refactor(plex): extract img/subtitle/rollup helpers into app/plex services

R12 S1 step A. Move the pure, leaf-level helpers out of the 2227-line
routes/plex.py into the app/plex service package with public names:

- app/plex/imgcache.py — on-disk poster/art cache + proxy (was _img_cache_*,
  _image_key, _img_response, _IMG_CACHE/_IMG_SIZES). Owns the shared cache dir.
- app/plex/subtitles.py — WebVTT convert/time-shift + subtitle cache (was
  _srt_to_vtt, _shift_vtt, _ffmpeg_to_vtt, _sub_cache_*, _BITMAP_SUBS).
- app/plex/rollup.py — show watch-state aggregation (was _rollup,
  _show_status, _show_agg_subq, _show_state_map).

Behaviour-equivalent move: bodies verbatim, only the public API renamed and
call sites re-qualified. No endpoint or SQL change (db.query kept as-is; the
2.0 select() conversion is a later step). plex.py 2227 -> 2011 lines.

Gate: ruff clean, pytest 193 passed (pure-logic + DB lane).
This commit is contained in:
2026-08-11 21:16:44 +02:00
parent 2671ab4cc8
commit 4106bceb08
4 changed files with 272 additions and 245 deletions
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"""Thin on-disk cache + proxy helpers for Plex poster/art images.
Posters/art/cast-photos are proxied on demand; without a cache every scroll re-hits Plex over the
LAN (janky). We cache the fetched bytes on local disk keyed by a stable id, so repeat views (and
other users) serve instantly from disk. On-demand + bounded by the library size; no eviction (a
few hundred MB at most for a big library — acceptable, matching the download disk trade-offs).
`CACHE_DIR` is the shared Plex on-disk cache root; converted subtitle VTTs live here too
(see ``subtitles.py``).
"""
from pathlib import Path
from fastapi import Response
from sqlalchemy.orm import Session
from app.config import settings
from app.models import PlexCollection, PlexItem, PlexSeason, PlexShow
CACHE_DIR = Path(settings.download_root) / ".plex-img-cache"
_EXT_CT = [("jpg", "image/jpeg"), ("png", "image/png"), ("webp", "image/webp")]
_CT_EXT = {ct: ext for ext, ct in _EXT_CT}
# Target box per variant — Plex resizes to these server-side. Posters fill ≤176px cells (grid/info/
# strips), so 400px covers 2× DPR; the faint backdrop art only needs ~1280px. Keeps images ~tens of KB.
SIZES = {"thumb": (400, 600), "art": (1280, 720)}
def key_for(db: Session, rating_key: str, variant: str) -> str | None:
"""The stored Plex image path for a known rating_key (item/show/season). Only mirrored keys
are proxyable — this is not an open image proxy."""
it = db.query(PlexItem).filter_by(rating_key=rating_key).first()
if it is not None:
return it.art_key if variant == "art" else it.thumb_key
sh = db.query(PlexShow).filter_by(rating_key=rating_key).first()
if sh is not None:
return sh.art_key if variant == "art" else sh.thumb_key
se = db.query(PlexSeason).filter_by(rating_key=rating_key).first()
if se is not None:
return se.thumb_key
col = db.query(PlexCollection).filter_by(rating_key=rating_key).first()
if col is not None:
return col.thumb_key
return None
def read(key: str) -> tuple[bytes, str] | None:
for ext, ct in _EXT_CT:
p = CACHE_DIR / f"{key}.{ext}"
try:
if p.exists() and p.stat().st_size > 0:
return p.read_bytes(), ct
except OSError:
pass
return None
def write(key: str, data: bytes, ct: str) -> None:
ext = _CT_EXT.get((ct or "").split(";")[0].strip(), "jpg")
try:
CACHE_DIR.mkdir(parents=True, exist_ok=True)
tmp = CACHE_DIR / f"{key}.{ext}.tmp"
tmp.write_bytes(data)
tmp.replace(CACHE_DIR / f"{key}.{ext}") # atomic publish
except OSError:
pass # cache is best-effort
def response(data: bytes, ct: str) -> Response:
return Response(content=data, media_type=ct, headers={"Cache-Control": "public, max-age=86400"})
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"""Roll a show's episodes up into a single watch-state (new | in_progress | watched) + on-deck.
