init: new structure + fix lint errors

cpv3/infrastructure/storage/local.py

@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from pathlib import Path
+from typing import BinaryIO
+
+
+@dataclass(frozen=True)
+class LocalConfig:
+    root_dir: Path
+
+
+class LocalStorageBackend:
+    def __init__(self, cfg: LocalConfig) -> None:
+        self._cfg = cfg
+        self._cfg.root_dir.mkdir(parents=True, exist_ok=True)
+
+    def _full_path(self, key: str) -> Path:
+        return (self._cfg.root_dir / key).resolve()
+
+    def upload_fileobj(
+        self, key: str, fileobj: BinaryIO, *, content_type: str | None
+    ) -> None:
+        # content_type is unused for filesystem backend.
+        _ = content_type
+
+        full_path = self._full_path(key)
+        full_path.parent.mkdir(parents=True, exist_ok=True)
+
+        with open(full_path, "wb") as out:
+            while True:
+                chunk = fileobj.read(1024 * 1024)
+                if not chunk:
+                    break
+                out.write(chunk)
+
+    def download_fileobj(self, key: str, fileobj: BinaryIO) -> None:
+        full_path = self._full_path(key)
+        with open(full_path, "rb") as src:
+            while True:
+                chunk = src.read(1024 * 1024)
+                if not chunk:
+                    break
+                fileobj.write(chunk)
+
+    def exists(self, key: str) -> bool:
+        return self._full_path(key).exists()
+
+    def size(self, key: str) -> int:
+        return self._full_path(key).stat().st_size
+
+    def delete(self, key: str) -> None:
+        path = self._full_path(key)
+        if path.exists():
+            path.unlink()
+
+    def read(self, key: str) -> bytes:
+        return self._full_path(key).read_bytes()
+
+    def generate_url(self, key: str) -> str:
+        # Served by cpv3 via /api/files/local/{path}
+        return f"/api/files/local/{key}"