---
title: Handle incoming request cancellation in Workers with Request.signal
description: Workers can now add event listeners on Request.signal and perform tasks when the request is cancelled by the client
image: https://developers.cloudflare.com/changelog-preview.png
---

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## Handle incoming request cancellation in Workers with Request.signal

May 22, 2025 

[ Workers ](https://developers.cloudflare.com/workers/) 

In Cloudflare Workers, you can now attach an event listener to [Request](https://developers.cloudflare.com/workers/runtime-apis/request/) objects, using the [signal property ↗](https://developer.mozilla.org/en-US/docs/Web/API/Request/signal). This allows you to perform tasks when the request to your Worker is canceled by the client. To use this feature, you must set the [enable\_request\_signal](https://developers.cloudflare.com/workers/configuration/compatibility-flags/#enable-requestsignal-for-incoming-requests) compatibility flag.

You can use a listener to perform cleanup tasks or write to logs before your Worker's invocation ends. For example, if you run the Worker below, and then abort the request from the client, a log will be written:

* [  JavaScript ](#tab-panel-2749)
* [  TypeScript ](#tab-panel-2750)

index.js

```
export default {  async fetch(request, env, ctx) {    // This sets up an event listener that will be called if the client disconnects from your    // worker.    request.signal.addEventListener("abort", () => {      console.log("The request was aborted!");    });
    const { readable, writable } = new IdentityTransformStream();    sendPing(writable);    return new Response(readable, {      headers: { "Content-Type": "text/plain" },    });  },};
async function sendPing(writable) {  const writer = writable.getWriter();  const enc = new TextEncoder();
  for (;;) {    // Send 'ping' every second to keep the connection alive    await writer.write(enc.encode("ping\r\n"));    await scheduler.wait(1000);  }}
```

index.ts

```
export default {  async fetch(request, env, ctx): Promise<Response> {    // This sets up an event listener that will be called if the client disconnects from your    // worker.    request.signal.addEventListener('abort', () => {      console.log('The request was aborted!');    });
    const { readable, writable } = new IdentityTransformStream();    sendPing(writable);    return new Response(readable, { headers: { 'Content-Type': 'text/plain' } });  },} satisfies ExportedHandler<Env>;
async function sendPing(writable: WritableStream): Promise<void> {  const writer = writable.getWriter();  const enc = new TextEncoder();
  for (;;) {    // Send 'ping' every second to keep the connection alive    await writer.write(enc.encode('ping\r\n'));    await scheduler.wait(1000);  }}
```

For more information see the [Request documentation](https://developers.cloudflare.com/workers/runtime-apis/request).

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```