Posting an external URL used to skip the torrent/webseed benefit entirely. Now the
upload modal's external tab auto-derives a WebTorrent webseed from the URL at
publish time: fetch the remote file (CORS-permitting), stream it under a hard size
cap, compute the infoHash, and publish a magnet with the URL as the webseed (ws=).
Best-effort — CORS failure / over the cap / any error silently degrades to
URL-only. Only runs when the user didn't paste their own magnet.
- js/utils/externalUrlTorrent.js: fetchBlobWithCap (streams with a 500 MB cap,
aborts past it, short-circuits on content-length), buildWebseedMagnet, and
deriveExternalUrlTorrent (reuses createTorrentMetadata). Pure + injectable → unit
tested without network/WebTorrent.
- mediaUploader.deriveTorrentForExternalUrl: derives the ws= magnet and, when
storage is unlocked, also hosts the tiny .torrent so the webseed can actually
bootstrap P2P (xs=) — best-effort, falls back to ws=-only.
- UploadModal.handleExternalFlow calls it; deriveExternalWebseed only hosts the
.torrent when storage is unlocked, shows progress on the submit button, and
never throws.
Tests: tests/external-url-torrent.test.mjs (9 — magnet assembly, name parsing,
streamed size-cap enforcement + short-circuit, fetch-failed, derive-with-injected-
hash, failure propagation). Lint + build green.
Next: the same for editing a URL in the Edit modal.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
