Websocket subprotocol results in Error: The script will never generate a response

playsonmac · 2025-02-02T13:22:27.331Z

Websockets - sending subprotocols (auth token smuggling) results in Error: The script will never generate a response. Client: ``` const ws = new WebSocket(wsUrl, "potato"); ``` Hono: ``` app.get( "/ws", upgradeWebSocket((c) => { const rawProtocols = c.req.header("sec-websocket-protocol"); console.log(rawProtocols); return { onMessage: (event) => { console.log(event.data); }, }; }) ); ``` - Fails right away at the upgrade with `Error: The script will never generate a response.` on the server. - This only happens if I send a subprotocol such as `"potato"` which automatically gets converted to the `sec-websocket-protocol` header as it should. Curiously I can see the header in the console log. - Also tried with hc, same issue.

A

ambergristle•2/2/25, 2:58 PM

hey! i came across this, which might help: https://github.com/cloudflare/cloudflare-docs/pull/15014

A

ambergristle•2/2/25, 3:00 PM

try manually closing the ws server-side in a

close

close

event handler

Aambergristle hey! i came across this, which might help: https://github.com/cloudflare/cloudfl...

P

playsonmacOP•2/2/25, 4:58 PM

Thanks! Do you mean adding a

onClose

onClose

onClose

onClose method tot he return of the

upgradeWebSocket

upgradeWebSocket

upgradeWebSocket

upgradeWebSocket handler? I have it (I just trimmed down the minimal example so it doesn't take up space) and I still have the issue.
Or do you mean something else?

Pplaysonmac Thanks! Do you mean adding a `onClose` method tot he return of the `upgradeWebSo...

A

ambergristle•2/2/25, 8:13 PM

onClose

onClose

onClose

onClose, closing the server: https://developers.cloudflare.com/workers/observability/errors/#cause-2-websocket-connections-that-are-never-closed

Aambergristle `onClose`, closing the server: https://developers.cloudflare.com/workers/observa...

P

playsonmacOP•2/2/25, 8:16 PM

Yep, I have it. Everything works until I send a protocol (which I'm trying to use to authenticate the user since websockets don't support typical headers)

app.get(
  "/ws",
  upgradeWebSocket((c) => {
    // console.log("c.req", c.req);
    const rawProtocols = c.req.header("sec-websocket-protocol");
    console.log(rawProtocols);

    return {
      onMessage: (evt, ws) => {
        console.log("evt in onMessage", evt);
        console.log("ws in onMessage", ws);
      },

      onError(evt, ws) { // < ----------------------- here it is

        console.log("evt in onError", evt);
        console.log("ws in onError", ws);
      },
      onClose(evt, ws) {
        console.log("evt in onClose", evt);
        console.log("ws in onClose", ws);
      },
    };
  })
);

app.get(
  "/ws",
  upgradeWebSocket((c) => {
    // console.log("c.req", c.req);
    const rawProtocols = c.req.header("sec-websocket-protocol");
    console.log(rawProtocols);

    return {
      onMessage: (evt, ws) => {
        console.log("evt in onMessage", evt);
        console.log("ws in onMessage", ws);
      },

      onError(evt, ws) { // < ----------------------- here it is

        console.log("evt in onError", evt);
        console.log("ws in onError", ws);
      },
      onClose(evt, ws) {
        console.log("evt in onClose", evt);
        console.log("ws in onClose", ws);
      },
    };
  })
);

app.get(
  "/ws",
  upgradeWebSocket((c) => {
    // console.log("c.req", c.req);
    const rawProtocols = c.req.header("sec-websocket-protocol");
    console.log(rawProtocols);

    return {
      onMessage: (evt, ws) => {
        console.log("evt in onMessage", evt);
        console.log("ws in onMessage", ws);
      },

      onError(evt, ws) { // < ----------------------- here it is

        console.log("evt in onError", evt);
        console.log("ws in onError", ws);
      },
      onClose(evt, ws) {
        console.log("evt in onClose", evt);
        console.log("ws in onClose", ws);
      },
    };
  })
);

app.get(
  "/ws",
  upgradeWebSocket((c) => {
    // console.log("c.req", c.req);
    const rawProtocols = c.req.header("sec-websocket-protocol");
    console.log(rawProtocols);

    return {
      onMessage: (evt, ws) => {
        console.log("evt in onMessage", evt);
        console.log("ws in onMessage", ws);
      },

      onError(evt, ws) { // < ----------------------- here it is

        console.log("evt in onError", evt);
        console.log("ws in onError", ws);
      },
      onClose(evt, ws) {
        console.log("evt in onClose", evt);
        console.log("ws in onClose", ws);
      },
    };
  })
);

Pplaysonmac Yep, I have it. Everything works until I send a protocol (which I'm trying to us...

