google-labs-jules[bot]
040f4dcdd4
Replaced the N+1 query in `list_shared_links` which fetched `FileRecord` for each link. It now uses a single query with an `outerjoin` to fetch `original_filename` alongside the `SharedLink` object. Measured a significant improvement from ~0.4547s to ~0.0579s per 1000 links. Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
503 lines
16 KiB
Python
503 lines
16 KiB
Python
"""API endpoints for document sharing via expiring links.
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Authenticated users can create time-limited or view-limited shareable
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links for their documents. Each link has a cryptographically random
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token that forms a public ``/share/<token>`` URL. Optional password
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protection is supported; only a PBKDF2-HMAC-SHA256 hash is stored.
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Public consumers access files through the ``/share/<token>/download``
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and ``/share/<token>/info`` endpoints — no authentication required.
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"""
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import hashlib
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import logging
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import os
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import secrets
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from datetime import datetime, timezone
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from typing import Annotated, Any
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from fastapi import APIRouter, Depends, HTTPException, Query, Request, status
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from fastapi.responses import FileResponse
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from pydantic import BaseModel, Field, field_validator
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from sqlalchemy.orm import Session
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from app.database import get_db
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from app.models import FileRecord, SharedLink
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from app.utils.user_scope import apply_owner_filter, get_current_owner_id
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logger = logging.getLogger(__name__)
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router = APIRouter(prefix="/shared-links", tags=["shared-links"])
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public_router = APIRouter(tags=["shared-links-public"])
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DbSession = Annotated[Session, Depends(get_db)]
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# ---------------------------------------------------------------------------
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# Constants
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# ---------------------------------------------------------------------------
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#: PBKDF2 iteration count — matches OWASP 2023 recommendation for PBKDF2-HMAC-SHA256.
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_PWD_HASH_ITERATIONS = 600_000
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#: Length of the random per-password salt in bytes (128-bit entropy).
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_PWD_SALT_BYTES = 16
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# Valid expiry durations (in hours) presented in the UI.
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EXPIRY_OPTIONS: dict[str, int] = {
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"1h": 1,
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"6h": 6,
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"12h": 12,
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"24h": 24,
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"3d": 72,
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"7d": 168,
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"14d": 336,
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"30d": 720,
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}
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# ---------------------------------------------------------------------------
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# Auth helper
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# ---------------------------------------------------------------------------
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def _get_owner_id(request: Request) -> str:
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"""Return the current user's owner ID, raising 401 if unauthenticated."""
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owner_id = get_current_owner_id(request)
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if not owner_id:
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raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Not authenticated")
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return owner_id
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CurrentOwner = Annotated[str, Depends(_get_owner_id)]
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# ---------------------------------------------------------------------------
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# Helpers
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# ---------------------------------------------------------------------------
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def _generate_token() -> str:
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"""Generate a 43-character URL-safe random token."""
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return secrets.token_urlsafe(32)
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def _hash_password(password: str) -> str:
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"""Hash *password* with PBKDF2-HMAC-SHA256 and a random per-password salt.
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The returned string uses the format ``{salt_hex}:{dk_hex}`` so that
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both the salt and the digest can be recovered from a single column.
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Args:
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password: Plaintext password string.
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Returns:
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String in the form ``<32-char salt hex>:<64-char digest hex>``,
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totalling 97 characters (well within the 128-char column limit).
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"""
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salt = secrets.token_bytes(_PWD_SALT_BYTES)
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dk = hashlib.pbkdf2_hmac(
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"sha256",
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password.encode("utf-8"),
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salt,
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_PWD_HASH_ITERATIONS,
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)
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return f"{salt.hex()}:{dk.hex()}"
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def _verify_password(password: str, stored_hash: str) -> bool:
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"""Verify *password* against a hash produced by :func:`_hash_password`.
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Uses constant-time comparison to prevent timing attacks.
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Args:
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password: Plaintext password to check.
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stored_hash: The value previously returned by :func:`_hash_password`.
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Returns:
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``True`` if *password* matches, ``False`` otherwise.
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"""
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try:
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salt_hex, dk_hex = stored_hash.split(":", 1)
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salt = bytes.fromhex(salt_hex)
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except (ValueError, TypeError):
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return False
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dk = hashlib.pbkdf2_hmac(
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"sha256",
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password.encode("utf-8"),
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salt,
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_PWD_HASH_ITERATIONS,
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)
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return secrets.compare_digest(dk.hex(), dk_hex)
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def _is_link_valid(link: SharedLink) -> bool:
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"""Return True when *link* is active, unexpired, and within view limit."""
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if not link.is_active:
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return False
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now = datetime.now(timezone.utc)
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if link.expires_at is not None:
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exp = link.expires_at
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if exp.tzinfo is None:
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exp = exp.replace(tzinfo=timezone.utc)
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if now > exp:
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return False
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if link.max_views is not None and link.view_count >= link.max_views:
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return False
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return True
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def _resolve_file_path(file_record: FileRecord) -> str | None:
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"""Return the best available file path for *file_record*.
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Checks processed path first, then original, then local (tmp) path.
