New iTunes Link tab between Deezer Link and YouTube. Accepts album,
track, and playlist URLs from music.apple.com / iTunes. Pulls the
tracklist, runs it through the same discovery -> sync -> download
pipeline as the other link tabs.
Apple Music playlists go through amp-api with a Bearer JWT scraped
from the SPA. The legacy meta-tag and inline `"token":"..."` paths
are gone in the current music.apple.com SPA, so the extractor now
walks the page's `<script src>` list (prioritising index/chunk/main
bundles), fetches up to 8 JS bundles, regex-matches JWT-shaped
strings, and base64-decodes each payload to confirm it carries
Apple media-api claims (`root_https_origin`, or `iss + iat + exp`)
before trusting it. Filters out analytics / error-reporter JWTs that
also ship in the bundle.
Tokens are cached at module scope for 6h behind a threading.Lock so
the three-worker discovery executor doesn't thunder-herd Apple on
cold start, and amp-api calls go through a single helper that on
401 invalidates the cache, refetches the page, force-refreshes the
token, and retries the request once. The playlist fetcher memoises
the page HTML for the cache-miss path so we don't refetch it for
every paginated `/tracks` page.
spotify_public discovery worker accepts the new platform shape so
iTunes Link reuses the same matching code path as Deezer Link and
Spotify-public. UI bits live in the sync-services.js iTunes Link
tab, with platform plumbing through wishlist-tools.js for the
multi-source state map.
Fifth lift in the PR5 discovery-workers series. Pulls the 278-line
public-Spotify-link discovery worker out of `web_server.py` into its
own focused module under `core/discovery/`. Pure 1:1 lift — wrapper
keeps the original entry-point name.
What the Spotify Public discovery worker does:
1. Pause enrichment workers (release shared resources).
2. For each track:
- Cancellation gate (state['cancelled']).
- Normalize artists to plain string list (handles dict + str inputs).
- Discovery cache lookup; cache hit short-circuits the search and
populates display fields from the cached match.
- SimpleNamespace duck-type → `_search_spotify_for_tidal_track`
(shared search helper, returns tuple for Spotify or dict for iTunes).
- On Spotify match: build `match_data` preserving track_number /
disc_number from raw API data; image extracted from album images
or track object fallback; release_date filled from track.release_date
when album dict is missing it.
- On iTunes match: dict result → match_data with source set to
discovery_source; image extracted from album images.
- Save matched result to discovery cache.
- On miss: Wing It stub stored as 'wing-it' status.
3. After all tracks: phase='discovered', activity feed entry.
4. On error: state['phase']='error' + status with error string.
5. Finally: resume enrichment workers.
This worker is structurally close to the Deezer worker (see PR5d) but
intentionally diverges on:
- Track-data field names (`spotify_public_track` vs `deezer_track`).
- Artist normalization (Spotify Public can pass dicts or strings).
- No mirrored-playlist DB writeback (sync is handled separately).
Dependencies injected via `SpotifyPublicDiscoveryDeps` (12 fields) —
spotify_public_discovery_states, spotify_client, plus 10 callable
helpers (pause/resume enrichment, get_active_discovery_source,
get_metadata_fallback_client, get_discovery_cache_key, get_database,
validate_discovery_cache_artist, search_spotify_for_tidal_track,
build_discovery_wing_it_stub, add_activity_item).
Diff vs original after `deps.X` → global X normalization is **zero
differences** — 278 lines orig = 278 lines lifted, byte-identical body
(including all whitespace, comments, log strings).
Tests: 10 new under tests/discovery/test_discovery_spotify_public.py
covering cache hit short-circuit, dict-artist normalization, Spotify
tuple match (track/disc preservation), iTunes dict match path, Wing It
fallback, cancellation, completion phase update, activity feed entry,
top-level error handler, per-track error handling.
Full suite: 1118 passing (was 1108). Ruff clean.
