Ngrok for drupal

What is ngrok ?

Ngrok allows developers to create secure tunnels to localhost or platform of their choice. Main use cases of ngrok are:

Demo without deploying

Simplify mobile device testing
Build webhook integrations with ease
Run personal cloud services from your own private network
More info at https://ngrok.com

What's wrong when using ngrok with drupal ?

If your setup uses VirtualHost for development, you need to rewrite headers to point ngrok to the site you want to expose.

ngrok http -host-header=rewrite my.domain.local:80

This leads to blocking problems when trying to initiate sessions (cookies sessions can't be set due domain mismatch) or exposing absolute URLs that still points to local domain instead of external ngrok.io one.

What's the purpose of this module ?

This module alters the behaviour of Drupal core to resolve the issues described above. When a ngrok session is initiated, it:

Redefine the cookie_domain to your subdomain.ngrok.io
Alter external URLs to use the subdomain.ngrok.io as base URL
How is it achieved and how to use this module ?
This module is composed of two parts, a Drupal module and a core patch.

The Drupal module simply extends the session_configuration and url_generator.non_bubling services. They inspect request headers to check if a 'x-original-host' header was sent and then alter the cookie_domain or host values.

The patch alter the \Drupal\Component\Utility\UrlHelper::externalIsLocal method to allow the external ngrok.io url that is currently in use in the request