is there a way to add maxHeaderSize to HTTPS server

[SantanM]

Hi Team,

• Node.js Version: 12.19.0
• OS: Mac OS
• Scope (install, code, runtime, meta, other?): Runtime
• Module (and version) (if relevant): HTTPS

I would like to know if it is possible to set maxHeaderSize option to the HTTPS server. Out of the box HTTPS module does not have this option, and I am wondering if there is way to do so. The problem I have is, the server throws 431 error response due to the large header size in the incoming request to the HTTPS server.

Is there a solution to my problem? It must be a common problem, but I could not find anyone reporting it anywhere. It seems (according to the documentation) the options of HTTP server are applicable to HTTPS, but the value does not seem to work in my case (seeing 431 error always). How can I verify the maxHeaderSize value using HTTPS server. My code looks like -

const server = https.createServer({
  key: process.env.SSL_PRIVATE_KEY,
  cert: process.env.SSL_PUBLIC_CERT,
  maxHeaderSize: 8192*6
}, app).listen(PORT, () => {
  log.info(`🚀 Approuter started on port ${PORT}`);
console.log(server.maxHeaderSize); // outputs undefined
});

[gireeshpunathil]

@nodejs/http

[mcollina]

This should be possible as the whole machinery is the same. It probably needs some additional documentation fix.

[ShogunPanda]

Hi @gireeshpunathil.

I've tried across different Node version. The problem exists only for Node 12, while it is fixed on 14 and 16. If you look at the documentation and its history, you will notice that maxHeaderSize has been added in 13.3.0, so it's not supported on your Node version.
Given that 12 is now not supported anymore, if you update to Node 16 (the Active LTS) or at least 14 (the Maintenance LTS), the problem should go away by itself.

For anybody else interested in reproducing the issue, you can use code below:

import { readFileSync } from 'fs'
import { createServer } from 'https'
import undici from 'undici'

const server = createServer(
  {
    key: readFileSync('ssl/privkey.pem'),
    cert: readFileSync('ssl/fullchain.pem'),
    maxHeaderSize: 8192 * 6
  },
  (req, res) => {
    res.writeHead(200)
    res.end(`X-Payload header size: ${req.headers['x-payload'].length}`)
  }
).listen(0, async () => {
  const port = server.address().port
  console.log(`Server is listening on port ${port} using Node ${process.version} ...`)

  const payload = Buffer.alloc(8192 * 5, '123').toString('utf-8')

  const {
    statusCode,
    headers,
    body: data
  } = await undici.request(`https://home.cowtech.it:${port}`, {
    headers: { 'x-payload': payload },
    dispatcher: new undici.Agent({ pipelining: 0 })
  })

  let body = Buffer.alloc(0)
  for await (const chunk of data) {
    body = Buffer.concat([body, chunk])
  }

  console.log('Received reply:\n\n' + JSON.stringify({ statusCode, headers, body: body.toString('utf-8') }, null, 2))
  server.close()
})