🐛 Bug Report — closing Durable Object websocket doesn't trigger close event

[ruifigueira]

I'm establishing a websocket connection with a durable object. In the client side (worker), if I explicitly close the websocket, no close event is triggered.

If I obtain a websocket with new WebSocket(...), for instance to connect with an external websocket, it works as expected: explicitly closing the websocket triggers the close event.

To reproduce the issue:

• create a worker project
• edit src/index.ts:

import { DurableObject } from "cloudflare:workers";

export class TestDurableObject extends DurableObject<Env> {
  constructor(state: DurableObjectState, env: Env) {
    super(state, env);
  }

  async fetch(request: Request) {
    if (request.headers.get("Upgrade") !== "websocket")
      return new Response("Expected WebSocket request", { status: 400 });

    const webSocketPair = new WebSocketPair();
    const [client, server] = Object.values(webSocketPair);

    server.accept();

    return new Response(null, {
      status: 101,
      webSocket: client,
    });
  }
}

export default {
  async fetch(request, env): Promise<Response> {
    const url = new URL(request.url);

    let ws: WebSocket;
    if (url.searchParams.has('ws')) {
      // example: http://127.0.0.1:8787/?ws=wss://echo.websocket.org/
      ws = new WebSocket(url.searchParams.get('ws')!);
    } else {
      const id = env.TEST_DO.idFromName('test-instance');
      const obj = env.TEST_DO.get(id);
      const response = await obj.fetch(request, {
        headers: {
          "Upgrade": "websocket"
        }
      });
      ws = response.webSocket!;
      ws.accept();
    }

    const logs: string[] = [];

    const { promise, resolve } = Promise.withResolvers<void>();

    ws.addEventListener('open', () => {
      logs.push('Connection opened');
      ws.close(1000);
    });
    ws.addEventListener('close', ({ code, reason }) => {
      logs.push(`Connection closed: ${JSON.stringify({ code, reason })}`);
      resolve();
    });

    await promise;

    return new Response(logs.join('\n'), { status: 200 });
  },
} satisfies ExportedHandler<Env>;

• edit wrangler.jsonc:

{
  "name": "websocket-close-test",
  "main": "src/index.ts",
  "compatibility_date": "2025-05-25",
  "compatibility_flags": [
    "nodejs_compat",
  ],
  "observability": {
    "enabled": true
  },
  "durable_objects": {
    "bindings": [
      {
        "name": "TEST_DO",
        "class_name": "TestDurableObject"
      }
    ]
  },
  "migrations": [
    {
      "tag": "v1",
      "new_sqlite_classes": ["TestDurableObject"]
    }
  ],
}

• Request http://127.0.0.1:8787
  • I will block and eventually timeout
• To check that it works properly with new WebSocket, request http://127.0.0.1:8787/?ws=wss://echo.websocket.org/
  • it will successfully output:

Connection opened
Connection closed: {"code":1000,"reason":""}