API resolved without sending a response in Nextjs

Question

I have to make same changes in my nextjs project because my enpoint API doesn't support many calls and I would like to make a refresh from the original data every 3 min.

I implemented API from nextjs: I create a pages/api/data and inside I make the call to my endpoint, and in my getInitialProps inside index call to data file.

The get works okey, but I have 2 problems:

1: I have and alert message that says:

API resolved without sending a response for /api/data, this may result in stalled requests.

2: It dosen 't reload data after 3 min..I supouse it is beacuse Cache-Control value...

This is my code:

pages/api/data

import { getData } from "../../helper";

export default async function(req, res) {
  getData()
    .then(response => {
      res.statusCode = 200
      res.setHeader('Content-Type', 'application/json');
      res.setHeader('Cache-Control', 'max-age=180000');
      res.end(JSON.stringify(response))
    })
    .catch(error => {
      res.json(error);
      next();
    });
};

pages/index

import React, { useState, useEffect } from "react";
import fetch from 'isomorphic-unfetch'

const Index = props => {

  return (
    <>Hello World</>
  );
};

 Index.getInitialProps = async ({ res }) => {
  const response = await fetch('http://localhost:3000/api/data')
  const users = await response.json()
  return { users }
};

export default Index;

Answer 1

You should return a Promise and resolve/reject it.

Example:

import { getData } from "../../helper";

export default async function(req, res) {
  return new Promise((resolve, reject) => {
    getData()
      .then(response => {
        res.statusCode = 200
        res.setHeader('Content-Type', 'application/json');
        res.setHeader('Cache-Control', 'max-age=180000');
        res.end(JSON.stringify(response));
        resolve();
      })
      .catch(error => {
        res.json(error);
        res.status(405).end();
        resolve(); // in case something goes wrong in the catch block (as vijay commented)
      });
  });
};