Initial commit

backend/app/services/storage.py

@@ -0,0 +1,59 @@
+"""File storage utilities for persistence, retrieval, and checksum calculation."""
+
+import hashlib
+import uuid
+from datetime import UTC, datetime
+from pathlib import Path
+
+from app.core.config import get_settings
+
+
+settings = get_settings()
+
+
+def ensure_storage() -> None:
+    """Ensures required storage directories exist at service startup."""
+
+    for relative in ["originals", "derived/previews", "tmp"]:
+        (settings.storage_root / relative).mkdir(parents=True, exist_ok=True)
+
+
+def compute_sha256(data: bytes) -> str:
+    """Computes a SHA-256 hex digest for raw file bytes."""
+
+    return hashlib.sha256(data).hexdigest()
+
+
+def store_bytes(filename: str, data: bytes) -> str:
+    """Stores file content under a unique path and returns its storage-relative location."""
+
+    stamp = datetime.now(UTC).strftime("%Y/%m/%d")
+    safe_ext = Path(filename).suffix.lower()
+    target_dir = settings.storage_root / "originals" / stamp
+    target_dir.mkdir(parents=True, exist_ok=True)
+    target_name = f"{uuid.uuid4()}{safe_ext}"
+    target_path = target_dir / target_name
+    target_path.write_bytes(data)
+    return str(target_path.relative_to(settings.storage_root))
+
+
+def read_bytes(relative_path: str) -> bytes:
+    """Reads and returns bytes from a storage-relative path."""
+
+    return (settings.storage_root / relative_path).read_bytes()
+
+
+def absolute_path(relative_path: str) -> Path:
+    """Returns the absolute filesystem path for a storage-relative location."""
+
+    return settings.storage_root / relative_path
+
+
+def write_preview(document_id: str, data: bytes, suffix: str = ".jpg") -> str:
+    """Writes preview bytes and returns the preview path relative to storage root."""
+
+    target_dir = settings.storage_root / "derived" / "previews"
+    target_dir.mkdir(parents=True, exist_ok=True)
+    target_path = target_dir / f"{document_id}{suffix}"
+    target_path.write_bytes(data)
+    return str(target_path.relative_to(settings.storage_root))