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Corrupted file served if file is changed during serving.

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
javascript, node.js, wasm
Domain
backend

Research direction

Start by reproducing the issue with the shown serveStatic(root) setup and a 100MB+ WASM file that changes while a request is in progress. Inspect the serve-static behavior involved in serving and reloading the file, then verify that a browser refresh receives the complete rebuilt file without restarting the server.

Written by the indexing model from the issue text.

Description

awaiting more info

Hi, I've got such a code for my server:

import path from 'node:path'
import url from 'node:url'
import portfinder from 'portfinder'
import connect from 'connect'
import { WebSocketServer } from 'ws'
import serveStatic from 'serve-static'
import logger from 'morgan'

export const DEFAULT_PORT = 8080

let dirname = path.dirname(url.fileURLToPath(import.meta.url))
// Path of a file that needs to be injected into the bundle for live-reload to work.
export const LIVE_RELOAD_LISTENER_PATH = path.join(dirname, 'live-reload.js')

export async function start({ root, assets, port }) {
    assets = assets ?? path.join(root, 'assets')

    const freePort = await portfinder.getPortPromise({ port: port ?? DEFAULT_PORT })

    const setHeaders = (res) => {
        res.setHeader('Cache-Control', 'no-store')
    }

    const app = connect()
        .use(logger('dev', { skip: (req, res) => res.statusCode < 400 }))
        .use(serveStatic(root, {setHeaders}))
        .use('/assets', serveStatic(assets, {setHeaders}))

    const server = app.listen(freePort)
    const wsServer = new WebSocketServer({ server, clientTracking: true, path: '/live-reload' })

    var serverUrl = `http://localhost:${freePort}`
    console.log('Serving %s', serverUrl)

    return {
        port: freePort,
        reload() {
            wsServer.clients.forEach(sock => sock.send('reload'))
        },
    }
}

And we have observed a very interesting behavior. Namely, when it is serving our WASM file (100MB+), if the WASM is being re-build just when serving starts, then it is served to the browser corrupted. What's interesting is that after it is rebuilt, browser refreshes dont help - the same corrupted file is being served. What helps is restarting the above server to serve non-corrupted file. Does anyone have any idea why this happens and if this can be prevented somehow? I'm OK with serving it in a corrupted state for the first time (during rebuild), but I want the file to be served correctly after page reload.

Dominant language
JavaScript
Stars
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Forks
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Avg merge
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Merged PRs (30d)
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