fix: handle Starlette routes in FastAPI middleware (#136)

This commit changes the FastAPI middleware so that the `"route"` info is
now optional. If it is not present, the SQL comment will not have the
controller/route info.

This info is always present in FastAPI routes. However, Starlette-based
routes (FastAPI can mount Starlette apps as sub-applications) do not and
would crash when the middleware tried to extract the information.

Fixes #133

Author: martin1keogh

python/sqlcommenter-python/google/cloud/sqlcommenter/fastapi.py

@@ -95,5 +95,5 @@ def _get_fastapi_route(fastapi_app: FastAPI, scope) -> Optional[Route]:
         # and return the route name if found.
         match, child_scope = route.matches(scope)
         if match == Match.FULL:
-            return child_scope["route"]
+            return child_scope.get("route")
     return None

python/sqlcommenter-python/tests/fastapi/app.py

@@ -5,7 +5,9 @@
 from google.cloud.sqlcommenter.fastapi import (
     SQLCommenterMiddleware, get_fastapi_info,
 )
+from starlette.applications import Starlette
 from starlette.exceptions import HTTPException as StarletteHTTPException
+from starlette.routing import Route
 
 app = FastAPI(title="SQLCommenter")
 
@@ -28,3 +30,15 @@ async def custom_http_exception_handler(request, exc):
         status_code=status.HTTP_404_NOT_FOUND,
         content=get_fastapi_info(),
     )
+
+
+def starlette_endpoint(_):
+    return JSONResponse({"from": "starlette"})
+
+
+starlette_subapi = Starlette(routes=[
+    Route("/", starlette_endpoint),
+])
+
+
+app.mount("/starlette", starlette_subapi)

python/sqlcommenter-python/tests/fastapi/tests.py

@@ -52,3 +52,13 @@ def test_get_fastapi_info_in_404_error_context(client):
 
 def test_get_fastapi_info_outside_request_context(client):
     assert get_fastapi_info() == {}
+
+
+def test_get_openapi_does_not_throw_an_error(client):
+    resp = client.get(app.docs_url)
+    assert resp.status_code == 200
+
+
+def test_get_starlette_endpoints_does_not_throw_an_error(client):
+    resp = client.get("/starlette")
+    assert resp.status_code == 200