第一次提交

storage.py

@@ -0,0 +1,111 @@
+import asyncio
+from datetime import UTC, datetime
+import json
+import os
+from pathlib import Path
+from tempfile import NamedTemporaryFile
+from uuid import UUID, uuid4
+
+from pydantic import ValidationError
+
+from models import Session
+
+
+class SessionNotFoundError(Exception):
+    pass
+
+
+class SessionStorageError(Exception):
+    pass
+
+
+class JsonSessionStorage:
+    def __init__(self, data_dir: Path) -> None:
+        self.data_dir = data_dir
+
+    async def create(self, system_prompt: str) -> Session:
+        return await asyncio.to_thread(self._create, system_prompt)
+
+    async def read(self, session_id: str) -> Session:
+        return await asyncio.to_thread(self._read, session_id)
+
+    async def write(self, session: Session) -> None:
+        await asyncio.to_thread(self._write, session)
+
+    def _path(self, session_id: str) -> Path:
+        try:
+            normalized = str(UUID(session_id))
+        except ValueError as exc:
+            raise SessionNotFoundError(session_id) from exc
+        return self.data_dir / f"{normalized}.json"
+
+    def _create(self, system_prompt: str) -> Session:
+        try:
+            self.data_dir.mkdir(parents=True, exist_ok=True)
+            while True:
+                now = datetime.now(UTC)
+                session = Session(
+                    session_id=str(uuid4()),
+                    system_prompt=system_prompt,
+                    created_at=now,
+                    updated_at=now,
+                )
+                path = self._path(session.session_id)
+                try:
+                    with path.open("x", encoding="utf-8") as file:
+                        json.dump(
+                            session.model_dump(mode="json"),
+                            file,
+                            ensure_ascii=False,
+                            indent=2,
+                        )
+                    return session
+                except FileExistsError:
+                    continue
+        except OSError as exc:
+            raise SessionStorageError("could not create session") from exc
+
+    def _read(self, session_id: str) -> Session:
+        path = self._path(session_id)
+        try:
+            with path.open(encoding="utf-8") as file:
+                return Session.model_validate(json.load(file))
+        except FileNotFoundError as exc:
+            raise SessionNotFoundError(session_id) from exc
+        except (OSError, json.JSONDecodeError, ValidationError) as exc:
+            raise SessionStorageError("could not read session") from exc
+
+    def _write(self, session: Session) -> None:
+        path = self._path(session.session_id)
+        if not path.exists():
+            raise SessionNotFoundError(session.session_id)
+
+        temporary_path: str | None = None
+        try:
+            self.data_dir.mkdir(parents=True, exist_ok=True)
+            with NamedTemporaryFile(
+                mode="w",
+                encoding="utf-8",
+                dir=self.data_dir,
+                prefix=f".{session.session_id}.",
+                suffix=".tmp",
+                delete=False,
+            ) as file:
+                temporary_path = file.name
+                json.dump(
+                    session.model_dump(mode="json"),
+                    file,
+                    ensure_ascii=False,
+                    indent=2,
+                )
+                file.flush()
+                os.fsync(file.fileno())
+            os.replace(temporary_path, path)
+        except OSError as exc:
+            raise SessionStorageError("could not write session") from exc
+        finally:
+            if temporary_path:
+                try:
+                    Path(temporary_path).unlink(missing_ok=True)
+                except OSError:
+                    pass