Use Depends injection to extract user name

src/blueapi/service/main.py

@@ -18,6 +18,7 @@
 )
 from fastapi.datastructures import Address
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.requests import HTTPConnection
 from fastapi.responses import RedirectResponse, StreamingResponse
 from fastapi.security import OAuth2AuthorizationCodeBearer
 from observability_utils.tracing import (
@@ -161,6 +162,11 @@ def inner(request: Request, access_token: str = Depends(oauth_scheme)):
     return inner
 
 
+def _user(request: HTTPConnection) -> str | None:
+    user = getattr(request.state, "decoded_access_token", {})
+    return user.get("fedid", None)
+
+
 TRACER = get_tracer("interface")
 
 
@@ -283,18 +289,11 @@ def submit_task(
     response: Response,
     task_request: Annotated[TaskRequest, Body(..., examples=[example_task_request])],
     runner: Annotated[WorkerDispatcher, Depends(_runner)],
+    user: Annotated[str, Depends(_user)],
 ) -> TaskResponse:
     """Submit a task to the worker."""
     try:
-        # Extract user from jwt if using OIDC (if jwt exists)
-        access_token: dict[str, Any] | None = getattr(
-            request.state, "decoded_access_token", None
-        )
-        if access_token:
-            user: str = access_token.get("fedid", "Unknown")
-        else:
-            user = "Unknown"
-
+        user = user or "UNKNOWN"
         task_id: str = runner.run(interface.submit_task, task_request, {"user": user})
         response.headers["Location"] = f"{request.url}/{task_id}"
         return TaskResponse(task_id=task_id)