---
title: Use ReadableStream with Durable Object and Workers
description: Stream ReadableStream from Durable Objects.
image: https://edgetunnel-b2h.pages.dev/dev-products-preview.png
---

> Documentation Index  
> Fetch the complete documentation index at: https://edgetunnel-b2h.pages.dev/durable-objects/llms.txt  
> Use this file to discover all available pages before exploring further. 

[Skip to content](#%5Ftop) 

# Use ReadableStream with Durable Object and Workers

Stream ReadableStream from Durable Objects.

This example demonstrates:

* A Worker receives a request, and forwards it to a Durable Object `my-id`.
* The Durable Object streams an incrementing number every second, until it receives `AbortSignal`.
* The Worker reads and logs the values from the stream.
* The Worker then cancels the stream after 5 values.

* [  JavaScript ](#tab-panel-9033)
* [  TypeScript ](#tab-panel-9034)

**JavaScript**

```js
import { DurableObject } from "cloudflare:workers";


// Send incremented counter value every second
async function* dataSource(signal) {
  let counter = 0;
  while (!signal.aborted) {
    yield counter++;
    await new Promise((resolve) => setTimeout(resolve, 1_000));
  }


  console.log("Data source cancelled");
}


export class MyDurableObject extends DurableObject {
  async fetch(request) {
    const abortController = new AbortController();


    const stream = new ReadableStream({
      async start(controller) {
        if (request.signal.aborted) {
          controller.close();
          abortController.abort();
          return;
        }


        for await (const value of dataSource(abortController.signal)) {
          controller.enqueue(new TextEncoder().encode(String(value)));
        }
      },
      cancel() {
        console.log("Stream cancelled");
        abortController.abort();
      },
    });


    const headers = new Headers({
      "Content-Type": "application/octet-stream",
    });


    return new Response(stream, { headers });
  }
}


export default {
  async fetch(request, env, ctx) {
    const stub = env.MY_DURABLE_OBJECT.getByName("foo");
    const response = await stub.fetch(request, { ...request });
    if (!response.ok || !response.body) {
      return new Response("Invalid response", { status: 500 });
    }


    const reader = response.body
      .pipeThrough(new TextDecoderStream())
      .getReader();


    let data = [];
    let i = 0;
    while (true) {
      // Cancel the stream after 5 messages
      if (i > 5) {
        reader.cancel();
        break;
      }
      const { value, done } = await reader.read();


      if (value) {
        console.log(`Got value ${value}`);
        data = [...data, value];
      }


      if (done) {
        break;
      }
      i++;
    }


    return Response.json(data);
  },
};
```

**TypeScript**

```ts
import { DurableObject } from 'cloudflare:workers';


// Send incremented counter value every second
async function* dataSource(signal: AbortSignal) {
    let counter = 0;
    while (!signal.aborted) {
        yield counter++;
        await new Promise((resolve) => setTimeout(resolve, 1_000));
    }


    console.log('Data source cancelled');
}


export class MyDurableObject extends DurableObject<Env> {
    async fetch(request: Request): Promise<Response> {
        const abortController = new AbortController();


        const stream = new ReadableStream({
            async start(controller) {
                if (request.signal.aborted) {
                    controller.close();
                    abortController.abort();
                    return;
                }


                for await (const value of dataSource(abortController.signal)) {
                    controller.enqueue(new TextEncoder().encode(String(value)));
                }
            },
            cancel() {
                console.log('Stream cancelled');
                abortController.abort();
            },
        });


        const headers = new Headers({
            'Content-Type': 'application/octet-stream',
        });


        return new Response(stream, { headers });
    }


}


export default {
    async fetch(request, env, ctx): Promise<Response> {
        const stub = env.MY_DURABLE_OBJECT.getByName("foo");
        const response = await stub.fetch(request, { ...request });
        if (!response.ok || !response.body) {
            return new Response('Invalid response', { status: 500 });
        }


        const reader = response.body.pipeThrough(new TextDecoderStream()).getReader();


        let data = [] as string[];
        let i = 0;
        while (true) {
            // Cancel the stream after 5 messages
            if (i > 5) {
                reader.cancel();
                break;
            }
            const { value, done } = await reader.read();


            if (value) {
                console.log(`Got value ${value}`);
                data = [...data, value];
            }


            if (done) {
                break;
            }
            i++;
        }


        return Response.json(data);
    },


} satisfies ExportedHandler<Env>;
```

Note

In a setup where a Durable Object returns a readable stream to a Worker, if the Worker cancels the Durable Object's readable stream, the cancellation propagates to the Durable Object.

```json
{"@context":"https://schema.org","@type":"TechArticle","@id":"https://edgetunnel-b2h.pages.dev/durable-objects/examples/readable-stream/#page","headline":"Use ReadableStream with Durable Object and Workers · Cloudflare Durable Objects docs","description":"Stream ReadableStream from Durable Objects.","url":"https://edgetunnel-b2h.pages.dev/durable-objects/examples/readable-stream/","inLanguage":"en","image":"https://edgetunnel-b2h.pages.dev/dev-products-preview.png","dateModified":"2026-04-21","publisher":{"@type":"Organization","name":"Cloudflare","url":"https://www.cloudflare.com/"},"isPartOf":{"@type":"WebSite","@id":"https://edgetunnel-b2h.pages.dev/#website","name":"Cloudflare Docs","url":"https://edgetunnel-b2h.pages.dev/"}}
{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/durable-objects/","name":"Durable Objects"}},{"@type":"ListItem","position":3,"item":{"@id":"/durable-objects/examples/","name":"Examples"}},{"@type":"ListItem","position":4,"item":{"@id":"/durable-objects/examples/readable-stream/","name":"Use ReadableStream with Durable Object and Workers"}}]}
```