fix: handle SSE controller errors gracefully

- Add isActive checks before writing to SSE controller
- Wrap controller operations in try/catch to prevent 'already closed' errors
- Fix race condition when client disconnects during SSE streaming

apps/backoffice/app/api/jobs/[id]/stream/route.ts

@@ -33,27 +33,39 @@ export async function GET(
             },
           });
           
-          if (response.ok) {
+          if (response.ok && isActive) {
             const data = await response.json();
             const dataStr = JSON.stringify(data);
             
             // Only send if data changed
-            if (dataStr !== lastData) {
+            if (dataStr !== lastData && isActive) {
               lastData = dataStr;
+              try {
                 controller.enqueue(
                   new TextEncoder().encode(`data: ${dataStr}\n\n`)
                 );
+              } catch (err) {
+                // Controller closed, ignore
+                isActive = false;
+                return;
+              }
               
               // Stop polling if job is complete
               if (data.status === "success" || data.status === "failed" || data.status === "cancelled") {
                 isActive = false;
+                try {
                   controller.close();
+                } catch (err) {
+                  // Already closed, ignore
+                }
               }
             }
           }
         } catch (error) {
+          if (isActive) {
             console.error("SSE fetch error:", error);
           }
+        }
       };
       
       // Initial fetch

apps/backoffice/app/api/jobs/stream/route.ts

@@ -28,21 +28,28 @@ export async function GET(request: NextRequest) {
             },
           });
           
-          if (response.ok) {
+          if (response.ok && isActive) {
             const data = await response.json();
             const dataStr = JSON.stringify(data);
             
             // Send if data changed
-            if (dataStr !== lastData) {
+            if (dataStr !== lastData && isActive) {
               lastData = dataStr;
+              try {
                 controller.enqueue(
                   new TextEncoder().encode(`data: ${dataStr}\n\n`)
                 );
+              } catch (err) {
+                // Controller closed, ignore
+                isActive = false;
+              }
             }
           }
         } catch (error) {
+          if (isActive) {
             console.error("SSE fetch error:", error);
           }
+        }
       };
       
       // Initial fetch