Request.signal abort event not called for SSE

[mihaiandrei97]

Which project does this relate to?

Start

Describe the bug

While trying to implement SSE, it seems the abort event is not triggered on request.signal when the connection is closed.

import { createAPIFileRoute } from '@tanstack/react-start/api'

export const APIRoute = createAPIFileRoute('/api/login/test')({
  GET: ({ request, params }) => {
    const responseHeaders = {
        "Content-Type": "text/event-stream",
        "Cache-Control": "no-cache",
        Connection: "keep-alive",
      };
    
      const stream = new ReadableStream({
        start(controller) {
          const encoder = new TextEncoder();
    
          // Function to send messages to this client
          const send = (message: string) => {
            controller.enqueue(encoder.encode(`data: ${message}\n\n`));
          };

          request.signal.addEventListener("abort", () => {
            console.log("Client disconnected ");
            controller.close();
          });
    
    
          // Send an initial message
          setInterval(() => {
            send("Ping");
          }, 1000);
    
        },
         cancel() {
          // Cleanup logic if needed
          console.log("Client disconnected")
        },
      });
    
      return new Response(stream, { headers: responseHeaders });
  },
})

Your Example Website or App

https://stackblitz.com/edit/tanstack-router-xajqhjwq?file=app%2Froutes%2Fapi%2Fsse.ts&preset=node

Steps to Reproduce the Bug or Issue

1. Go to: https://stackblitz.com/edit/tanstack-router-xajqhjwq?file=app%2Froutes%2Fapi%2Fsse.ts&preset=node
2. Navigate to /api/sse
3. You will see Sending message to client in the console and also the ping message on the screen.
4. Refresh the page or navigate to /
5. You should see Client disconnected but neither method is called.

Expected behavior

Abort event or cancel should be called when the request is canceled.

request.signal.addEventListener('abort', () => {
    console.log('Client disconnected ');
    controller.close();
  });

cancel() {
        // Cleanup logic if needed
        console.log('Client disconnected');
      },

Screenshots or Videos

No response

Platform

• OS: [e.g. macOS, Windows, Linux]
• Browser: [e.g. Chrome, Safari, Firefox]
• Version: [e.g. 91.1]

Additional context

No response

[schiller-manuel]

duplicate of #3490