feat: bootstrap dodo phase one

backend/auth.py

@@ -0,0 +1,65 @@
+import hashlib
+import secrets
+from datetime import UTC, datetime, timedelta
+
+from argon2 import PasswordHasher
+from argon2.exceptions import InvalidHashError, VerificationError
+from fastapi import Cookie, Depends, HTTPException, Response, status
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from .config import get_settings
+from .db import get_db
+from .models import Session, User
+
+password_hasher = PasswordHasher()
+COOKIE_NAME = "dodo_session"
+
+
+def hash_token(token: str) -> str:
+    return hashlib.sha256(token.encode()).hexdigest()
+
+
+def hash_password(password: str) -> str:
+    return password_hasher.hash(password)
+
+
+def verify_password(password_hash: str, password: str) -> bool:
+    try:
+        return password_hasher.verify(password_hash, password)
+    except (InvalidHashError, VerificationError):
+        return False
+
+
+async def issue_session(db: AsyncSession, response: Response, user: User) -> None:
+    token = secrets.token_urlsafe(32)
+    expires = datetime.now(UTC) + timedelta(days=get_settings().session_days)
+    db.add(Session(token_hash=hash_token(token), user_id=user.id, expires_at=expires))
+    await db.commit()
+    response.set_cookie(
+        COOKIE_NAME, token, max_age=get_settings().session_days * 86400,
+        httponly=True, secure=get_settings().cookie_secure, samesite="lax", path="/",
+    )
+
+
+async def session_token(
+    token: str | None = Cookie(default=None, alias=COOKIE_NAME),
+) -> str:
+    if not token:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="请先登录")
+    return token
+
+
+async def current_user(
+    token: str = Depends(session_token),
+    db: AsyncSession = Depends(get_db),
+) -> User:
+    result = await db.execute(
+        select(User).join(Session).where(
+            Session.token_hash == hash_token(token), Session.expires_at > datetime.now(UTC)
+        )
+    )
+    user = result.scalar_one_or_none()
+    if user is None:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="会话已失效，请重新登录")
+    return user