Engine.io crashing my app with ERR_STREAM_WRITE_AFTER_END

[michioxd]

At some point, my application crashes and shows something like this:

Bun v1.1.39 (Linux x64)
131 |                 // unwanted download dialog on certain user-agents (GH-43)
132 |                 "Content-Type": "text/html",
133 |                 "Content-Length": "2",
134 |             };
135 |             res.writeHead(200, this.headers(req, headers));
136 |             res.end("ok");
                      ^
error: write after end
 code: "ERR_STREAM_WRITE_AFTER_END"

      at new NodeError (node:stream:247:16)
      at _write (node:stream:2399:15)
      at node:stream:2565:23
      at onEnd (....../node_modules/.pnpm/[email protected]/node_modules/engine.io/build/transports/polling.js:136:17)
      at emit (node:events:72:22)
      at endReadableNT (node:stream:2211:47)
      at processTicksAndRejections (native:7:39)

Bun v1.1.39 (Linux x64)

I'm using Bun 1.1.39 and Socket.IO 4.8.0
How to fix it? Thanks

[michioxd]

Temporary solved by catching process uncaughtException event.

import process from 'node:process';

process.on('uncaughtException', (err, origin) => {
    // something or console.error...
});

[darrachequesne]

It seems the replacement of Node.js HTTP server provided by bun is a bit more restrictive regarding writing to an already closed response. Are you able to reproduce the issue locally?

[michioxd]

My server just setup like this:

import express from "express";
import { Server, type Socket } from "socket.io";
import http from "http";

const app = express();
export const server = http.createServer(app);
export const io = new Server(server, {
    path: '/api/v3/socket',
    transports: ['websocket', 'polling']
});

And start with bun

bun ./src/index.ts

Sometimes it happens and crashes my app (before the exception is caught). I don't know why it's happening because it occurs on my production server, which is being used by many users.