API resolved without sending a response (another one)

[jordymeow]

I am not the only one with this issue, but other threads didn't fix my issue. I feel like there might be some issues in the library. Hopefully, it's simply in my code...

Describe the bug

I am using next-connect as well, as I need middlewares (I guess most of us need that library as well). I am always getting this warning:

API resolved without sending a response...

To Reproduce

const Handler = nextConnect();
Handler.use(middleware);

Handler.get(async (req, res) => {
  return new Promise(async resolve => {
    res.status(200).json({});
    return resolve();
  });
});

export default Handler;

I have simplified the code, of course, there are async calls in that function as well, otherwise, I wouldn't use an async function here ;) But this simple example doesn't work either.

I am currently using NextJS 9.2.1 and Next Connect 0.6.0.

[Janpot]

Can't reproduce with

import nextConnect from "next-connect";
const handler = nextConnect();

handler.get(async (req, res) => {
  return new Promise(resolve => {
    res.status(200).json({});
    return resolve();
  });
});

export default handler;

You probably want to share a full reproduction , including the code for middleware.

[jordymeow]

Thanks for your help @Janpot, but yes, the issue is linked to the middleware, and the fact NextJS is currently not completely compatible with next-connect.

There is a pull request for it: here.

Hopefully, this will be accepted, and more collaboration will be done with the next-connect library. I am not sure how it is possible to build a product based on NextJS without any middleware, or maybe there is a better alternative?

[naxmefy]

The problem happens if you use another handler inside the handler

import nextConnect from 'next-connect'

const handler = nextConnect()

handler.use(nextConnect())
handler.get((req, res) => {
    res.status(204).end()
})

export default handler

it does not print the warning if you use only one handler (and add each middleware separately)

another example (with one handler)

[jordymeow]

Exactly :) Personally I have stopped using next-connect, and I made my own middlewares. Fewer dependencies, and it's just as easy. That module is cool, but if NextJS doesn't care much about it, I prefer to build solutions avoiding it.

[naxmefy]

Exactly :) Personally I have stopped using next-connect, and I made my own middlewares. Fewer dependencies, and it's just as easy. That module is cool, but if NextJS doesn't care much about it, I prefer to build solutions avoiding it.

may you give an example of how you do it?

[jordymeow]

Actually, I don't do anything magical. I am just doing basically this: https://nextjs.org/docs/api-routes/api-middlewares. But I have created a little HOC for my API requests, and I basically add everything I need, like the DB, Auth, etc, and make sure those "modules" are singletons.

[hoangvvo]

Hey, I am the author of next-connect. I just push the fix for this issue in 0.6.1

[jordymeow]

Thank you so much @hoangvvo! :) I will definitely give it another try.

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.