108 lines
3.5 KiB
Python
108 lines
3.5 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-only
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# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
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import secrets
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from datetime import datetime, timedelta, timezone
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from typing import Optional
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from fastapi import Depends, HTTPException, status
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from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
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import jwt
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from .storage import load_jwt_secret, save_refresh_token, verify_refresh_token
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ALGORITHM = "HS256"
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ACCESS_TOKEN_EXPIRE_MINUTES = 60
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REFRESH_TOKEN_EXPIRE_DAYS = 7
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# Load stable secret from SQLite (set during first-time setup)
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# This will raise RuntimeError if auth hasn't been initialized yet
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try:
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SECRET_KEY = load_jwt_secret()
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except RuntimeError:
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# Fallback: use a temporary secret until setup is complete
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# This allows the app to start, but protected routes will fail until setup
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SECRET_KEY = secrets.token_urlsafe(64)
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security = HTTPBearer() # Reads Authorization: Bearer <token>
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def create_access_token(
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subject: str,
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expires_delta: Optional[timedelta] = None,
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) -> str:
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"""
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Create a signed JWT for the given subject (e.g. username).
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Tokens are valid across restarts because SECRET_KEY is stored in SQLite.
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"""
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to_encode = {"sub": subject}
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expire = datetime.now(timezone.utc) + (
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expires_delta or timedelta(minutes = ACCESS_TOKEN_EXPIRE_MINUTES)
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)
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to_encode.update({"exp": expire})
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return jwt.encode(to_encode, SECRET_KEY, algorithm = ALGORITHM)
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def create_refresh_token(subject: str) -> str:
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"""
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Create a random refresh token, store its hash in SQLite, and return it.
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Refresh tokens are opaque (not JWTs) and expire after REFRESH_TOKEN_EXPIRE_DAYS.
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"""
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token = secrets.token_urlsafe(48)
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expires_at = datetime.now(timezone.utc) + timedelta(days = REFRESH_TOKEN_EXPIRE_DAYS)
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save_refresh_token(token, subject, expires_at.isoformat())
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return token
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def refresh_access_token(refresh_token: str) -> Optional[str]:
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"""
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Validate a refresh token and issue a new access token.
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The refresh token itself is NOT consumed — it stays valid until expiry.
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Returns a new access_token or None if the refresh token is invalid/expired.
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"""
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username = verify_refresh_token(refresh_token)
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if username is None:
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return None
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return create_access_token(subject = username)
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def reload_secret() -> None:
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"""
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Reload the JWT secret from SQLite.
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Call this after setup to ensure new tokens use the persistent secret.
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"""
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global SECRET_KEY
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SECRET_KEY = load_jwt_secret()
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async def get_current_subject(
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credentials: HTTPAuthorizationCredentials = Depends(security),
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) -> str:
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"""
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FastAPI dependency to validate the JWT and return the subject.
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Use this as a dependency on routes that should be protected, e.g.:
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@router.get("/secure")
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async def secure_endpoint(current_subject: str = Depends(get_current_subject)):
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...
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"""
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token = credentials.credentials
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try:
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payload = jwt.decode(token, SECRET_KEY, algorithms = [ALGORITHM])
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subject: Optional[str] = payload.get("sub")
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if subject is None:
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raise HTTPException(
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status_code = status.HTTP_401_UNAUTHORIZED,
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detail = "Invalid token payload",
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)
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return subject
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except jwt.InvalidTokenError:
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raise HTTPException(
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status_code = status.HTTP_401_UNAUTHORIZED,
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detail = "Invalid or expired token",
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)
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