feat: serve responsive WebP srcsets for faster mobile browsing

On-demand ?w= resize with a disk cache under webcache/; downloads stay full-resolution.

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -2,7 +2,8 @@
 
 # --- Host data path (Syncthing share root) ------------------------------
 # Prod default (compose.yml): /home/frank/sync.schwenk.online/data/livef12
-# Layout under that path: incoming/  variants/  intermediates/  meta/
+# Layout under that path: incoming/  variants/  intermediates/  meta/  webcache/
+# (webcache = resized WebP for srcset; safe to wipe / add to phone .stignore)
 # Local override when the absolute path does not exist:
 # DATA_HOST_DIR=./data
 # DATA_HOST_DIR=/home/frank/sync.schwenk.online/data/livef12

.gitignore

@@ -4,13 +4,6 @@
 # Runtime data (bind-mounted / Syncthing share — never in git)
 /data/
 
-# Local rembg/withoutbg comparison scratch
-/compare-bg/inputs/
-/compare-bg/outputs/
-/compare-bg/model-cache/
-/compare-bg/compare.log
-.venv-compare/
-
 # Python
 __pycache__/
 *.pyc

ARCHITECTURE.md

@@ -50,18 +50,18 @@ The gmic filter/blend chain is ported from an external reference script
 `make_random.py` (not in this repo). `config.POST_FILTERS` and asset lists
 under `assets/` mirror that script's behaviour.
 
-## Background removal choice
+## Background removal
 
-`compare-bg/` is a **standalone benchmark** (rembg models vs withoutbg).
+Production uses `u2net` + alpha matting via `app/rembg_cli.py`
-It is not part of the runtime stack. Production uses `u2net` + alpha
+(see `config.REMBG_MODEL`).
-matting via `app/rembg_cli.py` (see `config.REMBG_MODEL`).
 
 ## Known limitations (intentional)
 
 - **No web auth** — anyone with the link sees all jobs (event tool).
 - **Sequential worker** — one photo at a time; burst uploads queue.
-- **Meta JSON** — worker and web both read-modify-write `meta/*.json`
+- **Meta JSON** — worker and web share `meta/*.json` via locked
-  without file locking; concurrent remix during active processing can race.
+  read-modify-write (`fcntl.flock`); variants are merged by id so
+  concurrent remix during processing does not clobber entries.
 - **Incoming is append-only** — worker never deletes from `incoming/`.
 
 ## Dev / test

CLEANUP_PLAN.md

@@ -21,7 +21,7 @@ Phase 0 analysis (2026-07-18). Working branch: `cleanup/code-quality`.
 4. **Dead code**: `blend_layers()` unused
 5. **Duplication**: atomic JSON write ×3, `basicConfig` ×2, bool-env parsing ×2, compose env block ×2
 6. **Double meta read** on index page (`read_status` + `read_manifest`)
-7. **`compare-bg/`** — separate experiment, leave as-is (gitignored cache)
+7. ~~`compare-bg/`~~ — removed (was a standalone experiment)
 8. **`make_random.py`** — external reference only, document in ARCHITECTURE
 
 ## Risk matrix
@@ -63,6 +63,6 @@ Phase 0 analysis (2026-07-18). Working branch: `cleanup/code-quality`.
 - No `pipeline.py` module split in this pass
 - No meta file locking / concurrency fix
 - No dependency major version bumps
-- No changes to `compare-bg/` experiment
+- ~~No changes to `compare-bg/` experiment~~ (later removed entirely)
 - No deploy CI (manual `docker compose` on boka stays)
 - No behavior changes to gmic/rembg processing logic

CLEANUP_REPORT.md

@@ -31,19 +31,21 @@ behavior changes** to the photo pipeline, worker loop, or web UX.
 | Item | Reason |
 |------|--------|
 | `pipeline.py` module split | Medium risk without broader integration tests; deferred |
-| Meta file locking | Behavior change; documented in `ARCHITECTURE.md` |
 | Dependency major bumps | Per plan — list only, no auto-bump |
-| `compare-bg/` | Separate experiment; left untouched |
 | Deploy CI | Manual deploy on boka stays; STANDARDS says ask first |
-| FastAPI `TemplateResponse` API migration | Deprecation warning only; no functional change |
-| `_validate_job_id` always sanitizes to valid ID | Pre-existing; documented in tests |
 
-## Bugs noticed (not fixed)
+## Follow-ups (later branch)
 
-1. **Meta JSON race** — worker and web concurrent RMW without locking.
+Meta locking, timeout thread-local, TemplateResponse migration, stem/validate
-2. **`_filter_timeout_override` global** — thread-unsafe under concurrent remix (uvicorn workers).
+hardening, and removal of `compare-bg/` were done on a subsequent branch
-3. **`sanitize_stem("a/b")` → `"b"`** — `Path.stem` drops path prefix before slash replacement.
+(`fix/concurrency-and-cleanup`).
-4. **`_validate_job_id`** — sanitization makes rejection path effectively unreachable.
+
+## Bugs noticed (historical — fixed later)
+
+1. **Meta JSON race** — fixed with `fcntl.flock` + variant merge-by-id.
+2. **`_filter_timeout_override` global** — fixed with `threading.local`.
+3. **`sanitize_stem("a/b")` → `"b"`** — fixed (separators replaced before `Path.stem`).
+4. **`_validate_job_id`** — rejection path restored for path-like raw IDs.
 