Drives the show/season grid badges and the Resume / Play-from-start / mark-all buttons.
"""
from sqlalchemy import and_, case, func, or_
from sqlalchemy.orm import Session, aliased
from app.models import PlexItem, PlexState
def show_status(total: int, watched: int, inprog: int) -> str:
"""Roll a show's episodes up into a single watch state: fully watched, partially started, or new."""
if total and watched >= total:
return "watched"
if (watched or 0) > 0 or (inprog or 0) > 0:
return "in_progress"
return "new"
def rollup(cards: list[dict]) -> dict:
"""From ORDERED episode cards → the aggregate watch status, the "on deck" episode to Resume (the
last in-progress one, else the first unwatched), the first episode (for Play from the start), and
the episode count. Drives the show/season Resume + Play + mark-all buttons."""
total = len(cards)
watched = sum(1 for c in cards if c.get("status") == "watched")
inprog = [c for c in cards if (c.get("position_seconds") or 0) > 0 and c.get("status") != "watched"]
resume = None
if inprog:
resume = inprog[-1] # continue the latest-started episode
else:
resume = next((c for c in cards if c.get("status") != "watched"), None)
return {
"status": show_status(total, watched, len(inprog)),
"resume": resume,
"first": cards[0] if cards else None,
"episode_count": total,
}
def agg_subquery(db: Session, user_id: int):
"""Per-show episode counts for a user: total, watched, in-progress. Reused to (a) filter the show
grid by aggregate watch-state and (b) compute each card's badge."""
ps = aliased(PlexState)
return (
db.query(
PlexItem.show_id.label("show_id"),
func.count(PlexItem.id).label("total"),
func.count(case((ps.status == "watched", 1))).label("watched"),
func.count(
case(
(
and_(ps.position_seconds > 0, or_(ps.status.is_(None), ps.status != "watched")),
1,
)
)
).label("inprog"),
)
.outerjoin(ps, and_(ps.item_id == PlexItem.id, ps.user_id == user_id))
.filter(PlexItem.kind == "episode", PlexItem.show_id.isnot(None))
.group_by(PlexItem.show_id)
)
def state_map(db: Session, user_id: int, show_ids: list[int]) -> dict[int, str]:
if not show_ids:
return {}
rows = agg_subquery(db, user_id).filter(PlexItem.show_id.in_(show_ids)).all()
return {r.show_id: show_status(r.total, r.watched, r.inprog) for r in rows}
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"""WebVTT conversion, HLS-clock time-shift, and on-disk cache for Plex subtitle streams.
Text subtitles (embedded or external) are turned into WebVTT so the browser <track> can render them;
bitmap subtitles (Blu-ray/DVD) can't be (would need burn-in). Converted VTTs are cached on the shared
Plex on-disk cache root (``imgcache.CACHE_DIR``).
"""
import re
import subprocess
from app.plex.client import PlexError
from app.plex.imgcache import CACHE_DIR
# Image-based subtitle codecs (Blu-ray/DVD) — can't be turned into text WebVTT (would need burn-in).
BITMAP_SUBS = {"pgs", "hdmv_pgs_subtitle", "dvd_subtitle", "dvdsub", "vobsub", "dvbsub", "dvb_subtitle"}
def srt_to_vtt(text: str) -> str:
"""Minimal SubRip→WebVTT: add the header and switch the ms separator (`,`→`.`). SRT cue-index
lines are valid in WebVTT, so they're left as-is."""
