Merge PR #6: HA-Client-Fehler sicher mappen

app/core/__init__.py

@@ -0,0 +1 @@
+"""Core application helpers."""

app/core/exception_handlers.py

@@ -0,0 +1,23 @@
+from __future__ import annotations
+
+from fastapi import FastAPI, Request, status
+from fastapi.responses import JSONResponse
+
+from app.ha.exceptions import HaAuthError, HaClientError, HaHttpError, HaTimeoutError
+
+
+def register_exception_handlers(app: FastAPI) -> None:
+    @app.exception_handler(HaClientError)
+    async def handle_ha_client_error(_: Request, exc: HaClientError) -> JSONResponse:
+        return JSONResponse(
+            status_code=_status_code_for_ha_error(exc),
+            content={"detail": exc.public_detail},
+        )
+
+
+def _status_code_for_ha_error(exc: HaClientError) -> int:
+    if isinstance(exc, HaTimeoutError):
+        return status.HTTP_504_GATEWAY_TIMEOUT
+    if isinstance(exc, (HaAuthError, HaHttpError)):
+        return status.HTTP_502_BAD_GATEWAY
+    return status.HTTP_502_BAD_GATEWAY

app/ha/client.py

@@ -6,6 +6,13 @@ from typing import Any
 
 import requests
 
+from app.ha.exceptions import (
+    HaAuthError,
+    HaHttpError,
+    HaTimeoutError,
+    HaUnexpectedPayloadError,
+)
+
 logger = logging.getLogger(__name__)
 
 
@@ -26,13 +33,35 @@ class HaClient:
         })
 
     def list_entities(self) -> list[dict[str, Any]]:
+        try:
             response = self._session.get(
                 f"{self._settings.url}/api/states",
                 timeout=self._settings.timeout_seconds,
             )
+        except requests.Timeout as exc:
+            raise HaTimeoutError("Home Assistant request timed out.") from exc
+        except requests.RequestException as exc:
+            raise HaHttpError(status_code=502, message="Home Assistant request failed.") from exc
+
+        if response.status_code in {401, 403}:
+            raise HaAuthError(
+                status_code=response.status_code,
+                message="Home Assistant authentication failed.",
+            )
+
+        try:
             response.raise_for_status()
+        except requests.HTTPError as exc:
+            raise HaHttpError(
+                status_code=response.status_code,
+                message="Home Assistant returned an HTTP error.",
+            ) from exc
+
+        try:
             payload = response.json()
+        except ValueError as exc:
+            raise HaUnexpectedPayloadError("Home Assistant returned invalid JSON.") from exc
+
         if not isinstance(payload, list):
-            msg = "Home Assistant states response must be a list."
-            raise TypeError(msg)
+            raise HaUnexpectedPayloadError("Home Assistant states response must be a list.")
         return payload

app/ha/exceptions.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+
+class HaClientError(Exception):
+    """Base class for Home Assistant integration failures."""
+
+    public_detail = "Home Assistant is currently unavailable."
+
+
+class HaTimeoutError(HaClientError):
+    public_detail = "Home Assistant request timed out."
+
+
+class HaHttpError(HaClientError):
+    public_detail = "Home Assistant returned an error."
+
+    def __init__(self, status_code: int, message: str | None = None) -> None:
+        super().__init__(message or self.public_detail)
+        self.status_code = status_code
+
+
+class HaAuthError(HaHttpError):
+    public_detail = "Home Assistant authentication failed."
+
+
+class HaUnexpectedPayloadError(HaClientError):
+    public_detail = "Home Assistant returned an unexpected response."

app/main.py

@@ -5,6 +5,7 @@ from fastapi import FastAPI
 
 from app.api.v1.entities import router as entities_router
 from app.config import load_settings
+from app.core.exception_handlers import register_exception_handlers
 from app.ha.client import HaClient, HaClientSettings
 from app.ha.reader import HaReader
 
@@ -31,6 +32,7 @@ app = FastAPI(
     lifespan=lifespan,
 )
 
