"API resolved without sending a response" appearing on every route despite the API routes working fine.

[drkgrntt]

I recently switched from an Express server to NextJS's API pages, and I love the way this repo helps with that, so thank you!

That said, all of my API routes are logging "API resolved without sending a response". This issue was posted 3 days ago in nextjs's issues and was closed the next day with this comment being the solution to it. I was wondering if the solution could be implemented into this repo. It looks like the OP was using async/await and the comment that solved the problem recommended returning a Promise instead. In my particular case, all my my routes are printing the message, regardless of if they are asynchronous or not. One example is the following:

import connect from "next-connect"
import common from "../../../middleware/common/"
import keys from "../../../config/keys"

const handler = connect()
handler.use(common)

handler.post((req, res) => {
  return res.status(200).send(keys.googleMapsKey)
})

export default handler

It's possible my problem lies elsewhere, but since all of my routes are going through next-connect, I figured this might be something to be looked at within the repo.

[hoangvvo]

import connect from "next-connect"
import common from "../../../middleware/common/"
import keys from "../../../config/keys"

const handler = connect()
handler.use(common)

handler.post((req, res) => {
  return res.status(200).send(keys.googleMapsKey)
})

export default (req, res) => handler.apply(req, res) 

Hi @drkgrntt, can you try doing this instead?

[franklinjavier]

It worked with handler.apply

[drkgrntt]

This seems to work! In the readme, .apply(req, res) is only mentioned at the very end for middleware and getInitialProps. Is there something I missed that would indicate that I need to do that in all of my API endpoints?

[hoangvvo]

@drkgrntt I did not include this because it was not the case until #9999. See this comment

handler does not resolve into a promise, but acts more like a callback thing, so Next.js throws that warning.

Howevere, it is just a harmless warning and should not cause any actual error in production as long as we handle every thing right in creating the middleware

[drkgrntt]

Great! Thank you for the quick responses.

[throwarray]

The .apply fix mentioned doesn't handle errors and leads to requests hanging.
The intention here would be to have 'not found' returned since there's no GET handler

const router = nextConnect()

router.post(function (req, res) { res.end('ok') })

export default function (req, res) { return router.apply(req, res) }

Maybe a method could be added that basically does this

connect.apply = function apply(req, res) {
  return new Promise((resolve) => this.handle(req, res, function (err) {
      if (err) onError(err, req, res)
      
      else onNoMatch(req, res)

      resolve()
  }))
}

[hoangvvo]

@throwarray Thanks, will be handled in #38.
.apply is not always use as a route handler so I would not call .onError. However, it should reject the promise.

[hoangvvo]

The next version will always return a promise so we do not need to use .apply to avoid that error anymore