Operator-requested 2026-05-27: centralize the per-platform quirks that
had been accumulating across credential_service, sidecar, and platforms
into a single per-platform module so adding/updating quirks becomes
"edit one file."
**Layout**
services/platforms/
base.py PlatformInfo dataclass + module-default key
chains + shared helpers (str_id_value, str_field)
__init__.py PLATFORMS dict + public API (auth_type_for,
known_platform_keys, to_dict,
external_post_id_keys_for, description_keys_for)
patreon.py metadata only — the reference platform, no quirks
subscribestar.py metadata + augment_cookies (18+ agreement) +
derive_post_url (synthetic /posts/<post_id>)
hentaifoundry.py metadata + augment_cookies (host-only PHPSESSID
duplicate) + derive_post_url (/pictures/user/...)
pixiv.py metadata + derive_post_url (/artworks/<id>)
discord.py metadata + derive_post_url
(channels/<server>/<channel>/<message>)
deviantart.py metadata only — un-audited; quirks to be added
when an operator first exercises DA
**PlatformInfo extensions**
Existing fields preserved. Four new optional fields:
external_post_id_keys: tuple[str, ...] | None
Override the sidecar external_post_id lookup chain. None falls
back to DEFAULT_EXTERNAL_POST_ID_KEYS in base.py
("post_id", "id", "index", "message_id") — covers every current
platform.
description_keys: tuple[str, ...] | None
Override the description body lookup chain. None falls back to
DEFAULT_DESCRIPTION_KEYS ("content", "description", "caption",
"message") — Discord's "message" body field is covered by the
default's trailing entry.
derive_post_url: Callable[[dict], str | None] | None
Synthesize the post permalink from sidecar metadata. None = trust
the bare `url` / `post_url` field (patreon, deviantart).
subscribestar/pixiv/hf/discord override this because their `url`
is the file CDN URL.
augment_cookies: Callable[[str], str] | None
Post-process the materialized cookies.txt before gallery-dl
consumes it. None = no-op. Used by subscribestar (age cookie) and
hentaifoundry (host-only PHPSESSID duplicate).
**Consumer changes**
- credential_service._augment_cookies(platform, netscape) shrunk from a
per-platform-conditional dispatcher (~80 lines of inlined helpers) to
a 5-line lookup: `info.augment_cookies(netscape) if info and
info.augment_cookies else netscape`. The platform-specific helper
bodies moved verbatim into the per-platform modules.
- sidecar.parse_sidecar similarly delegates: external_post_id chain via
external_post_id_keys_for(category), description chain via
description_keys_for(category), post_url via
PLATFORMS[category].derive_post_url. The _DERIVED_URL_PLATFORMS set
and inline _derive_post_url body both gone. Added a shared `_first_id`
helper for bool-safe id coercion.
**Public API preserved**
PLATFORMS, PlatformInfo, auth_type_for, known_platform_keys, to_dict
are all re-exported from the package's __init__.py. test_platforms_registry
test_credential_service, and test_sidecar_util pass without changes
because the behavior is identical; only the implementation moved.
**Adding a new platform**
1. Create services/platforms/<name>.py with `INFO = PlatformInfo(...)`
and any of the four optional hooks.
2. Import it in services/platforms/__init__.py + add to the PLATFORMS
tuple-comprehension.
3. Done. sidecar parsing, cookie materialization, /api/platforms all
pick it up automatically.
Audit of one sample sidecar per platform on the operator's
/mnt/Data/Patreon/ archive surfaced three parser bugs that have been
silently corrupting non-Patreon Posts since FC-3 shipped:
1. SubscribeStar `id` vs `post_id` confusion. gallery-dl puts the
per-attachment id in `id` (e.g. 711509) and the actual post id in
`post_id` (e.g. 360360). FC's external_post_id chain had `id`
winning, so every multi-image SubscribeStar post was fragmented into
N Post rows in the database. Reorder the chain to
`("post_id", "id", "index", "message_id")` — Patreon/Pixiv (no
`post_id`), HF (uses `index`), Discord (uses `message_id`) all
unaffected.
2. Discord `message` field not captured. Discord posts put the body in
`message`, not `content`. Append it to the description fallback chain
`("content", "description", "caption", "message")`.
