Files
member-backend/app/security/authentik_jwt.py

85 lines
2.9 KiB
Python

from __future__ import annotations
from functools import lru_cache
import jwt
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
from app.core.config import get_settings
from app.schemas.auth import AuthentikPrincipal
bearer_scheme = HTTPBearer(auto_error=False)
class AuthentikTokenVerifier:
def __init__(self, issuer: str | None, jwks_url: str | None, audience: str | None) -> None:
self.issuer = issuer.strip() if issuer else None
self.jwks_url = jwks_url.strip() if jwks_url else self._infer_jwks_url(self.issuer)
self.audience = audience.strip() if audience else None
if not self.jwks_url:
raise ValueError("AUTHENTIK_JWKS_URL or AUTHENTIK_ISSUER is required")
self._jwk_client = jwt.PyJWKClient(self.jwks_url)
@staticmethod
def _infer_jwks_url(issuer: str | None) -> str | None:
if not issuer:
return None
normalized = issuer.rstrip("/") + "/"
if normalized.endswith("/jwks/"):
return normalized
return normalized + "jwks/"
def verify_access_token(self, token: str) -> AuthentikPrincipal:
try:
signing_key = self._jwk_client.get_signing_key_from_jwt(token)
options = {
"verify_signature": True,
"verify_exp": True,
"verify_aud": bool(self.audience),
"verify_iss": bool(self.issuer),
}
claims = jwt.decode(
token,
signing_key.key,
algorithms=["RS256", "RS384", "RS512"],
audience=self.audience,
issuer=self.issuer,
options=options,
)
except Exception as exc:
raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="invalid_bearer_token") from exc
sub = claims.get("sub")
if not sub:
raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="token_missing_sub")
return AuthentikPrincipal(
sub=sub,
email=claims.get("email"),
name=claims.get("name"),
preferred_username=claims.get("preferred_username"),
)
@lru_cache
def _get_verifier() -> AuthentikTokenVerifier:
settings = get_settings()
return AuthentikTokenVerifier(
issuer=settings.authentik_issuer,
jwks_url=settings.authentik_jwks_url,
audience=settings.authentik_audience,
)
def require_authenticated_principal(
credentials: HTTPAuthorizationCredentials | None = Depends(bearer_scheme),
) -> AuthentikPrincipal:
if credentials is None or credentials.scheme.lower() != "bearer":
raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="missing_bearer_token")
verifier = _get_verifier()
return verifier.verify_access_token(credentials.credentials)