mirror of
https://github.com/andrewyng/openworker.git
synced 2026-09-11 06:30:25 +00:00
Rohit C Prasad
880c7859bd
Blobs live in state-dir attachments/ (sha256-named); the log carries only attachment:// refs on a normal comment event. Attach authority = comment authority; images-only allowlist with magic-byte check, 10MB cap; in-app tool + API + CLI + MCP.
109 lines
3.9 KiB
Python
109 lines
3.9 KiB
Python
"""Content-addressed attachments for board items — screenshots first.
|
|
|
|
Review artifacts don't belong in the repo (they aren't source, and they die with
|
|
checkouts) and don't belong in the board log (events carry refs, never blobs — no
|
|
megabytes under the hash chain). They live here: files named by their sha256 in the
|
|
state dir, bridged into the board as a normal comment event carrying an
|
|
`attachment://<hash>.<ext>#<name>` ref.
|
|
|
|
Content addressing buys three things: dedupe for free (the same screenshot attached
|
|
twice stores once), immutability by construction (the ref can never dangle onto
|
|
changed bytes), and location independence — on a hosted board the same ref resolves
|
|
to object storage instead of this directory.
|
|
|
|
Scope is images-only and ~10MB to start; the allowlist is the policy choke point
|
|
when that widens.
|
|
"""
|
|
|
|
from __future__ import annotations
|
|
|
|
import hashlib
|
|
import re
|
|
from pathlib import Path
|
|
from typing import Optional
|
|
|
|
from .model import BoardError
|
|
|
|
ATTACHMENT_SCHEME = "attachment://"
|
|
MAX_ATTACHMENT_BYTES = 10 * 1024 * 1024
|
|
|
|
# Extension → mime for the types we accept. Sniffed magic must agree with the
|
|
# claimed extension — a .png that isn't a PNG is refused, not renamed.
|
|
_IMAGE_TYPES = {
|
|
"png": "image/png",
|
|
"jpg": "image/jpeg",
|
|
"jpeg": "image/jpeg",
|
|
"gif": "image/gif",
|
|
"webp": "image/webp",
|
|
}
|
|
|
|
_MAGIC = {
|
|
"png": b"\x89PNG\r\n\x1a\n",
|
|
"jpg": b"\xff\xd8\xff",
|
|
"jpeg": b"\xff\xd8\xff",
|
|
"gif": b"GIF8",
|
|
"webp": b"RIFF", # RIFF….WEBP — checked with the fourcc below
|
|
}
|
|
|
|
_STORED_NAME = re.compile(r"[0-9a-f]{64}\.[a-z0-9]{1,5}")
|
|
|
|
|
|
class AttachmentStore:
|
|
def __init__(self, root: str | Path) -> None:
|
|
self.root = Path(root).expanduser()
|
|
|
|
def put(self, data: bytes, filename: str) -> str:
|
|
"""Store one attachment; returns its `attachment://` ref. Idempotent —
|
|
identical bytes land on the same file."""
|
|
ext = _validate(data, filename)
|
|
stored = f"{hashlib.sha256(data).hexdigest()}.{ext}"
|
|
self.root.mkdir(parents=True, exist_ok=True)
|
|
target = self.root / stored
|
|
if not target.exists():
|
|
tmp = target.with_suffix(target.suffix + ".tmp")
|
|
tmp.write_bytes(data)
|
|
tmp.replace(target)
|
|
safe_name = Path(filename).name.replace("#", "_")
|
|
return f"{ATTACHMENT_SCHEME}{stored}#{safe_name}"
|
|
|
|
def path_for(self, stored: str) -> Path:
|
|
"""Resolve a stored name (`<sha256>.<ext>`) to its file. The strict name
|
|
check is the traversal guard — nothing else reaches the filesystem."""
|
|
stored = stored.strip()
|
|
if not _STORED_NAME.fullmatch(stored):
|
|
raise BoardError(f"not an attachment name: {stored!r}")
|
|
path = self.root / stored
|
|
if not path.exists():
|
|
raise BoardError(f"no attachment {stored}")
|
|
return path
|
|
|
|
def mime_for(self, stored: str) -> str:
|
|
return _IMAGE_TYPES.get(stored.rsplit(".", 1)[-1], "application/octet-stream")
|
|
|
|
|
|
def stored_name(ref: str) -> Optional[str]:
|
|
"""`attachment://<hash>.<ext>#<name>` → `<hash>.<ext>`; None for other refs."""
|
|
if not ref.startswith(ATTACHMENT_SCHEME):
|
|
return None
|
|
return ref[len(ATTACHMENT_SCHEME):].split("#", 1)[0]
|
|
|
|
|
|
def _validate(data: bytes, filename: str) -> str:
|
|
if not data:
|
|
raise BoardError("attachment is empty")
|
|
if len(data) > MAX_ATTACHMENT_BYTES:
|
|
raise BoardError(
|
|
f"attachment exceeds {MAX_ATTACHMENT_BYTES // (1024 * 1024)}MB"
|
|
)
|
|
ext = Path(filename).suffix.lstrip(".").lower()
|
|
if ext not in _IMAGE_TYPES:
|
|
raise BoardError(
|
|
f"unsupported attachment type .{ext or '?'} — images only for now"
|
|
f" ({', '.join(sorted(set(_IMAGE_TYPES)))})"
|
|
)
|
|
if not data.startswith(_MAGIC[ext]) or (
|
|
ext == "webp" and data[8:12] != b"WEBP"
|
|
):
|
|
raise BoardError(f"file content does not look like .{ext}")
|
|
return "jpg" if ext == "jpeg" else ext
|