From da62ca82fea20ae8f3621425a117511843b886fc Mon Sep 17 00:00:00 2001
From: Mahmoud Salem <ma7moudalysalem@gmail.com>
Date: Tue, 7 Jul 2026 15:53:29 +0300
Subject: [PATCH] fix(api): treat client request-aborts as 499, not a logged
 500
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A cancelled HTTP request (the client disconnects, or React Query aborts an
in-flight query on unmount/refetch) makes ASP.NET's RequestAborted token fire and
the in-flight EF query throw OperationCanceledException. It was falling into the
catch-all — logged as "Unhandled exception" and answered with a 500 to a socket
that's already gone. Catch it explicitly (guarded on RequestAborted) and return
499 without the error log. Expected behaviour, not an error.
---
 .../Middleware/ExceptionHandlerMiddleware.cs        | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/server/src/ScholarPath.API/Middleware/ExceptionHandlerMiddleware.cs b/server/src/ScholarPath.API/Middleware/ExceptionHandlerMiddleware.cs
index cf32758e..f5db967b 100644
--- a/server/src/ScholarPath.API/Middleware/ExceptionHandlerMiddleware.cs
+++ b/server/src/ScholarPath.API/Middleware/ExceptionHandlerMiddleware.cs
@@ -82,6 +82,19 @@ await WriteProblemAsync(
                 "Service unavailable",
                 suex.Message).ConfigureAwait(false);
         }
+        catch (OperationCanceledException) when (context.RequestAborted.IsCancellationRequested)
+        {
+            // The client disconnected / aborted the request (e.g. React Query
+            // cancels an in-flight query on unmount or refetch), so ASP.NET's
+            // RequestAborted token fired and cancelled the EF query. This is
+            // expected, not an error — don't log it as "unhandled" or try to write
+            // a 500 to a socket that's already gone. 499 = client closed request.
+            logger.LogDebug("Request aborted by the client at {Path}", context.Request.Path);
+            if (!context.Response.HasStarted)
+            {
+                context.Response.StatusCode = 499;
+            }
+        }
         catch (Exception ex)
         {
             logger.LogError(ex, "Unhandled exception at {Path}", context.Request.Path);