Calling nodeJS HTTP server from Javascript

Question

I am trying to setup a very simple nodeJS HTTP server. When I call it from the browser, like this http://localhost:8081, it works fine, but when I call is using a JS fetch() method, I get a 404 error:

GET http://localhost/:8081?q=hi

JS:

fetch(":8081/?q=hi")

NODE JS:

const requestListener = function (req, res) {
  res.writeHead(200);
  res.end('Hello, World!');
  }
const server = http.createServer(requestListener);
server.listen(8081);

How do you run this fetch? It's a website hosted somewhere? Or served by some local server? — Konrad, Sep 22 '22 at 20:19
it's in a js file. I've tried putting it on a server an running locally, but get the same result — Bill Ferster, Sep 22 '22 at 20:21

score 0 · Answer 1 · answered Sep 22 '22 at 20:19

0

When you're calling your local server through JS fetch, you don't need to add the port number you can call it like below:

fetch('/?q=hi')

answered Sep 22 '22 at 20:19

DreamCode

25
3

the nodejs server is attached to 8081 – Bill Ferster Sep 22 '22 at 20:22
it wont matter if its on the same domain (includes the port), so this answer is valid 100% – Eslam Abu Hugair Sep 22 '22 at 20:23
The only way I can get the server to respond to the fetch is with and explicit url AND a no cores mode fetch(`http://localhost:8081?,{mode:"no-cors"}) – Bill Ferster Sep 22 '22 at 21:10

score 0 · Answer 2 · answered Sep 22 '22 at 20:22

0

the URL handed to fetch function looks wronge, it would work if you adjust it to:

fetch('http://localhost:8081/?q=hi');

// or

fetch('/?q=hi');

it should work just fine, and ensure that you enable the cors if you need to works from any domain

answered Sep 22 '22 at 20:22

Eslam Abu Hugair

1,162
1
11
23

Umar Farooque Khan · Accepted Answer · 2022-09-22T20:36:44.553

Every thing is fine, you just need to enable cors that's it, use the below code

const http = require('http')
const requestListener = function (req, res) {
    const headers = {
        'Access-Control-Allow-Origin': '*', /* @dev First, read about security */
        'Access-Control-Allow-Methods': 'OPTIONS, POST, GET',
        'Access-Control-Max-Age': 2592000, // 30 days
        /** add other headers as per requirement */
    };
    res.writeHead(200, headers);
    res.end(JSON.stringify({"key":"value"}));
}
const server = http.createServer(requestListener);
server.listen(8081);

If you are running both frontend and backend code on the same server then you don’t have to use complete url while if you are running fronted and backed on different server you need to enable cors and use complete url.

Calling nodeJS HTTP server from Javascript

3 Answers3