NextJS: API resolved without sending a response for /xx/xx, this may result in stalled requests.

[anonymouscatcher]

Checks

• I understand project setup issues should be asked on StackOverflow or in GitHub Discussions.
• I updated to latest http-proxy-middleware.

Describe the bug (be clear and concise)

I'm trying to setup local proxy while it's working fine for all the requests, it doesn't work for POST requests including data. I have disabled bodyParser but it didn't help.

I also created an issue about this but it doesn't seems to be next.js issue but I'm not sure.
Issue:
vercel/next.js#36811
Discussion:
vercel/next.js#36859

Step-by-step reproduction instructions

1. create api in next project
2. send a post request including data (like a login api)
3. you will see that the request won't be resolved

Expected behavior (be clear and concise)

I expect to resolve the api with a response.

How is http-proxy-middleware used in your project?

=> Found "http-proxy-middleware@2.0.6"
info Has been hoisted to "http-proxy-middleware"
info This module exists because it's specified in "devDependencies".
info Disk size without dependencies: "184KB"
info Disk size with unique dependencies: "592KB"
info Disk size with transitive dependencies: "2.83MB"
info Number of shared dependencies: 11
✨  Done in 0.44s.

### What http-proxy-middleware configuration are you using?

```typescript
const proxy = createProxyMiddleware({
      logLevel: 'debug',
      target: 'XXX',
      changeOrigin: true,
      autoRewrite: true,
    });

export default proxy;

What OS/version and node/version are you seeing the problem?

macOS, node 16

Additional context (optional)

No response

[chimurai]

Could you provide a minimal reproduction of the issue?

[anonymouscatcher]

@chimurai Here you go, https://github.com/alirezavlz/next-proxy-issue
run the app on dev mode and run the server.js, you will see that get request is working but post request doesn't work. it stucks in pending.

[anonymouscatcher]

@chimurai could you have a look to repo? :)

[chimurai]

Could you provide a minimal reproduction of the issue?

I'm not really a Next.js user. Had a quick look and do see the POST is "hanging".

Are you able to recreate this issue with a minimal setup? A simple express + http-proxy-middleware and a basic POST request?

To isolate a Next.js configuration/integration issue from http-proxy-middleware issue/bug.

[chimurai]

With a simple express proxy server I'm able to proxy to your target server.

const express = require('express');
const { createProxyMiddleware } = require('http-proxy-middleware');

const app = express();

app.use(createProxyMiddleware({
    target: 'http://localhost:9090'
}));

app.listen(3000, () => {
    console.log('Server started and listening on port 3000')
});

curl -XPOST 'http://localhost:3000/api2/login'

$ {"response":"I should be returned as a response","data":{}}

[anonymouscatcher]

Yeah it’s so weird I’m not sure it’s an issue of next js or this library, but if I create the proxy externally it will work fine. (Not in the /api directory in next js)
😞

[anonymouscatcher]

I have tested the same logic with https://github.com/http-party/node-http-proxy and it worked correctly. so I think the issue should be with http-proxy-middleware.

[chimurai]

Can you share minimal working code with node-http-proxy?
Issue can be investigated, you can recreated it with a curl command firing requests to the server. (without react)

[anonymouscatcher]

@chimurai I'm currently using this version of node-http-proxy which is for next js. but It uses that in top of that.

https://github.com/stegano/next-http-proxy-middleware

const proxy = (req, res) => {
  return httpProxyMiddleware(req, res, {
    target: process.env.DEFAULT_API_ENDPOINT,
    onProxyInit,
    cookieDomainRewrite,
    changeOrigin: true,
    pathRewrite: [
      {
        patternStr: '^/api/json',
        replaceStr: ''
      }
    ]
  });
};

export default proxy;

There is nothing fancy in the code it's just these couple of lines.

[JacerOmri]

I was stuck with this for a while. I was able to solve it using API config (in Next.js), I had to disable bodyParser.

export const config = {
  api: {
    externalResolver: true,
    bodyParser: false, // I added this
  },

[jag-ermeister]

I was stuck with this for a while. I was able to solve it using API config (in Next.js), I had to disable bodyParser.

export const config = {
  api: {
    externalResolver: true,
    bodyParser: false, // I added this
  },

Just in case anybody is unable to read like me, I originally misinterpreted this and added bodyParser: false to the middleware configuration, which did not help. Adding this to the Next.js API config like @JacerOmri mentioned was the fix!

[chimurai]

Updated the Next.js recipe.

Thanks for sharing the solution!