Files
dragonsstash/worker/src/archive/forward-identity.ts
T

34 lines
1.4 KiB
TypeScript

import { createHash } from "crypto";
import { crcFingerprint } from "./fingerprint.js";
import type { FileEntry } from "./zip-reader.js";
/**
* Derive a Package.contentHash-compatible identity string for a forward-path
* package (no downloaded bytes exist to hash directly). Priority order:
* 1. A CRC32-fingerprint hash, when the ranged listing's CRCs are complete
* (ZIP/RAR today) — the strongest available signal, since it lets
* forward-path and download-path copies of the same archive still
* collide/dedupe on identical content.
* 2. TDLib's remote.unique_id, when CRCs are incomplete (7z today has none).
* 3. sourceChannelId+sourceMessageId, as a last-resort unique value so the
* required-unique Package.contentHash column is always satisfiable.
* Follows the same `<prefix>:<value>` synthetic-hash convention already used
* by `rebuild.ts`'s `rebuild:${destChannelId}:${destMessageId}` placeholder.
*/
export function deriveForwardContentHash(
entries: FileEntry[],
remoteUniqueId: string | null,
sourceChannelId: string,
sourceMessageId: bigint,
): string {
const fp = crcFingerprint(entries);
if (fp.complete && fp.crcs.length > 0) {
const hash = createHash("sha256").update(fp.crcs.join(",")).digest("hex");
return `fingerprint:${hash}`;
}
if (remoteUniqueId) {
return `forward:${remoteUniqueId}`;
}
return `forward:${sourceChannelId}:${sourceMessageId}`;
}