v1.3 - client and admin scaffolding

backend/app/core/security.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import base64
+import hashlib
+import hmac
+import json
+import time
+from typing import Any
+
+from fastapi import HTTPException, status
+
+from app.core.config import settings
+
+
+def _encode(data: dict[str, Any]) -> str:
+    raw = json.dumps(data, separators=(",", ":"), sort_keys=True).encode("utf-8")
+    return base64.urlsafe_b64encode(raw).decode("utf-8").rstrip("=")
+
+
+def _decode(value: str) -> dict[str, Any]:
+    padding = "=" * (-len(value) % 4)
+    raw = base64.urlsafe_b64decode(f"{value}{padding}".encode("utf-8"))
+    return json.loads(raw.decode("utf-8"))
+
+
+def _sign(value: str) -> str:
+    signature = hmac.new(settings.auth_secret.encode("utf-8"), value.encode("utf-8"), hashlib.sha256).digest()
+    return base64.urlsafe_b64encode(signature).decode("utf-8").rstrip("=")
+
+
+def issue_token(payload: dict[str, Any], ttl_seconds: int = 60 * 60 * 12) -> str:
+    body = {**payload, "exp": int(time.time()) + ttl_seconds}
+    encoded = _encode(body)
+    return f"{encoded}.{_sign(encoded)}"
+
+
+def verify_token(token: str) -> dict[str, Any]:
+    try:
+        body, signature = token.split(".", 1)
+    except ValueError as exc:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid authentication token") from exc
+
+    expected_signature = _sign(body)
+    if not hmac.compare_digest(signature, expected_signature):
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid authentication token")
+
+    payload = _decode(body)
+    if int(payload.get("exp", 0)) < int(time.time()):
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Authentication token has expired")
+    return payload