+register_exception_handlers(app)
 
 app.include_router(entities_router)
 

tests/api/test_entities.py

@@ -2,6 +2,7 @@ from collections.abc import Sequence
 
 from fastapi.testclient import TestClient
 
+from app.ha.exceptions import HaTimeoutError
 from app.ha.models import HaEntitySummary
 from app.ha.reader import HaReader
 from app.main import app
@@ -15,6 +16,14 @@ class FakeHaReader(HaReader):
         return [HaEntitySummary(entity_id="sensor.temperature", domain="sensor")]
 
 
+class TimeoutHaReader(HaReader):
+    def __init__(self) -> None:
+        pass
+
+    def read_entities(self) -> Sequence[HaEntitySummary]:
+        raise HaTimeoutError("contains internal details that must not leak")
+
+
 def test_openapi_docs_are_available() -> None:
     with TestClient(app) as client:
         response = client.get("/docs")
@@ -44,3 +53,11 @@ def test_entities_returns_503_without_home_assistant_config() -> None:
             delattr(app.state, "ha_reader")
         response = client.get("/v1/entities")
     assert response.status_code == 503
+
+
+def test_entities_maps_ha_errors_without_leaking_details() -> None:
+    with TestClient(app) as client:
+        app.state.ha_reader = TimeoutHaReader()
+        response = client.get("/v1/entities")
+    assert response.status_code == 504
+    assert response.json() == {"detail": "Home Assistant request timed out."}

tests/ha/test_ha_client.py

@@ -0,0 +1,79 @@
+from __future__ import annotations
+
+from unittest.mock import Mock
+
+import pytest
+import requests
+
+from app.ha.client import HaClient, HaClientSettings
+from app.ha.exceptions import (
+    HaAuthError,
+    HaHttpError,
+    HaTimeoutError,
+    HaUnexpectedPayloadError,
+)
+
+
+def _client_with_response(response: Mock) -> HaClient:
+    client = HaClient(HaClientSettings(url="http://ha.local", token="secret-token"))
+    client._session.get = Mock(return_value=response)  # type: ignore[method-assign]
+    return client
+
+
+def _response(status_code: int = 200, payload: object | None = None) -> Mock:
+    response = Mock()
+    response.status_code = status_code
+    response.json.return_value = [] if payload is None else payload
+    if status_code >= 400:
+        response.raise_for_status.side_effect = requests.HTTPError("upstream failed")
+    return response
+
+
+def test_list_entities_returns_home_assistant_payload() -> None:
+    payload = [{"entity_id": "sensor.temperature", "state": "21"}]
+    client = _client_with_response(_response(payload=payload))
+
+    assert client.list_entities() == payload
+
+
+def test_list_entities_maps_timeout() -> None:
+    client = HaClient(HaClientSettings(url="http://ha.local", token="secret-token"))
+    client._session.get = Mock(side_effect=requests.Timeout("secret-token"))  # type: ignore[method-assign]
+
+    with pytest.raises(HaTimeoutError):
+        client.list_entities()
+
+
+@pytest.mark.parametrize("status_code", [401, 403])
+def test_list_entities_maps_auth_errors(status_code: int) -> None:
+    client = _client_with_response(_response(status_code=status_code))
+
+    with pytest.raises(HaAuthError) as exc_info:
+        client.list_entities()
+
+    assert exc_info.value.status_code == status_code
+
+
+def test_list_entities_maps_http_errors() -> None:
+    client = _client_with_response(_response(status_code=500))
+
+    with pytest.raises(HaHttpError) as exc_info:
+        client.list_entities()
+
+    assert exc_info.value.status_code == 500
+
+
+def test_list_entities_rejects_invalid_json() -> None:
+    response = _response()
+    response.json.side_effect = ValueError("not json")
+    client = _client_with_response(response)
+
+    with pytest.raises(HaUnexpectedPayloadError):
+        client.list_entities()
+
+
+def test_list_entities_rejects_non_list_payload() -> None:
+    client = _client_with_response(_response(payload={"entity_id": "sensor.temperature"}))
+
+    with pytest.raises(HaUnexpectedPayloadError):
+        client.list_entities()