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Decode a receipt body before reading it and stop an unnameable state TLV overriding it

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This commit is contained in:
Lilleman auf Larv
2026-08-27 16:08:54 +02:00
parent 4c08fe8fa3
commit b9f77ec969
9 changed files with 102 additions and 49 deletions
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src/dlr.ts
+36 -17
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@@ -2,6 +2,8 @@ import type { MessageState } from './defs/constants.ts';
import type { ParamValue } from './defs/types.ts';
import type { PduObject } from './pdu.ts';
import { consts, constsById } from './defs/constants.ts';
import { decodeMessage } from './message.ts';
import { paramNumber, paramText } from './defs/types.ts';
/**
* The seven-character status codes carried in a receipt's `stat:` field, mapped to the
@@ -49,7 +51,7 @@ export type Dlr = {
receipt: Receipt | undefined;
smsId: string | undefined;
statusId: number;
statusMsg: string;
statusMsg: MessageState;
};
const field = (name: string) => new RegExp(`\\b${name}:([^ ]*)`, 'i');
@@ -127,15 +129,25 @@ const messageTypeBits = 0x3c;
type MessageType = 'other' | 'receipt' | 'unmarked';
function messageType(pduObj: PduObject): MessageType {
const esmClass = pduObj.params.esm_class;
if (typeof esmClass !== 'number') return 'unmarked';
const type = esmClass & messageTypeBits;
const type = paramNumber(pduObj.params.esm_class, 0) & messageTypeBits;
if (type === consts.ESM_CLASS.MC_DELIVERY_RECEIPT) return 'receipt';
if (type !== 0) return 'other';
return type === 0 ? 'unmarked' : 'other';
return pduObj.tlvs.receipted_message_id === undefined ? 'unmarked' : 'receipt';
}
/** A UDH-carrying short_message reaches here as a buffer, header and all. */
function receiptBody(pduObj: PduObject): string {
const message = pduObj.params.short_message;
if (!Buffer.isBuffer(message)) return paramText(message);
return decodeMessage(
message,
paramNumber(pduObj.params.data_coding, 0),
paramNumber(pduObj.params.esm_class, 0),
).message;
}
function receiptId(tlvId: ParamValue | undefined, receipt: Receipt | undefined): string | undefined {
@@ -144,32 +156,39 @@ function receiptId(tlvId: ParamValue | undefined, receipt: Receipt | undefined):
return receipt?.id === '' ? undefined : receipt?.id;
}
function isMessageState(name: string | undefined): name is MessageState {
return name !== undefined && name in consts.MESSAGE_STATE;
}
/** The state TLV wins where it names a state we know; an unnameable one leaves the body to say. */
function receiptStatus(
tlvState: ParamValue | undefined,
receipt: Receipt | undefined,
): { statusId: number; statusMsg: string | undefined } {
if (typeof tlvState === 'number') {
return { statusId: tlvState, statusMsg: constsById.MESSAGE_STATE?.[tlvState] };
): { statusId: number; statusMsg: MessageState | undefined } {
const scraped = receiptStates[receipt?.stat?.toUpperCase() ?? ''];
if (typeof tlvState !== 'number') {
return { statusId: consts.MESSAGE_STATE[scraped ?? 'UNKNOWN'], statusMsg: scraped };
}
const state = receiptStates[receipt?.stat?.toUpperCase() ?? ''];
const named = constsById.MESSAGE_STATE?.[tlvState];
return { statusId: consts.MESSAGE_STATE[state ?? 'UNKNOWN'], statusMsg: state };
return { statusId: tlvState, statusMsg: isMessageState(named) ? named : scraped };
}
/**
* Builds a delivery report from a deliver_sm, or nothing if the PDU carries a message rather than a
* receipt. `esm_class` decides that where the peer sets a message type; where it sets none, the body
* is read for the standard receipt fields, which is the only thing Kannel and several other SMSCs
* send. The message_state and receipted_message_id TLVs are authoritative over the body.
* receipt. `esm_class` decides that where the peer names a message type and a receipted_message_id
* TLV where it names none; failing both, the body is read for the standard receipt fields, which is
* the only thing Kannel and several other SMSCs send.
*/
export function dlrFromPdu(pduObj: PduObject): Dlr | undefined {
const type = messageType(pduObj);
if (type === 'other') return undefined;
const message = pduObj.params.short_message;
const receipt = typeof message === 'string' ? parseReceipt(message) : undefined;
const body = receiptBody(pduObj);
const receipt = body === '' ? undefined : parseReceipt(body);
const smsId = receiptId(pduObj.tlvs.receipted_message_id?.tagValue, receipt);
const { statusId, statusMsg } = receiptStatus(pduObj.tlvs.message_state?.tagValue, receipt);