body = re.sub(r"(\d\d:\d\d:\d\d),(\d\d\d)", r"\1.\2", text.replace("\r\n", "\n").lstrip(""))
return "WEBVTT\n\n" + body.strip() + "\n"
def _vtt_ts_to_s(ts: str) -> float:
parts = ts.split(":")
h = "0" if len(parts) == 2 else parts[0]
m, rest = parts[-2], parts[-1]
sec, _, ms = rest.partition(".")
return int(h) * 3600 + int(m) * 60 + int(sec) + int(ms or 0) / 1000.0
def _vtt_s_to_ts(x: float) -> str:
x = max(0.0, x)
h = int(x // 3600)
x -= h * 3600
m = int(x // 60)
x -= m * 60
s = int(x)
ms = int(round((x - s) * 1000))
if ms >= 1000:
s += 1
ms -= 1000
return f"{h:02d}:{m:02d}:{s:02d}.{ms:03d}"
def shift_vtt(vtt: str, offset: float) -> str:
"""Subtract `offset` seconds from every cue's start/end. WebVTT cues carry ABSOLUTE content times,
but an HLS remux session's clock is zero-based at the real keyframe (see stream.py media_start_s),
so a subtitle overlaid on that session must be shifted by that offset to line up with speech.
Processes cue BLOCKS so a cue that shifts fully into the past (end <= 0) can be DROPPED entirely.
(Collapsing them to 00:00:00.000-->00:00:00.000 made EVERY past cue count as active at currentTime 0
— where a resume/seek lands — piling all of them on screen until playback advanced past 0.) A cue
straddling 0 is clamped to start at 0."""
if not offset:
return vtt
out_blocks: list[str] = []
for block in re.split(r"\n[ \t]*\n", vtt):
if "-->" not in block:
out_blocks.append(block) # header / NOTE / STYLE — keep verbatim
continue
lines = block.split("\n")
keep = True
for i, ln in enumerate(lines):
if "-->" not in ln:
continue
left, _, right = ln.partition("-->")
rparts = right.strip().split(None, 1)
settings = (" " + rparts[1]) if len(rparts) > 1 else ""
try:
st = _vtt_ts_to_s(left.strip()) - offset
en = _vtt_ts_to_s(rparts[0]) - offset
except (ValueError, IndexError):
break # unparseable timing → leave the block as-is
if en <= 0:
keep = False # whole cue is before the session start → drop the block
else:
lines[i] = f"{_vtt_s_to_ts(st)} --> {_vtt_s_to_ts(en)}{settings}" # _vtt_s_to_ts clamps st>=0
break
if keep:
out_blocks.append("\n".join(lines))
return "\n\n".join(out_blocks)
def ffmpeg_to_vtt(src: str, sub_ord: int | None) -> str:
"""Convert one subtitle stream of a file to WebVTT via ffmpeg (for embedded subs, and non-SRT
external subs written to a temp file). `sub_ord` = ordinal among the file's subtitle streams."""
cmd = ["ffmpeg", "-nostdin", "-loglevel", "error", "-i", src,
"-map", f"0:s:{sub_ord if sub_ord is not None else 0}", "-f", "webvtt", "pipe:1"]
r = subprocess.run(cmd, capture_output=True)
if r.returncode != 0 or not r.stdout:
raise PlexError((r.stderr or b"").decode("utf-8", "replace")[:200] or "ffmpeg subtitle convert failed")
return r.stdout.decode("utf-8", "replace")
def cache_read(key: str) -> str | None:
try:
p = CACHE_DIR / f"{key}.vtt"
return p.read_text(encoding="utf-8") if p.exists() else None
except OSError:
return None
def cache_write(key: str, vtt: str) -> None:
try:
CACHE_DIR.mkdir(parents=True, exist_ok=True)
tmp = CACHE_DIR / f"{key}.vtt.tmp"
tmp.write_text(vtt, encoding="utf-8")
tmp.replace(CACHE_DIR / f"{key}.vtt") # atomic publish
except OSError:
pass