feat(FN-004): merge fusion/fn-004

apps/api/app/auth/__init__.py

@@ -0,0 +1,3 @@
+from app.auth.dependencies import get_current_active_user, get_current_user
+
+__all__ = ["get_current_user", "get_current_active_user"]

apps/api/app/auth/dependencies.py

@@ -0,0 +1,93 @@
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.auth.jwt import decode_token
+from app.config import settings
+from app.db import get_db_session
+from app.models.user import User
+
+bearer_scheme = HTTPBearer(auto_error=False)
+
+
+async def _get_or_create_dev_user(session: AsyncSession) -> User:
+    """Return or create the fixed development user."""
+    result = await session.execute(
+        select(User).where(User.authentik_sub == "dev-user")
+    )
+    user = result.scalar_one_or_none()
+    if user is None:
+        user = User(
+            authentik_sub="dev-user",
+            email="dev@localhost",
+            display_name="Dev User",
+            is_active=True,
+        )
+        session.add(user)
+        await session.commit()
+        await session.refresh(user)
+    return user
+
+
+async def get_current_user(
+    token: HTTPAuthorizationCredentials | None = Depends(bearer_scheme),
+    session: AsyncSession = Depends(get_db_session),
+) -> User:
+    if token is None:
+        if settings.debug and settings.auth_dev_bypass:
+            return await _get_or_create_dev_user(session)
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Not authenticated",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    try:
+        claims = decode_token(token.credentials)
+    except Exception as exc:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail=f"Invalid token: {exc}",
+            headers={"WWW-Authenticate": "Bearer"},
+        ) from exc
+
+    authentik_sub = claims.get("sub")
+    email = claims.get("email", "")
+    display_name = claims.get("name") or claims.get("preferred_username") or email
+
+    if not authentik_sub:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Token missing 'sub' claim",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    result = await session.execute(
+        select(User).where(User.authentik_sub == authentik_sub)
+    )
+    user = result.scalar_one_or_none()
+
+    if user is None:
+        user = User(
+            authentik_sub=authentik_sub,
+            email=email,
+            display_name=display_name,
+            is_active=True,
+        )
+        session.add(user)
+        await session.commit()
+        await session.refresh(user)
+
+    return user
+
+
+async def get_current_active_user(
+    current_user: User = Depends(get_current_user),
+) -> User:
+    if not current_user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Inactive user",
+        )
+    return current_user

apps/api/app/auth/jwt.py

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+from typing import Any
+
+import jwt
+
+from app.config import settings
+
+
+def decode_token(token: str) -> dict[str, Any]:
+    """Decode a JWT token.
+
+    When authentik_issuer_url is configured, validates the token
+    against the OIDC discovery document JWKS.
+    Otherwise, decodes without verification (local development only).
+    """
+    if settings.authentik_issuer_url:
+        import httpx
+
+        issuer = settings.authentik_issuer_url.rstrip("/")
+        discovery_url = f"{issuer}/.well-known/openid-configuration"
+        with httpx.Client() as client:
+            resp = client.get(discovery_url)
+            resp.raise_for_status()
+            discovery = resp.json()
+            jwks_uri = discovery["jwks_uri"]
+
+            jwks_resp = client.get(jwks_uri)
+            jwks_resp.raise_for_status()
+            jwks = jwks_resp.json()
+
+        signing_key = jwt.algorithms.RSAAlgorithm.from_jwk(
+            _find_matching_key(jwks, token)
+        )
+
+        return jwt.decode(
+            token,
+            signing_key,  # type: ignore[arg-type]
+            algorithms=["RS256"],
+            audience=settings.authentik_client_id,
+            issuer=settings.authentik_issuer_url,
+        )
+
+    return jwt.decode(token, options={"verify_signature": False})
+
+
+def _find_matching_key(jwks: dict[str, Any], token: str) -> dict[str, Any]:
+    """Find the key in JWKS that matches the token's kid header."""
+    unverified_header = jwt.get_unverified_header(token)
+    kid = unverified_header.get("kid")
+    for key in jwks.get("keys", []):
+        key_dict: dict[str, Any] = key
+        if key_dict.get("kid") == kid:
+            return key_dict
+    raise RuntimeError(f"No matching JWKS key found for kid={kid}")