 ## Dependency notes (suggestions only)
 
@@ -84,6 +86,5 @@ docs: update README and add ARCHITECTURE
 
 ## External references
 
-- `compare-bg/` — local venv `.venv-compare/` and 1.5GB model cache (gitignored)
 - `make_random.py` — external reference script, not vendored
 - Submodule/symlink: none

app/config.py

@@ -34,6 +34,8 @@ INTERMEDIATES_DIR = DATA_DIR / "intermediates"
 # Web bookkeeping (status + manifest). Not needed on the phone — ignore via
 # Syncthing .stignore if desired.
 META_DIR = DATA_DIR / "meta"
+# Resized WebP cache for srcset (web container only; safe to wipe / .stignore).
+WEB_CACHE_DIR = DATA_DIR / "webcache"
 ASSETS_DIR = DATA_DIR / "assets"
 PROCESSED_FILE = DATA_DIR / "processed.json"
 

app/images.py

@@ -0,0 +1,89 @@
+"""On-demand web image resizing with disk cache (srcset helpers)."""
+
+from __future__ import annotations
+
+import logging
+import tempfile
+from pathlib import Path
+from urllib.parse import quote
+
+from PIL import Image
+
+from . import config
+
+logger = logging.getLogger("livef12.images")
+
+# Allowed ?w= values for /jobs/.../files/... — keep in sync with templates.
+SRCSET_WIDTHS: tuple[int, ...] = (320, 640, 960, 1280)
+
+# Default sizes for the 1/2/4-column job + variant grids.
+GRID_SIZES = "(min-width: 960px) 25vw, (min-width: 640px) 50vw, 100vw"
+# Original/rembg pair is always two columns.
+PAIR_SIZES = "(min-width: 640px) 50vw, 50vw"
+
+
+def file_url(job_id: str, filename: str, width: int | None = None) -> str:
+    base = f"/jobs/{quote(job_id, safe='')}/files/{quote(filename, safe='')}"
+    if width is None:
+        return base
+    return f"{base}?w={width}"
+
+
+def srcset_for(job_id: str, filename: str) -> str:
+    return ", ".join(f"{file_url(job_id, filename, w)} {w}w" for w in SRCSET_WIDTHS)
+
+
+def img_attrs(job_id: str, filename: str, *, sizes: str = GRID_SIZES) -> dict[str, str]:
+    """Attrs for responsive <img>: src, srcset, sizes, full_src (lightbox)."""
+    return {
+        "src": file_url(job_id, filename, 640),
+        "srcset": srcset_for(job_id, filename),
+        "sizes": sizes,
+        # Lightbox: large webp, not the multi-MB master PNG/JPEG.
+        "full_src": file_url(job_id, filename, SRCSET_WIDTHS[-1]),
+    }
+
+
+def get_or_create_resized(source: Path, width: int) -> Path:
+    """Return a cached WebP whose longest edge is at most `width` (no upscale)."""
+    if width not in SRCSET_WIDTHS:
+        raise ValueError(f"unsupported width: {width}")
+    if not source.is_file():
+        raise FileNotFoundError(source)
+
+    config.WEB_CACHE_DIR.mkdir(parents=True, exist_ok=True)
+    cache_path = config.WEB_CACHE_DIR / f"{source.name}.w{width}.webp"
+    try:
+        if cache_path.is_file() and cache_path.stat().st_mtime >= source.stat().st_mtime:
+            return cache_path
+    except OSError:
+        pass
+
+    _write_resized(source, cache_path, width)
+    return cache_path
+
+
+def _write_resized(source: Path, dest: Path, width: int) -> None:
+    with Image.open(source) as img:
+        img.load()
+        if img.mode == "P":
+            img = img.convert("RGBA" if "transparency" in img.info else "RGB")
+        elif img.mode not in ("RGB", "RGBA"):
+            img = img.convert("RGB")
+
+        if img.width > width:
+            new_h = max(1, round(img.height * (width / img.width)))
+            img = img.resize((width, new_h), Image.Resampling.LANCZOS)
+
+        dest.parent.mkdir(parents=True, exist_ok=True)
+        with tempfile.NamedTemporaryFile(
+            dir=dest.parent, suffix=".webp", delete=False
+        ) as tmp:
+            tmp_path = Path(tmp.name)
+        try:
+            img.save(tmp_path, format="WEBP", quality=78, method=4)
+            tmp_path.replace(dest)
+        except Exception:
+            tmp_path.unlink(missing_ok=True)
+            raise
+        logger.debug("cached %s -> %s (%dx%d)", source.name, dest.name, img.width, img.height)

app/io_utils.py

@@ -2,7 +2,11 @@
 
 from __future__ import annotations
 
+import fcntl
 import json
+import os
+from collections.abc import Iterator
+from contextlib import contextmanager
 from pathlib import Path
 from typing import Any
 
@@ -23,3 +27,16 @@ def write_json_atomic(path: Path, data: Any) -> None:
     tmp = path.with_suffix(path.suffix + ".tmp")
     tmp.write_text(json.dumps(data, indent=2, ensure_ascii=False), encoding="utf-8")
     tmp.replace(path)
+
+
+@contextmanager
+def file_lock(lock_path: Path) -> Iterator[None]:
+    """Exclusive advisory lock via ``fcntl.flock`` (cross-process)."""
+    lock_path.parent.mkdir(parents=True, exist_ok=True)
+    fd = os.open(lock_path, os.O_CREAT | os.O_RDWR, 0o644)
+    try:
+        fcntl.flock(fd, fcntl.LOCK_EX)
+        yield
+    finally:
+        fcntl.flock(fd, fcntl.LOCK_UN)
+        os.close(fd)

app/main.py

@@ -13,7 +13,7 @@ from fastapi.responses import FileResponse, HTMLResponse, RedirectResponse
 from fastapi.staticfiles import StaticFiles
 from fastapi.templating import Jinja2Templates
 
