Subdomains not working in 1.0.0

Description

Since 1.0.0 we cannot visit subdomains on the dev server anymore. This is usfeful for devs who use subdomains to serve different data based on subdomains with CRA.

Expected behavior

Visiting the app on http://test.localhost:3000/ should display the app the same as the usual: http://localhost:3000/

Actual behavior

Instead of the app we get: Invalid Host header

Reproducible Demo

create a new react app and visit any subdomain.

Extra

• Would it be possible to add an option to the package json to use disableHostCheck: true in the webpackDevServer.config ?
• is it possible to add an option to open the browser on a subdomain?

[gaearon]

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.

[naw]

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.