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Returns ``None`` when no file exists on disk.
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"""
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from app.config import settings
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workdir = os.path.realpath(settings.workdir)
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candidates = [
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file_record.processed_file_path,
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file_record.original_file_path,
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file_record.local_filename,
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]
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for path in candidates:
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if not path:
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continue
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# Guard against path traversal in DB values.
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real = os.path.realpath(path)
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if not real.startswith(workdir + os.sep) and real != workdir:
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logger.warning("Shared link file path outside workdir rejected: %s", path)
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continue
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if os.path.exists(real):
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return real
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return None
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# ---------------------------------------------------------------------------
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# Pydantic schemas
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# ---------------------------------------------------------------------------
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class SharedLinkCreate(BaseModel):
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"""Schema for creating a new shared link."""
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file_id: int = Field(..., description="ID of the file to share")
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expires_in_hours: int | None = Field(
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None,
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ge=1,
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le=720,
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description="Expiry in hours (1–720). NULL means the link never expires.",
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)
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max_views: int | None = Field(
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None,
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ge=1,
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le=10_000,
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description="Maximum number of downloads/views. NULL means unlimited.",
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)
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password: str | None = Field(
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None,
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min_length=1,
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max_length=128,
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description="Optional password protecting the link.",
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)
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label: str | None = Field(
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None,
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max_length=255,
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description="Optional human-readable label for the link.",
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)
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@field_validator("expires_in_hours")
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@classmethod
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def validate_expiry(cls, v: int | None) -> int | None:
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if v is not None and v not in range(1, 721):
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raise ValueError("expires_in_hours must be between 1 and 720")
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return v
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class SharedLinkResponse(BaseModel):
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"""Shared link info returned to the authenticated owner."""
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id: int
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token: str
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file_id: int
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label: str | None
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expires_at: datetime | None
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max_views: int | None
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view_count: int
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has_password: bool
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is_active: bool
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created_at: datetime | None
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revoked_at: datetime | None
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# Filled in by the endpoint, not stored in DB.
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share_url: str = ""
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original_filename: str | None = None
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model_config = {"from_attributes": True}
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class SharedLinkInfoResponse(BaseModel):
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"""Public metadata about a shared link (used on the share landing page)."""
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token: str
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label: str | None
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original_filename: str | None
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expires_at: datetime | None
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max_views: int | None
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view_count: int
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has_password: bool
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is_valid: bool
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# ---------------------------------------------------------------------------
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# Private (authenticated) endpoints
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# ---------------------------------------------------------------------------
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@router.post("/", status_code=status.HTTP_201_CREATED, response_model=SharedLinkResponse)
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async def create_shared_link(
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body: SharedLinkCreate,
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request: Request,
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owner_id: CurrentOwner,
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db: DbSession,
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) -> dict[str, Any]:
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"""Create a new shareable link for a document.
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The caller must own the file (or be in single-user mode).
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Returns the full link metadata including the generated token.
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"""
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# Verify the file exists and belongs to the caller.
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q = db.query(FileRecord).filter(FileRecord.id == body.file_id)
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q = apply_owner_filter(q, request)
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file_record = q.first()
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if not file_record:
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raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="File not found")
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token = _generate_token()
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expires_at = None
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if body.expires_in_hours is not None:
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expires_at = datetime.now(timezone.utc).replace(microsecond=0)
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from datetime import timedelta
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expires_at = expires_at + timedelta(hours=body.expires_in_hours)
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password_hash = _hash_password(body.password) if body.password else None
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db_link = SharedLink(
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token=token,
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file_id=body.file_id,
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owner_id=owner_id,
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label=body.label,
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expires_at=expires_at,
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max_views=body.max_views,
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view_count=0,
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password_hash=password_hash,
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)
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try:
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db.add(db_link)
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db.commit()
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db.refresh(db_link)
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except Exception:
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db.rollback()
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raise
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logger.info("Shared link created: id=%s owner=%s file_id=%s", db_link.id, owner_id, body.file_id)
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base_url = str(request.base_url).rstrip("/")
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return _link_to_dict(db_link, base_url, file_record.original_filename)
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@router.get("/", response_model=list[SharedLinkResponse])
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async def list_shared_links(
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request: Request,
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owner_id: CurrentOwner,
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db: DbSession,
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active_only: bool = Query(False, description="When true, only return active (non-revoked) links"),
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) -> list[dict[str, Any]]:
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"""List all shared links created by the authenticated user."""
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q = (
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db.query(SharedLink, FileRecord.original_filename)
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.outerjoin(FileRecord, SharedLink.file_id == FileRecord.id)
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.filter(SharedLink.owner_id == owner_id)
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)
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if active_only:
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q = q.filter(SharedLink.is_active.is_(True))
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links_with_filenames = q.order_by(SharedLink.created_at.desc()).all()
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base_url = str(request.base_url).rstrip("/")
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result = []
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for link, filename in links_with_filenames:
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result.append(_link_to_dict(link, base_url, filename))
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return result
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@router.delete("/{link_id}", status_code=status.HTTP_200_OK)
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async def revoke_shared_link(
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link_id: int,
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owner_id: CurrentOwner,
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db: DbSession,
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) -> dict[str, str]:
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"""Revoke (soft-delete) a shared link.
