Invalid Host Header when ngrok tries to connect to React dev server

Question

I'm trying to test my React application on a mobile device. I'm using ngrok to make my local server available to other devices and have gotten this working with a variety of other applications. However, when I try to connect ngrok to the React dev server, I get the error:

Invalid Host Header 

I believe that React blocks all requests from another source by default. Any thoughts?

Answer 1

im encountering a similar issue and found two solutions that work as far as viewing the application directly in a browser

ngrok http 8080 -host-header="localhost:8080"
ngrok http --host-header=rewrite 8080

obviously replace 8080 with whatever port youre running on

this solution still raises an error when i use this in an embeded page, that pulls the bundle.js from the react app. i think since it rewrites the header to localhost, when this is embeded, its looking to localhost, which the app is no longer running on

Answer 2

I used this set up in a react app that works. I created a config file named configstrp.js that contains the following:

module.exports = {
ngrok: {
// use the local frontend port to connect
enabled: process.env.NODE_ENV !== 'production',
port: process.env.PORT || 3000,
subdomain: process.env.NGROK_SUBDOMAIN,
authtoken: process.env.NGROK_AUTHTOKEN
},   }

Require the file in the server.

const configstrp      = require('./config/configstrp.js');
const ngrok = configstrp.ngrok.enabled ? require('ngrok') : null;

and connect as such

if (ngrok) {
console.log('If nGronk')
ngrok.connect(
    {
    addr: configstrp.ngrok.port,
    subdomain: configstrp.ngrok.subdomain,
    authtoken: configstrp.ngrok.authtoken,
    host_header:3000
  },
  (err, url) => {
    if (err) {

    } else {

    }
   }
  );
 }

Do not pass a subdomain if you do not have a custom domain