A

ambergristle•2/2/25, 8:17 PM

where is it? i don't see it

A

ambergristle•2/2/25, 8:17 PM

also, can you syntax highlight your snippets?

Aambergristle where is it? i don't see it

P

playsonmacOP•2/2/25, 8:20 PM

I've highlighted it above. It's the onClose from the docs - https://hono.dev/docs/helpers/websocket

A

ambergristle•2/2/25, 8:20 PM

from the docs i linked above:

  server.addEventListener("close", () => {
    // This missing line would keep a WebSocket connection open indefinitely
    // and results in "The script will never generate a response" errors
    // server.close();
  });

  server.addEventListener("close", () => {
    // This missing line would keep a WebSocket connection open indefinitely
    // and results in "The script will never generate a response" errors
    // server.close();
  });

  server.addEventListener("close", () => {
    // This missing line would keep a WebSocket connection open indefinitely
    // and results in "The script will never generate a response" errors
    // server.close();
  });

  server.addEventListener("close", () => {
    // This missing line would keep a WebSocket connection open indefinitely
    // and results in "The script will never generate a response" errors
    // server.close();
  });

A

ambergristle•2/2/25, 8:21 PM

where do you

server.close()

server.close()

server.close()

server.close()?

P

playsonmacOP•2/2/25, 8:29 PM

Oh, do you mean on the frontend?

Here's my frontend implementation:

const handleWS = async () => {
    const wsUrl = `${process.env.NEXT_PUBLIC_API_URL}/ws`;

    const ws = new WebSocket(wsUrl, ["Authorization", "sometoken"]);

    // Just added this but doesn't really help..
    ws.addEventListener("close", () => {
      ws.close();
    });

    ws.onopen = () => {
      setWsStatus("Open");
      const initMessage = JSON.stringify({
        type: "init",
        payload: { userId: "user-123", message: "Test message from client" },
      });
      ws.send(initMessage);
    };

    ws.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        switch (data.type) {
          case "ack":
            console.log("Ack received:", data.payload.responseId);
            break;
          case "data":
            setStreamData((prev) => prev + data.payload.chunk);
            break;
          case "complete":
            setWsStatus("Completed");
            break;
          case "error":
            console.error("Error from server:", data.payload.message);
            setWsStatus(`Error: ${data.payload.message}`);
            break;
          default:
            console.warn("Unknown message type:", data.type);
        }
      } catch (err) {
        console.error("Failed to parse message:", err);
      }
    };

    ws.onclose = (event) => {
      console.log(`WebSocket closed: ${event.code} - ${event.reason}`);
      setWsStatus(`Closed: ${event.code} - ${event.reason}`);
    };

    ws.onerror = (event) => {
      console.log("WebSocket encountered error:", JSON.stringify(event));
      setWsStatus("Error encountered");
    };
  };

const handleWS = async () => {
    const wsUrl = `${process.env.NEXT_PUBLIC_API_URL}/ws`;

    const ws = new WebSocket(wsUrl, ["Authorization", "sometoken"]);

    // Just added this but doesn't really help..
    ws.addEventListener("close", () => {
      ws.close();
    });

    ws.onopen = () => {
      setWsStatus("Open");
      const initMessage = JSON.stringify({
        type: "init",
        payload: { userId: "user-123", message: "Test message from client" },
      });
      ws.send(initMessage);
    };

    ws.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        switch (data.type) {
          case "ack":
            console.log("Ack received:", data.payload.responseId);
            break;
          case "data":
            setStreamData((prev) => prev + data.payload.chunk);
            break;
          case "complete":
            setWsStatus("Completed");
            break;
          case "error":
            console.error("Error from server:", data.payload.message);
            setWsStatus(`Error: ${data.payload.message}`);
            break;
          default:
            console.warn("Unknown message type:", data.type);
        }
      } catch (err) {
        console.error("Failed to parse message:", err);
      }
    };

    ws.onclose = (event) => {
      console.log(`WebSocket closed: ${event.code} - ${event.reason}`);
      setWsStatus(`Closed: ${event.code} - ${event.reason}`);
    };

    ws.onerror = (event) => {
      console.log("WebSocket encountered error:", JSON.stringify(event));
      setWsStatus("Error encountered");
    };
  };

const handleWS = async () => {
    const wsUrl = `${process.env.NEXT_PUBLIC_API_URL}/ws`;

    const ws = new WebSocket(wsUrl, ["Authorization", "sometoken"]);

