These guides will help you configure Chassis for specific types of development.

WordPress Core Development

An SVN or Git checkout of WordPress can be mapped as Chassis’ wp/ directory to enable development of WordPress Core.

Directory Structure

If you’ve installed Chassis into a folder such as wpcore-box, use SVN or Git to clone (or, depending on how you develop) into a sibling directory. For example:

  • wordpress-development/
    • wpcore/: A clone of WordPress from develop.svn or develop.git
    • wpcore-box/: Chassis

Tester Extension

The Tester extension adds and configures PHPUnit for WordPress tests. You can install other extensions if you want, but there’s nothing else required.


Save this configuration as config.local.yaml in the Chassis root directory to configure Chassis to look for WordPress in your wpcore/ checkout.

    # Use the Chassis box normally...
    base: .
    content: content

    # But use my development copy of WordPress for the WP source
    wp: ../wpcore/src

# Also use your development copy of WordPress for the unit test
# framework, and for the unit tests themselves
    ../wpcore: /vagrant/extensions/tester/wpdevel

# Set the host to ``core.local`` to distinguish from other chassis boxes
    - core.local

# Explicitly set database configuration to avoid warning with Tester
    name: wordpress
    user: wordpress
    password: vagrantpassword
    prefix: wp_

# Run in multisite mode (totally optional)
multisite: true

WordPress will now be loaded from the wpcore/ checkout, not the wp/ directory within Chassis. However, in order for WP-CLI and other tools to be able to find Chassis’ wp-config.php we need to add a dummy configuration file at wpcore/src/wp-config.php:

// Fool WP-CLI into recognising this as a valid config file
if ( false ) {
    require ABSPATH . './wp-settings.php';

require '/vagrant/wp-config.php';

In normal circumstances editing Chassis’ own wp-config.php file is discouraged in favor of using local-config.php. However in this case you’re working around WP-CLI with the dummy wp-config.php file, so you will need to make one change to Chassis’ own wp-config.php file to wrap the line which requires wp-settings.php in a conditional check:

if ( ! defined( 'WP_CLI' ) ) {
    require_once( ABSPATH . 'wp-settings.php' );

This will prevent WP-CLI from loading wp-settings.php twice.

With this configuration you should now be ready to develop against WordPress Core.

Vagrant Share

Vagrant Share enables the ability to generate a temporary URL which you can share with people to allow them access to your local Chassis installation.

  1. Install Vagrant Share

    Run the following command in a terminal to install the Vagrant Share plugin. vagrant plugin install vagrant-share.

  2. Install ngrok

    Vagrant Share requires ngrok to be installed on the host machine. You can verify if this is installed by running which ngrok in a terminal. If there is no output then you will need to download and install ngrok. Once you’ve downloaded ngrok unzip it: unzip /path/to/ Move ngrok: mv /path/to/ngrok /usr/local/bin/ngrok

  3. Run Vagrant Share

    You now need to run vagrant share --http=vagrant.local:80. If you’re using a custom domain then you will need to use that e.g. vagrant share --http=<your-custom-domain>.local:80. You will then have a temporary URL generated for you. e.g. http://<id> You need to leave this running in the background.

  4. Share your site

    Navigate to the URL that ngrok generated.


If you see an error when you run vagrant provision then try running it again. If you’re still having trouble accessing the URL try a vagrant reload after you’ve run a successful vagrant provision