.equal(receipt.submitDate, '2508251430');
+		assert.equal(receipt.doneDate, '2508251431');
+		assert.equal(receipt.stat, 'DELIVRD');
+		assert.equal(receipt.err, '000');
+		assert.equal(receipt.text, 'hello');
+	});
+
+	test('does not confuse "done date" with "submit date"', () => {
+		const receipt = parseReceipt(receiptText);
+
+		assert.notEqual(receipt.submitDate, receipt.doneDate);
+	});
+
+	test('leaves absent fields undefined rather than guessing', () => {
+		const receipt = parseReceipt('id:abc stat:UNDELIV');
+
+		assert.equal(receipt.id, 'abc');
+		assert.equal(receipt.stat, 'UNDELIV');
+		assert.equal(receipt.sub, undefined);
+		assert.equal(receipt.doneDate, undefined);
+	});
+});
+
+describe('dlrFromPdu()', () => {
+	test('prefers the TLVs when the peer sends them', () => {
+		const dlr = dlrFromPdu(deliverSm(receiptText, {
+			message_state: { tagId: 0x0427, tagValue: 5 },
+			receipted_message_id: { tagId: 0x001E, tagValue: 'from-the-tlv' },
+		}));
+
+		assert.ok(dlr);
+		assert.equal(dlr.smsId, 'from-the-tlv');
+		assert.equal(dlr.statusId, 5);
+		assert.equal(dlr.statusMsg, 'UNDELIVERABLE');
+	});
+
+	// 0.4.0 answered ESME_RINVTLVSTREAM unless both TLVs were present, so Kannel-style receipts —
+	// text only, no TLVs — were unusable.
+	test('falls back to the receipt text when there are no TLVs', () => {
+		const dlr = dlrFromPdu(deliverSm(receiptText));
+
+		assert.ok(dlr);
+		assert.equal(dlr.smsId, '0195f0c7');
+		assert.equal(dlr.statusMsg, 'DELIVERED');
+		assert.equal(dlr.statusId, 2);
+		assert.equal(dlr.errorCode, '000');
+		assert.equal(dlr.doneDate?.toISOString(), '2025-08-25T14:31:00.000Z');
+	});
+
+	test('maps every spec status code back to its message state', () => {
+		for (const [code, expected] of [
+			['DELIVRD', 'DELIVERED'],
+			['UNDELIV', 'UNDELIVERABLE'],
+			['EXPIRED', 'EXPIRED'],
+			['DELETED', 'DELETED'],
+			['ACCEPTD', 'ACCEPTED'],
+			['REJECTD', 'REJECTED'],
+			['ENROUTE', 'ENROUTE'],
+			['UNKNOWN', 'UNKNOWN'],
+		]) {
+			const dlr = dlrFromPdu(deliverSm(`id:x stat:${String(code)} err:0`));
+
+			assert.equal(dlr?.statusMsg, expected);
+		}
+	});
+
+	test('returns nothing when the PDU identifies no message', () => {
+		assert.equal(dlrFromPdu(deliverSm('just a normal sms')), undefined);
+	});
+
+	test('exposes the raw receipt alongside the resolved fields', () => {
+		const dlr = dlrFromPdu(deliverSm(receiptText));
+
+		assert.ok(dlr?.receipt);
+		assert.equal(dlr.receipt.sub, 1);
+		assert.equal(dlr.receipt.text, 'hello');
+	});
+});
+
+describe('receiptCodes', () => {
+	// 0.4.0 wrote stat:UNDELIVERABLE, which is not the spec's seven-character field.
+	test('are the seven-character codes the spec defines', () => {
+		assert.equal(receiptCodes.DELIVERED, 'DELIVRD');
+		assert.equal(receiptCodes.UNDELIVERABLE, 'UNDELIV');
+
+		for (const code of Object.values(receiptCodes)) {
+			assert.equal(code.length, 7);
+		}
+	});
+});
@@ -0,0 +1,87 @@
+import assert from 'node:assert/strict';
+import test, { describe } from 'node:test';
+import { PduFramer } from '../src/pdu-framer.ts';
+import { objToPdu } from '../src/pdu.ts';
+
+function pdu(seqNr: number): Buffer {
+	const { buffer } = objToPdu({ cmdName: 'enquire_link', seqNr });
+
+	assert.ok(buffer);
+
+	return buffer;
+}
+
+describe('PduFramer', () => {
+	test('yields nothing until a whole PDU has arrived', () => {
+		const framer = new PduFramer();
+		const whole = pdu(1);
+
+		framer.push(whole.subarray(0, 8));
+		assert.deepEqual(framer.next(), { pdus: [] });
+
+		framer.push(whole.subarray(8));
+		assert.deepEqual(framer.next(), { pdus: [whole] });
+	});
+
+	test('splits several PDUs delivered in one chunk', () => {
+		const framer = new PduFramer();
+
+		framer.push(Buffer.concat([pdu(1), pdu(2), pdu(3)]));
+
+		const { pdus } = framer.next();
+
+		assert.ok(pdus);
+		assert.equal(pdus.length, 3);
+		assert.deepEqual(pdus[2], pdu(3));
+	});
+
+	test('reassembles a PDU dribbled one octet at a time', () => {
+		const framer = new PduFramer();
+		const whole = pdu(42);
+
+		for (const octet of whole) {
+			framer.push(Buffer.from([octet]));
+		}
+
+		assert.deepEqual(framer.next(), { pdus: [whole] });
+		assert.equal(framer.buffered, 0);
+	});
+
+	test('keeps a trailing partial PDU buffered for the next chunk', () => {
+		const framer = new PduFramer();
+		const second = pdu(2);
+
+		framer.push(Buffer.concat([pdu(1), second.subarray(0, 4)]));
+
+		const first = framer.next();
+
+		assert.ok(first.pdus);
+		assert.equal(first.pdus.length, 1);
+		assert.equal(framer.buffered, 4);
+
+		framer.push(second.subarray(4));
+		assert.deepEqual(framer.next(), { pdus: [second] });
+	});
+
+	// 0.4.0 read a command length of 0 as "discard the buffer" and looped; anything absurd was
+	// simply trusted and allocated.
+	test('reports an impossible command length instead of trusting it', () => {
+		const zero = new PduFramer();
+		const huge = new PduFramer();
+
+		zero.push(Buffer.alloc(16));
+		assert.ok(zero.next().err instanceof Error);
+
+		huge.push(Buffer.from('ffffffff0000001500000000000000ff', 'hex'));
+		assert.ok(huge.next().err instanceof Error);
+	});
+
+	test('ignores empty chunks', () => {
+		const framer = new PduFramer();
+
+		framer.push(Buffer.alloc(0));
+
+		assert.equal(framer.buffered, 0);
+		assert.deepEqual(framer.next(), { pdus: [] });
+	});
+});