feat(auth): implement authentication endpoints and JWT handling

app/core/security.py

@@ -0,0 +1,99 @@
+from dataclasses import dataclass
+from datetime import datetime, timedelta, timezone
+from uuid import uuid4
+
+from authlib.jose import jwt  # type: ignore
+from authlib.jose.errors import JoseError  # type: ignore
+from core.config import settings
+from db.auth import get_user_by_username, is_token_revoked
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
+from models.auth import AccessTokenPayload, AuthUserDocument
+from passlib.context import CryptContext
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+bearer_scheme = HTTPBearer(auto_error=False)
+
+
+@dataclass(slots=True)
+class AuthContext:
+    token: str
+    user: AuthUserDocument
+    payload: AccessTokenPayload
+
+
+class InvalidTokenError(Exception):
+    pass
+
+
+def token_auth_error() -> HTTPException:
+    return HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+
+
+def hash_password(password: str) -> str:
+    return pwd_context.hash(password)
+
+
+def verify_password(plain_password: str, password_hash: str) -> bool:
+    return pwd_context.verify(plain_password, password_hash)
+
+
+def create_access_token(*, subject: str) -> str:
+    now = datetime.now(timezone.utc)
+    expires_delta = timedelta(minutes=settings.JWT_EXPIRE_MINUTES)
+    expires_at = int((now + expires_delta).timestamp())
+
+    header = {
+        "alg": settings.JWT_ALGORITHM,
+        "typ": "JWT",
+    }
+    payload = {
+        "sub": subject,
+        "jti": str(uuid4()),
+        "exp": expires_at,
+    }
+    token = jwt.encode(header, payload, settings.JWT_SECRET_KEY)
+    if isinstance(token, bytes):
+        return token.decode("utf-8")
+    return token
+
+
+def decode_access_token(token: str) -> AccessTokenPayload:
+    try:
+        claims = jwt.decode(token, settings.JWT_SECRET_KEY)
+        claims.validate()
+        return AccessTokenPayload.model_validate(dict(claims))
+    except (JoseError, ValueError, TypeError):
+        raise InvalidTokenError from None
+
+
+async def get_auth_context(
+    credentials: HTTPAuthorizationCredentials | None = Depends(bearer_scheme),
+) -> AuthContext:
+    if credentials is None or credentials.scheme.lower() != "bearer":
+        raise token_auth_error()
+
+    token = credentials.credentials
+    try:
+        payload = decode_access_token(token)
+    except InvalidTokenError:
+        raise token_auth_error() from None
+
+    if await is_token_revoked(payload.jti):
+        raise token_auth_error()
+
+    user = await get_user_by_username(payload.sub)
+    if user is None:
+        raise token_auth_error()
+
+    return AuthContext(token=token, user=user, payload=payload)
+
+
+async def require_authenticated_user(
+    auth_context: AuthContext = Depends(get_auth_context),
+) -> AuthUserDocument:
+    return auth_context.user