ERR_STREAM_WRITE_AFTER_END

[aaaaahaaaaa]

First of all: nice lib. AFAICT it's the only clean middleware out there that allows to update the request's headers with NextJS without errors.

I do encounter issues with your middleware though.

I have a fairly simple proxy setup for an API with a dynamic route (using SWR on the client side):

import type { NextApiRequest, NextApiResponse } from 'next'
import jwt from 'next-auth/jwt'
import httpProxyMiddleware from 'next-http-proxy-middleware';

export default async (req: NextApiRequest, res: NextApiResponse) => {
  const { accessToken } = await jwt.getToken({ req: req, secret: "CHANGE_ME" })
  return httpProxyMiddleware(req, res, {
    target: 'https://whatever.com',
    pathRewrite: { "^/before": '/after' },
    headers: { Authorization: `Bearer ${accessToken}` },
  })
}

When sending requests via to the proxy for with the same path, it works nicely. When requests with different paths go through the middleware, I see the following error (not right away, after a couple of minutes):

Error [ERR_STREAM_WRITE_AFTER_END]: write after end
    at new NodeError (node:internal/errors:278:15)
    at write_ (node:_http_outgoing:718:11)
    at ClientRequest.write (node:_http_outgoing:677:15)
    at ProxyServer.<anonymous> (.../next-http-proxy-middleware/build/index.js:1:2419)
    at ProxyServer.emit (.../eventemitter3/index.js:210:27)
    at ClientRequest.<anonymous> (.../http-proxy/lib/http-proxy/passes/web-incoming.js:133:16)
    at ClientRequest.emit (node:events:388:22)
    at tickOnSocket (node:_http_client:781:7)
    at onSocketNT (node:_http_client:820:5)
    at processTicksAndRejections (node:internal/process/task_queues:81:21) {
  code: 'ERR_STREAM_WRITE_AFTER_END'
}

And prior to that, NextJS's server shows this kind of warning:

[...]
API resolved without sending a response for some/target/url, this may result in stalled requests
[...]

[stegano]

Hi @aaaaahaaaaa,
Thanks for your reporting 😀
Could you let me know your code snippet of making request
(or HTTP request packets captured using tcpdump)

[FDiskas]

Try like so

import type { NextApiRequest, NextApiResponse } from 'next'
import jwt from 'next-auth/jwt'
import httpProxyMiddleware from 'next-http-proxy-middleware';

export default async (req: NextApiRequest, res: NextApiResponse) => {
  const { accessToken } = await jwt.getToken({ req: req, secret: "CHANGE_ME" })
  await httpProxyMiddleware(req, res, {
    target: 'https://whatever.com',
    pathRewrite: { "^/before": '/after' },
    headers: { Authorization: `Bearer ${accessToken}` },
  });
  res.end();
}

The main problem is that response is not finished

[FDiskas]

Related vercel/next.js#10439

[aaaaahaaaaa]

Thanks for the feedback. Unfortunately I changed my implementation and have no means to test this at the moment. I'll try again when I have a minute. I'll close this issue for now.

[stegano]

This issue may have been resolved by #24.

[FDiskas]

v^1.0.10 - still getting

this may result in stalled requests.

import httpProxyMiddleware from 'next-http-proxy-middleware';
import { NextApiRequest, NextApiResponse } from 'next';
import { getSession } from '@auth0/nextjs-auth0';
import * as Sentry from '@sentry/node';

import { initSentry } from 'src/utils/sentry';

export default async (req: NextApiRequest, res: NextApiResponse) =>
    httpProxyMiddleware(req, res, {
        target: process.env.NEXT_PUBLIC_API_BASE_URL,
        // In addition, you can use the `pathRewrite` option provided by `next-http-proxy`
        pathRewrite: {
            '^/api/rest': '/api',
        },
        headers: {
            Authorization: `Bearer ${getSession(req, res)?.idToken}`,
            'Content-Type': 'application/json-patch+json',
        },
    }).catch(async (error) => {
        initSentry();

        Sentry.captureException(error);

        await Sentry.flush(2000);
    });

if I add res.end() then after some time I get

http-proxy/lib/http-proxy/index.js:120
    throw err;
    ^

Error: socket hang up
    at connResetException (internal/errors.js:617:14)
    at TLSSocket.socketCloseListener (_http_client.js:443:25)
    at TLSSocket.emit (events.js:327:22)
    at TLSSocket.EventEmitter.emit (domain.js:486:12)
    at net.js:673:12
    at TCP.done (_tls_wrap.js:563:7) {
  code: 'ECONNRESET'

[OliverDudgeon]

Also getting API resolved without sending a response for some/target/url, this may result in stalled requests type issues with a similar setup.

[FDiskas]

I added

export​ ​const​ ​config​ ​=​ ​{​
    ​api​: ​{​
        ​bodyParser​: ​false​,​
        ​externalResolver​: ​true​,​
    ​}​,​
​}​;​

On top of file and thous errors is not displayed anymore, but not sure is the problem is solved that way