lukasandClaude Opus 5.5
3957dd540a
Attachments are no longer stored apart from their message (they were kept twice: base64 inside the raw message and decoded on their own). The indexer records the MIME part (attachments.part_index, migration 0023); downloads, zip, inline images, thumbnails and forwarding take it out of the message; videos stream from a short-lived copy (kept a day, 1 GiB per user). A background pass on worker start removes the copies stored before, each only after checking it can be taken out again (spec App. D §D.6 item 1, criterion corrected to <= 60%). A nightly job (03:47, after the Trash/Spam purge) removes files nothing refers to any more — deleted or purged messages, previews of attachments gone, uploads no draft has used for a week, expired streaming copies. Files younger than an hour are left alone; a sent message waiting for its Sent copy is held until its job is done. Account removal keeps files a draft still uses. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
128 lines
4.1 KiB
Python
128 lines
4.1 KiB
Python
"""Attachment thumbnails for the reading pane: images and a PDF's first page.
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A thumbnail fits within THUMB_MAX × THUMB_MAX with its aspect ratio kept (the
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browser decides how to frame it), as WebP. Made once and kept beside the blob
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store — ``{BLOB_ROOT}/{user}/thumbs/{sha}-{THUMB_MAX}.webp`` — with a ``.none``
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marker for files that cannot have one (a broken image, an encrypted PDF, HEIC),
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so neither is attempted twice.
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Attachments are hostile input: decoding runs in a worker thread, oversized
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files and decompression bombs are refused.
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"""
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from __future__ import annotations
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import io
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import logging
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import uuid
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from collections.abc import Callable
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from pathlib import Path
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from app.indexer import blobstore
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logger = logging.getLogger(__name__)
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THUMB_MAX = 480 # px: sharp on a 2× screen for a tile of up to 230 px
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_MAX_INPUT_BYTES = 40 * 1024 * 1024
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_MAX_PIXELS = 64_000_000 # a larger image is refused, not decoded
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_IMAGE_MIME = frozenset(
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{"image/jpeg", "image/png", "image/gif", "image/webp", "image/bmp", "image/tiff"}
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)
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_EXT_MIME = {
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"jpg": "image/jpeg",
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"jpeg": "image/jpeg",
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"png": "image/png",
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"gif": "image/gif",
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"webp": "image/webp",
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"bmp": "image/bmp",
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"tif": "image/tiff",
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"tiff": "image/tiff",
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"pdf": "application/pdf",
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}
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def thumb_type(mime_type: str, filename: str) -> str | None:
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"""The type to render a thumbnail as, or None. Senders often label files
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application/octet-stream, so the extension stands in for a missing type."""
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mime = mime_type.lower()
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if mime in _IMAGE_MIME or mime == "application/pdf":
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return mime
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return _EXT_MIME.get(filename.rsplit(".", 1)[-1].lower()) if "." in filename else None
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def can_thumbnail(mime_type: str) -> bool:
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return mime_type in _IMAGE_MIME or mime_type == "application/pdf"
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def _path(user_id: uuid.UUID, sha: str, suffix: str) -> Path:
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return blobstore.blob_path(user_id, sha).parent.parent / "thumbs" / f"{sha}-{THUMB_MAX}{suffix}"
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def _render(data: bytes, mime_type: str) -> bytes | None:
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from PIL import Image, ImageOps
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Image.MAX_IMAGE_PIXELS = _MAX_PIXELS # beyond: DecompressionBombError
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if mime_type == "application/pdf":
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import pypdfium2 as pdfium # type: ignore[import-untyped]
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doc = pdfium.PdfDocument(data)
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try:
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page = doc[0]
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width, height = page.get_size()
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scale = THUMB_MAX / max(width, height, 1)
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img = page.render(scale=scale, draw_annots=True).to_pil()
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finally:
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doc.close()
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else:
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img = Image.open(io.BytesIO(data))
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img.seek(0) # an animation: its first frame
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img = ImageOps.exif_transpose(img) # phone photos: upright
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img.thumbnail((THUMB_MAX, THUMB_MAX))
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if img.mode not in ("RGB", "RGBA"):
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img = img.convert("RGBA" if "A" in img.getbands() or img.mode == "P" else "RGB")
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out = io.BytesIO()
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img.save(out, "WEBP", quality=80, method=4)
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return out.getvalue()
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def thumbnail(
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user_id: uuid.UUID,
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sha: str,
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mime_type: str,
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size: int,
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load: Callable[[], bytes],
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) -> bytes | None:
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"""The thumbnail of an attachment (content hash ``sha``, ``size`` bytes,
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read with ``load`` only when it is not made yet), or None if it cannot
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have one.
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Blocking (decoding is CPU work): call it in a thread.
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"""
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done = _path(user_id, sha, ".webp")
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if done.exists():
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return done.read_bytes()
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none = _path(user_id, sha, ".none")
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if none.exists() or not can_thumbnail(mime_type):
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return None
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if size > _MAX_INPUT_BYTES:
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return None
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try:
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data = load()
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except FileNotFoundError:
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return None
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try:
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thumb = _render(data, mime_type)
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except Exception as exc: # noqa: BLE001 - any undecodable file: no thumbnail
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logger.info("no thumbnail for blob %s (%s): %s", sha, mime_type, exc)
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thumb = None
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done.parent.mkdir(parents=True, exist_ok=True)
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if thumb is None:
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none.touch()
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return None
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tmp = done.with_suffix(".tmp")
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tmp.write_bytes(thumb)
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tmp.replace(done)
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return thumb
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