    // Just added this but doesn't really help..
    ws.addEventListener("close", () => {
      ws.close();
    });

    ws.onopen = () => {
      setWsStatus("Open");
      const initMessage = JSON.stringify({
        type: "init",
        payload: { userId: "user-123", message: "Test message from client" },
      });
      ws.send(initMessage);
    };

    ws.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        switch (data.type) {
          case "ack":
            console.log("Ack received:", data.payload.responseId);
            break;
          case "data":
            setStreamData((prev) => prev + data.payload.chunk);
            break;
          case "complete":
            setWsStatus("Completed");
            break;
          case "error":
            console.error("Error from server:", data.payload.message);
            setWsStatus(`Error: ${data.payload.message}`);
            break;
          default:
            console.warn("Unknown message type:", data.type);
        }
      } catch (err) {
        console.error("Failed to parse message:", err);
      }
    };

    ws.onclose = (event) => {
      console.log(`WebSocket closed: ${event.code} - ${event.reason}`);
      setWsStatus(`Closed: ${event.code} - ${event.reason}`);
    };

    ws.onerror = (event) => {
      console.log("WebSocket encountered error:", JSON.stringify(event));
      setWsStatus("Error encountered");
    };
  };

const handleWS = async () => {
    const wsUrl = `${process.env.NEXT_PUBLIC_API_URL}/ws`;

    const ws = new WebSocket(wsUrl, ["Authorization", "sometoken"]);

    // Just added this but doesn't really help..
    ws.addEventListener("close", () => {
      ws.close();
    });

    ws.onopen = () => {
      setWsStatus("Open");
      const initMessage = JSON.stringify({
        type: "init",
        payload: { userId: "user-123", message: "Test message from client" },
      });
      ws.send(initMessage);
    };

    ws.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        switch (data.type) {
          case "ack":
            console.log("Ack received:", data.payload.responseId);
            break;
          case "data":
            setStreamData((prev) => prev + data.payload.chunk);
            break;
          case "complete":
            setWsStatus("Completed");
            break;
          case "error":
            console.error("Error from server:", data.payload.message);
            setWsStatus(`Error: ${data.payload.message}`);
            break;
          default:
            console.warn("Unknown message type:", data.type);
        }
      } catch (err) {
        console.error("Failed to parse message:", err);
      }
    };

    ws.onclose = (event) => {
      console.log(`WebSocket closed: ${event.code} - ${event.reason}`);
      setWsStatus(`Closed: ${event.code} - ${event.reason}`);
    };

    ws.onerror = (event) => {
      console.log("WebSocket encountered error:", JSON.stringify(event));
      setWsStatus("Error encountered");
    };
  };

Pplaysonmac Oh, do you mean on the frontend? Here's my frontend implementation: ```jsx con...

A

ambergristle•2/2/25, 8:29 PM

no, i mean the backend

A

ambergristle•2/2/25, 8:29 PM

please read the docs i sent you

A

ambergristle•2/2/25, 8:30 PM

i haven't worked w webhooks a ton, so i can't explain it any more clearly than cloudflare does

A

ambergristle•2/2/25, 8:31 PM

i just searched the error message you were seeing, and it took me to a section of the cloudflare docs that addresses that specific error message

P

playsonmacOP•2/2/25, 8:34 PM

I appreciate your help

The issue is I'm only using workers through hono and I don't really know how to surface any of the interals. I'm literally using the hono upgradeWebSocket hanlder on one of the routes of the hono app.

P

playsonmacOP•2/2/25, 8:36 PM

I might fall back to just sending the token as a query param

A

ambergristle•2/2/25, 8:36 PM

i would expect this to work (server-side, in your upgrade options)

{
  onClose: (event, ws) => {
    ws.close();
  }
}

{
  onClose: (event, ws) => {
    ws.close();
  }
}

{
  onClose: (event, ws) => {
    ws.close();
  }
}

{
  onClose: (event, ws) => {
    ws.close();
  }
}

A

ambergristle•2/2/25, 8:38 PM

i assume that

upgradeWebSocket

upgradeWebSocket

upgradeWebSocket

upgradeWebSocket is a fairly minimal wrapper

A

ambergristle•2/2/25, 8:40 PM

yeah, pretty much: https://github.com/honojs/hono/blob/65edaf277a2dd3bb47406379904996ffdd3563e5/src/adapter/cloudflare-workers/websocket.ts#L37

P

playsonmacOP•2/2/25, 8:41 PM

Woah, thanks! I'll look into it!

A

ambergristle•2/2/25, 8:42 PM

the hono codebase is insanely accessible

Websocket subprotocol results in Error: The script will never generate a response

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