create-react-app: Subdomains not working in 1.0.0

Let’s reopen the issue for subdomain use case specifically, as we should indeed support any subdomains of localhost by default. I believe we’re waiting for a WDS pull request to land for this.

But in the meantime you can add DANGEROUSLY_DISABLE_HOST_CHECK=true to your env file if this is blocking you.

Even though the allowedHosts feature landed in WDS, there is no way to use that feature from an unejected create-react-app, as far as I know.

This means if you want to use the proxy feature (to forward requests to a backend API, for example), WDS will check the host, and subdomains (e.g. subdomain.localhost) will not be allowed. This could be allowed with a WDS config by setting allowedHosts to ".localhost", for example, but there isn’t a way to pass in this config via create-react-app.

I have a proposed solution here: https://github.com/facebookincubator/create-react-app/pull/2288. What do you think?

Here is a quick and dirty workaround if you need to run your dev app on domains other than localhost :

1. Install concurrently and http-proxy

   yarn add concurrently http-proxy || npm install --save-dev concurrently http-proxy
   

2. Add proxy-server.js

   var http = require('http');
   var httpProxy = require('http-proxy');
   
   httpProxy.createServer({
     changeOrigin: true,
     hostRewrite: true,
     autoRewrite: true,
     ws: true,
     target: 'http://localhost:3000'
   }).listen(process.env.PORT || 8080);
   

3. Replace the start script in your package.json by this

   {
     // ...
     "scripts": {
       "start": "concurrently \"node proxy-server.js\" \"PORT=3000 react-scripts start\"",
       // ...
   

We will need https://github.com/webpack/webpack-dev-server/pull/899 to make this happen. 😄

A separate PR just to add .localhost support (or making this the default behavior) might also be warranted.