bot-backend
14f3ef2019
Co-authored-by: bot-backend <bot-backend@gendsgn.local> Co-committed-by: bot-backend <bot-backend@gendsgn.local>
67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
"""Thumbnail generation for DOM.РФ photos.
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Strategy: original PNG/JPG ~1-3 MB downloaded by scraper to
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data/raw/domrf_photos/<obj_id>/<file_id>.{png,jpg}. We additionally write a
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WebP cover-thumbnail at 320×240 (~10-30 KB) next to it, suffix `_thumb.webp`.
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The frontend grid uses /api/v1/photos/<obj_id>/<file_id>?size=thumb. Lightbox
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opens the original DOM.РФ URL (we don't need to mirror originals).
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"""
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from __future__ import annotations
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import logging
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import os
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from pathlib import Path
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from PIL import Image, ImageOps
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logger = logging.getLogger(__name__)
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THUMB_SIZE: tuple[int, int] = (320, 240)
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THUMB_QUALITY: int = 70
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THUMB_SUFFIX: str = "_thumb.webp"
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def thumb_path_for(src: Path) -> Path:
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"""Return canonical thumbnail path next to the source file."""
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return src.with_name(src.stem + THUMB_SUFFIX)
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def make_thumbnail(
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src: Path,
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*,
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size: tuple[int, int] = THUMB_SIZE,
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quality: int = THUMB_QUALITY,
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overwrite: bool = False,
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) -> Path | None:
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"""Generate a WebP cover-thumbnail next to src. Returns thumb path on success.
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Skips if thumb already exists and overwrite=False. Returns None on any error
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(logged) so callers can keep going with the next file.
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"""
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if not src.exists():
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return None
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dst = thumb_path_for(src)
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if dst.exists() and not overwrite:
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return dst
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try:
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with Image.open(src) as im:
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im = ImageOps.exif_transpose(im)
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im = im.convert("RGB")
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im = ImageOps.fit(im, size, method=Image.Resampling.LANCZOS)
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dst.parent.mkdir(parents=True, exist_ok=True)
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# Atomic write: encode to a sibling temp file, then os.replace() so a
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# crash/OOM mid-encode never leaves a truncated .webp at the canonical
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# path (which dst.exists() would later treat as a valid cached thumb).
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tmp = dst.with_name(f".{dst.name}.tmp")
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try:
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im.save(tmp, format="WEBP", quality=quality, method=4)
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os.replace(tmp, dst)
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except BaseException:
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tmp.unlink(missing_ok=True)
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raise
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return dst
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except Exception as e:
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logger.warning("thumbnail %s failed: %s", src, e)
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return None
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