-from . import config, pipeline, remix
+from . import config, images, pipeline, remix
 from .logging_config import configure_logging
 
 configure_logging()
@@ -23,6 +23,9 @@ app = FastAPI(title=config.SITE_TITLE)
 
 BASE_DIR = Path(__file__).resolve().parent
 templates = Jinja2Templates(directory=str(BASE_DIR / "templates"))
+templates.env.globals["img_attrs"] = images.img_attrs
+templates.env.globals["PAIR_SIZES"] = images.PAIR_SIZES
+templates.env.globals["GRID_SIZES"] = images.GRID_SIZES
 app.mount("/static", StaticFiles(directory=str(BASE_DIR / "static")), name="static")
 
 # Job id = sanitized source stem (may include dots).
@@ -30,7 +33,10 @@ _JOB_ID_RE = re.compile(r"^[A-Za-z0-9._-]+$")
 
 
 def _validate_job_id(job_id: str) -> str:
-    stem = pipeline.sanitize_stem(job_id)
+    raw = job_id or ""
+    if not raw.strip() or "/" in raw or "\\" in raw or ".." in raw:
+        raise HTTPException(status_code=400, detail="Ungueltige Job-ID")
+    stem = pipeline.sanitize_stem(raw)
     if not _JOB_ID_RE.match(stem):
         raise HTTPException(status_code=400, detail="Ungueltige Job-ID")
     return stem
@@ -82,8 +88,9 @@ def list_jobs() -> list[dict[str, Any]]:
 @app.get("/", response_class=HTMLResponse)
 def index(request: Request) -> HTMLResponse:
     return templates.TemplateResponse(
+        request,
         "index.html",
-        {"request": request, "jobs": list_jobs(), "site_title": config.SITE_TITLE},
+        {"jobs": list_jobs(), "site_title": config.SITE_TITLE},
     )
 
 
@@ -100,9 +107,9 @@ def job_detail(request: Request, job_id: str) -> HTMLResponse:
     )
 
     return templates.TemplateResponse(
+        request,
         "job.html",
         {
-            "request": request,
             "site_title": config.SITE_TITLE,
             "job_id": stem,
             "status": status,
@@ -116,9 +123,25 @@ def job_detail(request: Request, job_id: str) -> HTMLResponse:
 
 
 @app.get("/jobs/{job_id}/files/{filename:path}")
-def job_file(job_id: str, filename: str) -> FileResponse:
+def job_file(
+    job_id: str,
+    filename: str,
+    w: int | None = Query(None, description="Longest-edge width for srcset WebP"),
+) -> FileResponse:
     path = _safe_job_file(job_id, filename)
-    return FileResponse(path)
+    if w is None:
+        return FileResponse(path)
+    if w not in images.SRCSET_WIDTHS:
+        raise HTTPException(
+            status_code=400,
+            detail=f"Ungueltige Breite (erlaubt: {', '.join(map(str, images.SRCSET_WIDTHS))})",
+        )
+    try:
+        cached = images.get_or_create_resized(path, w)
+    except OSError as exc:
+        logger.warning("resize failed for %s w=%s: %s", path.name, w, exc)
+        raise HTTPException(status_code=500, detail="Bild konnte nicht skaliert werden") from exc
+    return FileResponse(cached, media_type="image/webp", filename=cached.name)
 
 
 @app.get("/jobs/{job_id}/remix", response_class=HTMLResponse)
@@ -166,9 +189,9 @@ def remix_form(
             }
 
     return templates.TemplateResponse(
+        request,
         "remix.html",
         {
-            "request": request,
             "site_title": config.SITE_TITLE,
             "job_id": stem,
             "options": options,

app/pipeline.py

@@ -15,6 +15,7 @@ import re
 import shutil
 import subprocess
 import sys
+import threading
 import time
 import uuid
 from collections.abc import Iterator
@@ -25,14 +26,14 @@ from pathlib import Path
 from typing import Any
 
 from . import config
-from .io_utils import read_json, write_json_atomic
+from .io_utils import file_lock, read_json, write_json_atomic
 
 logger = logging.getLogger("livef12.pipeline")
 
 _ANSI_RE = re.compile(r"\x1b\[[0-9;]*m")
 
-# Optional override for run_gmic timeout (used by the long-retry pass).
+# Per-thread override for run_gmic timeout (used by the long-retry pass).
-_filter_timeout_override: int | None = None
+_filter_timeout_state = threading.local()
 
 
 class PipelineError(RuntimeError):
@@ -69,19 +70,19 @@ def _nice(cmd: list[str]) -> list[str]:
 
 
 def _active_filter_timeout() -> int:
-    return _filter_timeout_override if _filter_timeout_override is not None else config.FILTER_TIMEOUT
+    override = getattr(_filter_timeout_state, "override", None)
+    return override if override is not None else config.FILTER_TIMEOUT
 
 
 @contextmanager
 def filter_timeout(seconds: int) -> Iterator[None]:
     """Temporarily override FILTER_TIMEOUT for run_gmic (long-retry pass)."""
-    global _filter_timeout_override
+    previous = getattr(_filter_timeout_state, "override", None)
-    previous = _filter_timeout_override
+    _filter_timeout_state.override = seconds
-    _filter_timeout_override = seconds
     try:
         yield
     finally:
-        _filter_timeout_override = previous
+        _filter_timeout_state.override = previous
 
 
 def _magick_bin() -> str:
@@ -306,8 +307,10 @@ _UNSAFE_STEM_RE = re.compile(r"[^\w.\-]+", re.UNICODE)
 
 def sanitize_stem(name: str) -> str:
     """Safe basename stem for flat files (no path separators / junk)."""
-    stem = Path(name).stem if name else ""
+    # Replace separators before Path.stem so "a/b" → "a_b", not "b".
-    stem = stem.replace("/", "_").replace("\\", "_").strip().strip(".")
+    stem = (name or "").replace("/", "_").replace("\\", "_")
+    stem = Path(stem).stem
+    stem = stem.strip().strip(".")
     stem = _UNSAFE_STEM_RE.sub("_", stem).strip("._")
     return stem or "photo"
 
@@ -354,11 +357,39 @@ def read_meta(stem: str) -> dict[str, Any] | None:
     return data if isinstance(data, dict) else None
 
 
-def _write_meta(paths: JobPaths, data: dict[str, Any]) -> None:
+def _meta_lock_path(stem: str) -> Path:
+    return config.META_DIR / f"{sanitize_stem(stem)}.lock"
+
+
+@contextmanager
+def meta_lock(stem: str) -> Iterator[None]:
+    """Exclusive lock for meta/{stem}.json read-modify-write."""
+    with file_lock(_meta_lock_path(stem)):
+        yield
+
+
+def _write_meta_unlocked(paths: JobPaths, data: dict[str, Any]) -> None:
     data["updated_at"] = now_iso()
     write_json_atomic(paths.meta, data)
 
 
+def _merge_variants(existing: list[Any], incoming: list[Any]) -> list[dict[str, Any]]:
+    """Union variants by id; incoming wins on conflict; preserve discovery order."""
+    by_id: dict[str, dict[str, Any]] = {}
+    order: list[str] = []
+    for group in (existing, incoming):
+        for item in group:
+            if not isinstance(item, dict):
+                continue
+            vid = item.get("id")
+            if not isinstance(vid, str) or not vid:
+                continue
+            if vid not in by_id:
+                order.append(vid)
+            by_id[vid] = item
+    return [by_id[vid] for vid in order]
+
+
 def read_status(job_id: str) -> dict[str, Any] | None:
     data = read_meta(job_id)
     if not data:
@@ -375,13 +406,14 @@ def read_status(job_id: str) -> dict[str, Any] | None:
 
 
 def write_status(paths: JobPaths, status: str, **extra: Any) -> None:
-    data = read_meta(paths.stem) or {}
+    with meta_lock(paths.stem):
-    data["job_id"] = paths.stem
+        data = read_meta(paths.stem) or {}
-    data["source_stem"] = paths.stem
+        data["job_id"] = paths.stem
-    data["status"] = status
+        data["source_stem"] = paths.stem
-    data.setdefault("created_at", now_iso())
+        data["status"] = status
-    data.update(extra)
+        data.setdefault("created_at", now_iso())
-    _write_meta(paths, data)
+        data.update(extra)
+        _write_meta_unlocked(paths, data)
 
 
 def read_manifest(job_id: str) -> dict[str, Any] | None:
@@ -400,16 +432,52 @@ def read_manifest(job_id: str) -> dict[str, Any] | None:
 
 
 def write_manifest(paths: JobPaths, manifest: dict[str, Any]) -> None:
-    data = read_meta(paths.stem) or {}
+    """Upsert manifest fields; merge variants by id so concurrent writers do not clobber."""
-    data["job_id"] = paths.stem
+    with meta_lock(paths.stem):
-    data["source_stem"] = manifest.get("source_stem") or paths.stem
+        data = read_meta(paths.stem) or {}
-    data["original_file"] = manifest.get("original_file")
+        data["job_id"] = paths.stem
-    data["rembg_file"] = manifest.get("rembg_file")
+        if manifest.get("source_stem"):
-    data["variants"] = manifest.get("variants") or []
+            data["source_stem"] = manifest["source_stem"]
-    if "created_at" in manifest:
+        else:
-        data.setdefault("created_at", manifest["created_at"])
+            data.setdefault("source_stem", paths.stem)
-    data.setdefault("status", data.get("status", "processing"))
+        if "original_file" in manifest and manifest["original_file"] is not None:
-    _write_meta(paths, data)
+            data["original_file"] = manifest["original_file"]
+        if "rembg_file" in manifest and manifest["rembg_file"] is not None:
+            data["rembg_file"] = manifest["rembg_file"]
+        data["variants"] = _merge_variants(data.get("variants") or [], manifest.get("variants") or [])
+        if "created_at" in manifest:
+            data.setdefault("created_at", manifest["created_at"])
+        data.setdefault("status", data.get("status", "processing"))
+        _write_meta_unlocked(paths, data)
+
+
+def append_manifest_variant(
+    paths: JobPaths,
+    entry: dict[str, Any],
+    *,
+    original_file: str | None = None,
+    rembg_file: str | None = None,
+    source_stem: str | None = None,
+    created_at: str | None = None,
+) -> None:
+    """Append one variant under meta lock (re-reads disk so concurrent updates survive)."""
+    with meta_lock(paths.stem):
+        data = read_meta(paths.stem) or {}
+        data["job_id"] = paths.stem
+        if source_stem:
+            data["source_stem"] = source_stem
+        else:
+            data.setdefault("source_stem", paths.stem)
+        if original_file:
+            data["original_file"] = original_file
+        if rembg_file:
+            data["rembg_file"] = rembg_file
+        if created_at:
+            data.setdefault("created_at", created_at)
+        data.setdefault("created_at", now_iso())
+        data.setdefault("status", data.get("status", "done"))
+        data["variants"] = _merge_variants(data.get("variants") or [], [entry])
+        _write_meta_unlocked(paths, data)
 
 
 def list_job_ids() -> list[str]:

app/remix.py

@@ -3,6 +3,7 @@ cached original + rembg output and user-chosen filters/blends/opacity."""
 
 from __future__ import annotations
 
+import uuid
 from dataclasses import dataclass
 
 from . import pipeline
@@ -52,8 +53,8 @@ def create_remix_variant(job_id: str, choice: RemixChoice) -> dict:
         "variants": [],
     }
     variant_stem = pipeline.resolve_source_stem(manifest, paths)
-    manifest.setdefault("source_stem", variant_stem)
+    # Unique id avoids collisions when two remixes run in parallel.
-    variant_id = pipeline.next_variant_id(manifest)
+    variant_id = f"v{uuid.uuid4().hex[:8]}"
 
     entry = pipeline.compose_variant(
         paths,
@@ -67,6 +68,12 @@ def create_remix_variant(job_id: str, choice: RemixChoice) -> dict:
         fg_mode=choice.fg_blend,
         opacity=choice.opacity,
     )
-    manifest["variants"].append(entry)
+    pipeline.append_manifest_variant(
-    pipeline.write_manifest(paths, manifest)
+        paths,
+        entry,
+        original_file=paths.original.name,
+        rembg_file=paths.rembg.name,
+        source_stem=variant_stem,
+        created_at=manifest.get("created_at") if isinstance(manifest.get("created_at"), str) else None,
+    )
     return entry

app/templates/base.html

@@ -44,7 +44,8 @@
       if (!target.classList.contains("lightboxable")) return;
       e.preventDefault();
       e.stopPropagation();
-      openLightbox(target.currentSrc || target.src, target.alt);
+      var full = target.getAttribute("data-full-src");
+      openLightbox(full || target.currentSrc || target.src, target.alt);
     });
 
     box.addEventListener("click", function (e) {

app/templates/index.html

@@ -9,7 +9,15 @@
         <li class="job-card">
           <a href="/jobs/{{ job.job_id }}">
             {% if job.thumbnail %}
-              <img class="thumb lightboxable" src="/jobs/{{ job.job_id }}/files/{{ job.thumbnail }}" alt="Variante von Job {{ job.job_id }}" loading="lazy">
+              {% set img = img_attrs(job.job_id, job.thumbnail) %}
+              <img class="thumb lightboxable"
+                   src="{{ img.src }}"
+                   srcset="{{ img.srcset }}"
+                   sizes="{{ img.sizes }}"
+                   data-full-src="{{ img.full_src }}"
+                   alt="Variante von Job {{ job.job_id }}"
+                   loading="lazy"
+                   decoding="async">
             {% else %}
               <span class="thumb thumb-placeholder status-{{ job.status }}">{{ job.status }}</span>
             {% endif %}

app/templates/job.html

@@ -13,8 +13,16 @@
     <h2>Original &amp; Rembg</h2>
     <div class="pair-grid">
       {% if original_name %}
+        {% set img = img_attrs(job_id, original_name, sizes=PAIR_SIZES) %}
         <figure>
-          <img class="lightboxable" src="/jobs/{{ job_id }}/files/{{ original_name }}" alt="Original" loading="lazy">
+          <img class="lightboxable"
+               src="{{ img.src }}"
+               srcset="{{ img.srcset }}"
+               sizes="{{ img.sizes }}"
+               data-full-src="{{ img.full_src }}"
+               alt="Original"
+               loading="lazy"
+               decoding="async">
           <figcaption>
             Original &middot;
             <a href="/jobs/{{ job_id }}/files/{{ original_name }}" download>Download</a>
@@ -22,8 +30,16 @@
         </figure>
       {% endif %}
       {% if has_rembg and rembg_name %}
+        {% set img = img_attrs(job_id, rembg_name, sizes=PAIR_SIZES) %}
         <figure>
-          <img class="lightboxable" src="/jobs/{{ job_id }}/files/{{ rembg_name }}" alt="Freigestellt (rembg)" loading="lazy">
+          <img class="lightboxable"
+               src="{{ img.src }}"
+               srcset="{{ img.srcset }}"
+               sizes="{{ img.sizes }}"
+               data-full-src="{{ img.full_src }}"
+               alt="Freigestellt (rembg)"
+               loading="lazy"
+               decoding="async">
           <figcaption>
             Rembg &middot;
             <a href="/jobs/{{ job_id }}/files/{{ rembg_name }}" download>Download</a>
@@ -45,8 +61,16 @@
     {% else %}
       <ul class="variant-grid">
         {% for v in manifest.variants %}
+          {% set img = img_attrs(job_id, v.file) %}
           <li class="variant-card">
-            <img class="lightboxable" src="/jobs/{{ job_id }}/files/{{ v.file }}" alt="Variante {{ v.id }}" loading="lazy">
+            <img class="lightboxable"
+                 src="{{ img.src }}"
+                 srcset="{{ img.srcset }}"
+                 sizes="{{ img.sizes }}"
+                 data-full-src="{{ img.full_src }}"
+                 alt="Variante {{ v.id }}"
+                 loading="lazy"
+                 decoding="async">
             <div class="variant-meta">
               <strong>{{ v.id }}</strong> <span class="tag">{{ v.source }}</span>
               <dl>
@@ -72,8 +96,16 @@
       <h2>Zwischenschritte</h2>
       <ul class="intermediate-grid">
         {% for name in intermediates %}
+          {% set img = img_attrs(job_id, name) %}
           <li>
-            <img class="lightboxable" src="/jobs/{{ job_id }}/files/{{ name }}" alt="{{ name }}" loading="lazy">
+            <img class="lightboxable"
+                 src="{{ img.src }}"
+                 srcset="{{ img.srcset }}"
+                 sizes="{{ img.sizes }}"
+                 data-full-src="{{ img.full_src }}"
+                 alt="{{ name }}"
+                 loading="lazy"
+                 decoding="async">
             <span>{{ name }}</span>
           </li>
         {% endfor %}

compare-bg/README.md

@@ -1,30 +0,0 @@
-# Background-removal comparison
-
-Inbox originals from `live.f12.rocks` vs. backends.
-
-## Layout
-
-- `inputs/` — originals from boka inbox
-- `outputs/` — results, naming:
-
-```
-<stem>__rembg-u2net__no-alpha.png
-<stem>__rembg-u2net__alpha.png
-<stem>__rembg-default__no-alpha.png
-<stem>__rembg-default__alpha.png
-<stem>__rembg-birefnet-general__no-alpha.png
-<stem>__rembg-birefnet-general__alpha.png
-<stem>__withoutbg-open-weights.png
-```
-
-- `rembg-default` = `rembg.remove()` without session (library default = u2net)
-- `rembg-u2net` = explicit `new_session("u2net")` — expect identical to default
-- `withoutbg` open-weights includes matting in-graph (~2GB RAM claimed)
-
-## Re-run
-
-```bash
-./run.sh
-```
-
-Skips existing non-empty outputs. Models cached in `model-cache/`.

compare-bg/run.sh

@@ -1,28 +0,0 @@
-#!/usr/bin/env bash
-# Run rembg/withoutbg comparison in Python 3.11 (host is 3.14-only).
-set -euo pipefail
-ROOT="$(cd "$(dirname "$0")" && pwd)"
-IMG="livef12-bg-compare:py311"
-LOG="$ROOT/compare.log"
-
-docker build -t "$IMG" - <<'EOF'
-FROM python:3.11-slim-bookworm
-RUN apt-get update && apt-get install -y --no-install-recommends libgl1 libglib2.0-0 \
-    && rm -rf /var/lib/apt/lists/*
-RUN pip install --no-cache-dir 'rembg>=2.0.59,<2.1' 'pillow>=10.4,<11' \
-    'onnxruntime>=1.19,<1.20' withoutbg
-WORKDIR /work
-EOF
-
-echo "Starting comparison; log: $LOG"
-docker run --rm \
-  --name livef12-bg-compare \
-  -e TQDM_DISABLE=1 \
-  -e COMPARE_INPUT=/data/inputs \
-  -e COMPARE_OUTPUT=/data/outputs \
-  -e HOME=/cache \
-  -v "$ROOT/inputs:/data/inputs:ro" \
-  -v "$ROOT/outputs:/data/outputs" \
-  -v "$ROOT/run_compare.py:/work/run_compare.py:ro" \
-  -v "$ROOT/model-cache:/cache" \
-  "$IMG" python -u /work/run_compare.py 2>&1 | tee "$LOG"

compare-bg/run_compare.py

@@ -1,115 +0,0 @@
-#!/usr/bin/env python3
-"""Compare background-removal backends on the live.f12.rocks inbox uploads.
-
-Outputs land next to each other with explicit names so Fränky can pick a winner:
-
-  <stem>__rembg-u2net__no-alpha.png
-  <stem>__rembg-u2net__alpha.png
-  <stem>__rembg-default__no-alpha.png
-  <stem>__rembg-default__alpha.png
-  <stem>__rembg-birefnet-general__no-alpha.png
-  <stem>__rembg-birefnet-general__alpha.png
-  <stem>__withoutbg-open-weights.png
-
-`rembg-default` = rembg.remove() with no session (library default model).
-`rembg-u2net`   = rembg.new_session("u2net") explicitly.
-withoutbg embeds matting in its open-weights graph — one output only.
-"""
-
-from __future__ import annotations
-
-import os
-import sys
-import time
-import traceback
-from pathlib import Path
-
-os.environ.setdefault("TQDM_DISABLE", "1")
-
-INPUT_DIR = Path(os.environ.get("COMPARE_INPUT", "/data/inputs"))
-OUTPUT_DIR = Path(os.environ.get("COMPARE_OUTPUT", "/data/outputs"))
-EXTS = {".jpg", ".jpeg", ".png", ".webp"}
-
-
-def log(msg: str) -> None:
-    print(msg, flush=True)
-
-
-def run_rembg_named(data: bytes, label: str, model: str | None, alpha: bool, out: Path) -> None:
-    from rembg import new_session, remove
-
-    t0 = time.monotonic()
-    kwargs: dict = {"alpha_matting": alpha}
-    if model is None:
-        result = remove(data, **kwargs)
-        model_note = "default"
-    else:
-        session = new_session(model)
-        result = remove(data, session=session, **kwargs)
-        model_note = model
-    out.write_bytes(result)
-    log(f"  OK  {label} model={model_note} alpha={alpha} {time.monotonic()-t0:.1f}s -> {out.name} ({out.stat().st_size} bytes)")
-
-
-def run_withoutbg(path: Path, out: Path) -> None:
-    from withoutbg import WithoutBG
-
-    t0 = time.monotonic()
-    model = WithoutBG.open_weights()
-    result = model.remove_background(str(path))
-    result.save(out)
-    log(f"  OK  withoutbg-open-weights {time.monotonic()-t0:.1f}s -> {out.name} ({out.stat().st_size} bytes)")
-
-
-def process_one(path: Path) -> None:
-    stem = path.stem
-    log(f"=== {path.name} ===")
-    data = path.read_bytes()
-    jobs = [
-        ("rembg-u2net", "u2net", False),
-        ("rembg-u2net", "u2net", True),
-        ("rembg-default", None, False),
-        ("rembg-default", None, True),
-        ("rembg-birefnet-general", "birefnet-general", False),
-        ("rembg-birefnet-general", "birefnet-general", True),
-    ]
-    for label, model, alpha in jobs:
-        tag = "alpha" if alpha else "no-alpha"
-        out = OUTPUT_DIR / f"{stem}__{label}__{tag}.png"
-        if out.exists() and out.stat().st_size > 0:
-            log(f"  SKIP {out.name} (exists)")
-            continue
-        try:
-            run_rembg_named(data, label, model, alpha, out)
-        except Exception as exc:  # noqa: BLE001
-            err = OUTPUT_DIR / f"{stem}__{label}__{tag}.ERROR.txt"
-            err.write_text(f"{type(exc).__name__}: {exc}\n\n{traceback.format_exc()}", encoding="utf-8")
-            log(f"  FAIL {label} alpha={alpha}: {type(exc).__name__}: {exc}")
-
-    out_w = OUTPUT_DIR / f"{stem}__withoutbg-open-weights.png"
-    if out_w.exists() and out_w.stat().st_size > 0:
-        log(f"  SKIP {out_w.name} (exists)")
-    else:
-        try:
-            run_withoutbg(path, out_w)
-        except Exception as exc:  # noqa: BLE001
-            err = OUTPUT_DIR / f"{stem}__withoutbg-open-weights.ERROR.txt"
-            err.write_text(f"{type(exc).__name__}: {exc}\n\n{traceback.format_exc()}", encoding="utf-8")
-            log(f"  FAIL withoutbg: {type(exc).__name__}: {exc}")
-
-
-def main() -> int:
-    OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
-    inputs = sorted(p for p in INPUT_DIR.iterdir() if p.is_file() and p.suffix.lower() in EXTS)
-    if not inputs:
-        log(f"No images in {INPUT_DIR}")
-        return 1
-    log(f"Comparing {len(inputs)} image(s); outputs -> {OUTPUT_DIR}")
-    for path in inputs:
-        process_one(path)
-    log("DONE")
-    return 0
-
-
-if __name__ == "__main__":
-    raise SystemExit(main())

tests/conftest.py

@@ -14,7 +14,8 @@ def data_dir(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> Path:
     intermediates = tmp_path / "intermediates"
     meta = tmp_path / "meta"
     inbox = tmp_path / "incoming"
-    for directory in (variants, intermediates, meta, inbox):
+    webcache = tmp_path / "webcache"
+    for directory in (variants, intermediates, meta, inbox, webcache):
         directory.mkdir()
 
     monkeypatch.setattr("app.config.DATA_DIR", tmp_path)
@@ -22,5 +23,6 @@ def data_dir(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> Path:
     monkeypatch.setattr("app.config.INTERMEDIATES_DIR", intermediates)
     monkeypatch.setattr("app.config.META_DIR", meta)
     monkeypatch.setattr("app.config.INBOX_DIR", inbox)
+    monkeypatch.setattr("app.config.WEB_CACHE_DIR", webcache)
     monkeypatch.setattr("app.config.PROCESSED_FILE", tmp_path / "processed.json")
     return tmp_path

tests/test_io_utils.py

@@ -24,3 +24,21 @@ def test_write_json_atomic_roundtrip(tmp_path: Path) -> None:
     write_json_atomic(path, payload)
     assert json.loads(path.read_text(encoding="utf-8")) == payload
     assert not path.with_suffix(path.suffix + ".tmp").exists()
+
+
+def test_file_lock_exclusive(tmp_path: Path) -> None:
+    from concurrent.futures import ThreadPoolExecutor
+
+    from app.io_utils import file_lock
+
+    lock_path = tmp_path / "job.lock"
+    counter = {"n": 0}
+
+    def bump() -> None:
+        with file_lock(lock_path):
+            current = counter["n"]
+            counter["n"] = current + 1
+
+    with ThreadPoolExecutor(max_workers=8) as pool:
+        list(pool.map(lambda _: bump(), range(40)))
+    assert counter["n"] == 40

tests/test_main.py

@@ -5,10 +5,11 @@ from __future__ import annotations
 from pathlib import Path
 
 import pytest
-from app import config, pipeline
+from app import config, images, pipeline
 from app.main import _safe_job_file, _validate_job_id, app
 from fastapi import HTTPException
 from fastapi.testclient import TestClient
+from PIL import Image
 
 
 @pytest.fixture
@@ -16,11 +17,26 @@ def client(data_dir: Path) -> TestClient:
     return TestClient(app)
 
 
+def _write_test_png(path: Path, size: tuple[int, int] = (1200, 800)) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True)
+    Image.new("RGB", size, color=(40, 80, 120)).save(path, format="PNG")
+
+
 def test_validate_job_id_sanitizes_input() -> None:
     assert _validate_job_id("foo@bar") == "foo_bar"
     assert _validate_job_id("photo01") == "photo01"
 
 
+def test_validate_job_id_rejects_path_like() -> None:
+    with pytest.raises(HTTPException) as exc:
+        _validate_job_id("a/b")
+    assert exc.value.status_code == 400
+    with pytest.raises(HTTPException):
+        _validate_job_id("../evil")
+    with pytest.raises(HTTPException):
+        _validate_job_id("")
+
+
 def test_safe_job_file_rejects_wrong_prefix(data_dir: Path) -> None:
     stem = "photo01"
     paths = pipeline.job_paths(stem)
@@ -40,3 +56,48 @@ def test_index_empty(client: TestClient) -> None:
 def test_job_not_found(client: TestClient) -> None:
     response = client.get("/jobs/does-not-exist")
     assert response.status_code == 404
+
+
+def test_job_file_srcset_resize(client: TestClient, data_dir: Path) -> None:
+    stem = "photo01"
+    paths = pipeline.job_paths(stem)
+    png = paths.variants / f"{stem}_v1.png"
+    _write_test_png(png)
+    pipeline.write_status(paths, "done", created_at="2026-01-01T00:00:00")
+    pipeline.write_manifest(
+        paths,
+        {
+            "variants": [{"id": "v1", "file": png.name}],
+            "created_at": "2026-01-01T00:00:00",
+        },
+    )
+
+    full = client.get(f"/jobs/{stem}/files/{png.name}")
+    assert full.status_code == 200
+    assert full.headers["content-type"].startswith("image/")
+
+    bad = client.get(f"/jobs/{stem}/files/{png.name}?w=999")
+    assert bad.status_code == 400
+
+    resized = client.get(f"/jobs/{stem}/files/{png.name}?w=320")
+    assert resized.status_code == 200
+    assert resized.headers["content-type"] == "image/webp"
+    assert len(resized.content) < len(full.content)
+
+    cached = config.WEB_CACHE_DIR / f"{png.name}.w320.webp"
+    assert cached.is_file()
+    with Image.open(cached) as img:
+        assert img.width == 320
+
+    index = client.get("/")
+    assert index.status_code == 200
+    assert f"/jobs/{stem}/files/{png.name}?w=640" in index.text
+    assert "srcset=" in index.text
+    assert "data-full-src=" in index.text
+
+
+def test_img_attrs_builds_srcset() -> None:
+    attrs = images.img_attrs("job1", "job1_v1.png")
+    assert attrs["src"].endswith("?w=640")
+    assert "320w" in attrs["srcset"]
+    assert attrs["full_src"].endswith("?w=1280")

tests/test_pipeline.py

@@ -13,6 +13,7 @@ from app import pipeline
     [
         ("photo.jpg", "photo"),
         ("../evil", "evil"),
+        ("a/b", "a_b"),
         ("", "photo"),
         ("  spaced  ", "spaced"),
         ("foo@bar", "foo_bar"),
@@ -78,3 +79,56 @@ def test_list_job_ids(data_dir: Path) -> None:
     paths = pipeline.job_paths("b")
     pipeline.write_status(paths, "processing")
     assert sorted(pipeline.list_job_ids()) == ["a", "b"]
+
+
+def test_parallel_manifest_merge_keeps_all_variants(data_dir: Path) -> None:
+    """Concurrent write_manifest callers must not clobber each other's variants."""
+    from concurrent.futures import ThreadPoolExecutor
+
+    paths = pipeline.job_paths("race")
+    pipeline.write_status(paths, "processing")
+    pipeline.write_manifest(
+        paths,
+        {
+            "source_stem": "race",
+            "original_file": "race_original.jpg",
+            "rembg_file": "race_rembg.png",
+            "created_at": pipeline.now_iso(),
+            "variants": [],
+        },
+    )
+
+    def write_one(i: int) -> None:
+        pipeline.write_manifest(
+            paths,
+            {
+                "variants": [{"id": f"v{i}", "file": f"race_v{i}.png"}],
+            },
+        )
+
+    with ThreadPoolExecutor(max_workers=8) as pool:
+        list(pool.map(write_one, range(20)))
+
+    meta = pipeline.read_meta("race")
+    assert meta is not None
+    ids = {v["id"] for v in meta["variants"]}
+    assert ids == {f"v{i}" for i in range(20)}
+    assert meta["original_file"] == "race_original.jpg"
+
+
+def test_filter_timeout_is_thread_local() -> None:
+    import threading
+
+    results: dict[str, int] = {}
+
+    def worker(name: str, value: int) -> None:
+        with pipeline.filter_timeout(value):
+            results[name] = pipeline._active_filter_timeout()
+
+    t1 = threading.Thread(target=worker, args=("a", 11))
+    t2 = threading.Thread(target=worker, args=("b", 22))
+    t1.start()
+    t2.start()
+    t1.join()
+    t2.join()
+    assert results == {"a": 11, "b": 22}