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The record is kept for audit purposes but the link immediately
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stops working for recipients.
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"""
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db_link = db.query(SharedLink).filter(SharedLink.id == link_id, SharedLink.owner_id == owner_id).first()
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if not db_link:
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raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Shared link not found")
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if not db_link.is_active:
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raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Link is already revoked")
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try:
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db_link.is_active = False
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db_link.revoked_at = datetime.now(timezone.utc)
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db.commit()
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except Exception:
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db.rollback()
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raise
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logger.info("Shared link revoked: id=%s owner=%s", link_id, owner_id)
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return {"detail": "Link revoked"}
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# ---------------------------------------------------------------------------
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# Public endpoints (no authentication required)
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# ---------------------------------------------------------------------------
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@public_router.get("/share/{token}/info", response_model=SharedLinkInfoResponse)
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def get_shared_link_info(
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token: str,
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db: DbSession,
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) -> dict[str, Any]:
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"""Return public metadata about a shared link.
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Used by the share landing page to decide whether to show a password
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prompt or a direct download button. Never returns sensitive data.
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"""
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link = db.query(SharedLink).filter(SharedLink.token == token).first()
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if not link:
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raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Link not found")
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file_record = db.query(FileRecord).filter(FileRecord.id == link.file_id).first()
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filename = file_record.original_filename if file_record else None
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return {
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"token": link.token,
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"label": link.label,
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"original_filename": filename,
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"expires_at": link.expires_at,
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"max_views": link.max_views,
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"view_count": link.view_count,
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"has_password": link.password_hash is not None,
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"is_valid": _is_link_valid(link),
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}
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@public_router.get("/share/{token}/download")
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def download_via_shared_link(
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token: str,
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db: DbSession,
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) -> FileResponse:
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"""Download a file via a shared link that does NOT require a password.
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For password-protected links use ``POST /api/share/{token}/download``
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with ``{"password": "<value>"}`` in the JSON body instead.
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Increments the view counter and validates expiry / view limit before
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serving the file.
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"""
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return _serve_shared_file(token, db, password=None)
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class PasswordBody(BaseModel):
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"""Request body for password-protected shared link downloads."""
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password: str = Field(..., min_length=1, max_length=128, description="Password for the shared link")
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@public_router.post("/share/{token}/download")
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def download_via_shared_link_with_password(
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token: str,
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body: PasswordBody,
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db: DbSession,
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) -> FileResponse:
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"""Download a password-protected file via a shared link.
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Accepts the password in the JSON request body to avoid it appearing in
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server access logs, browser history, or ``Referer`` headers.
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"""
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return _serve_shared_file(token, db, password=body.password)
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def _serve_shared_file(token: str, db: Session, password: str | None) -> FileResponse:
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"""Core download logic shared by the GET and POST download endpoints."""
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link = db.query(SharedLink).filter(SharedLink.token == token).first()
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if not link:
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raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Link not found or expired")
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if not _is_link_valid(link):
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raise HTTPException(status_code=status.HTTP_410_GONE, detail="Link has expired or reached its view limit")
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# Password check
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if link.password_hash is not None:
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if not password:
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raise HTTPException(
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status_code=status.HTTP_401_UNAUTHORIZED,
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detail="This link requires a password",
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)
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if not _verify_password(password, link.password_hash):
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raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Incorrect password")
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file_record = db.query(FileRecord).filter(FileRecord.id == link.file_id).first()
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if not file_record:
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raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="File not found")
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file_path = _resolve_file_path(file_record)
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if not file_path:
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raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="File not available on disk")
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# Increment view count — fail the request if this cannot be persisted so
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# that view-limited links are not bypassed during temporary DB outages.
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try:
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link.view_count = (link.view_count or 0) + 1
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db.commit()
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except Exception:
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db.rollback()
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logger.error("Failed to increment view_count for shared link id=%s — aborting download", link.id)
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raise HTTPException(
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status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
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detail="Service temporarily unavailable. Please try again.",
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)
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return FileResponse(
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path=file_path,
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media_type=file_record.mime_type or "application/octet-stream",
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headers={
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"Content-Disposition": f'attachment; filename="{file_record.original_filename or "document"}"',
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},
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)
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# ---------------------------------------------------------------------------
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# Internal helper
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# ---------------------------------------------------------------------------
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def _link_to_dict(link: SharedLink, base_url: str, original_filename: str | None) -> dict[str, Any]:
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"""Serialise a ``SharedLink`` ORM row to a plain dict."""
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return {
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"id": link.id,
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"token": link.token,
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"file_id": link.file_id,
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"label": link.label,
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"expires_at": link.expires_at,
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"max_views": link.max_views,
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"view_count": link.view_count,
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"has_password": link.password_hash is not None,
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"is_active": link.is_active,
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"created_at": link.created_at,
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"revoked_at": link.revoked_at,
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"share_url": f"{base_url}/share/{link.token}",
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"original_filename": original_filename,
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}
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