3. post_url is the file URL on SubscribeStar/Pixiv/HF/Discord. New
`_derive_post_url(platform, data)` helper synthesizes proper
permalinks from per-platform fields:
subscribestar → https://www.subscribestar.com/posts/<post_id>
pixiv → https://www.pixiv.net/artworks/<id>
hentaifoundry → https://www.hentai-foundry.com/pictures/user/<user>/<index>
discord → https://discord.com/channels/<server>/<channel>/<message>
Patreon's bare `url` IS a real permalink and is used as-is. For the
four file-URL platforms, the bare `url` is NEVER trusted: derive or
return None rather than persist a CDN URL.
Tests:
- `test_parse_core_fields_and_id_priority` flipped to assert post_id
wins over id.
- New `test_parse_id_used_when_no_post_id` covers the Patreon real
shape.
- New `test_parse_message_used_as_description_fallback` covers Discord
bodies.
- Five new tests cover per-platform post_url derivation
(SubscribeStar/Pixiv/HF/Discord/Patreon-untouched + missing-fields →
None).
Cleanup migration alembic 0025_fix_subscribestar_post_ids:
- For each SubscribeStar Post: find a related ImageRecord.path, walk to
its sidecar JSON, read `post_id`, overwrite Post.external_post_id +
post_url with the corrected values.
- After all updates, every group of Posts under one source sharing the
same NEW external_post_id is a fragment-set — merge to a canonical
row using the same ImageProvenance pre-delete + repoint dance as
alembic 0022 (banked pattern).
- Pure-SQL backfill of Pixiv post_url: replace any `i.pximg.net`-shape
url with the derived `/artworks/<id>` permalink.
- HF and Discord post_url backfills skipped — HF would need the `user`
field (not stored on Post), Discord needs server/channel triple.
Both will be corrected by a deep-scan re-applying sidecars through
the new parser.
Idempotent: re-running on already-corrected data is a no-op.
SubscribeStar gallery-dl always writes `title: ""` and embeds the leading
sentence inside `content` HTML. Confirmed against the operator's
/mnt/Data/Patreon/Cheunart/subscribestar/ dump 2026-05-27: every
post's JSON has `title: ""` and a content like
`<div>Lets say hello to you guys with my Belle <br><br><br></div>`.
FC's sidecar parser, treating empty strings as missing, had been leaving
post_title NULL on every subscribestar post since FC-3 shipped.
Fix at two layers:
1. `backend/app/utils/sidecar.py` — new `_first_line_text(body, limit)`
helper strips HTML tags, collapses whitespace, returns the first
non-empty line truncated to 120 chars with ellipsis. `parse_sidecar`
now falls back to this when `title` resolves to None and a
`content`/`description`/`caption` value is present. Patreon's
non-empty titles short-circuit the fallback so existing behavior is
unchanged. Four new tests in test_sidecar_util.py pin: derivation
from content, truncation at 120 chars, explicit-title precedence,
no-content no-fallback.
2. `alembic 0024_backfill_post_title_from_description` — backfills the
same logic across existing Post rows where `post_title IS NULL OR
post_title = ''` AND description is present. Idempotent (re-running
is a no-op once titles are populated). Downgrade is a no-op since
there's no safe way to tell derived rows from genuine ones.
After deploy + migration: subscribestar posts will surface a meaningful
title in PostCard, post feed search, etc.
The two prefix-parsing tests were pinned to `artist:Eric`, but `artist`
was removed from KNOWN_KINDS in commit 4cad07a (provenance is a separate
axis from tags). The parser now keeps `artist:` literal, so the assertion
`body["name"] == "Eric"` failed.
Repointed to `character:Saber` (still in KNOWN_KINDS). Also updated the
stale `artist:` docstring example in parse_kind_prefix to `fandom:`.
Caught by [[reference-grep-pinned-tests-in-plans]] — should have grep'd
tests/ for `artist:` when shrinking KNOWN_KINDS. Banking the miss.
slugify() produces ASCII-only lowercase slugs from arbitrary text (used for
artist slugs and tag slugs). paths.derive_subdir/derive_top_level_artist
extract the destination layout and folder→artist convention from an import
source path. hash_suffixed_name builds IR-style 'stem__hash10.ext' filenames.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen