Wordpress auto-config for dev/test/live environments

wp-config.php

<?php
/**
 * The base configurations of the WordPress.
 *
 * This file has the following configurations: MySQL settings, Table Prefix,
 * Secret Keys, WordPress Language, and ABSPATH. You can find more information
 * by visiting {@link http://codex.wordpress.org/Editing_wp-config.php Editing
 * wp-config.php} Codex page. You can get the MySQL settings from your web host.
 *
 * This file is used by the wp-config.php creation script during the
 * installation. You don't have to use the web site, you can just copy this file
 * to "wp-config.php" and fill in the values.
 *
 * @package WordPress
 */

// ** MySQL settings - You can get this info from your web host ** //
preg_match("/^domain\.([a-z]+)\.whatev\.local/i", $_SERVER['HTTP_HOST'], $local_network);

switch ($_SERVER['HTTP_HOST'])
{
	case 'domain.com.dev':
		define('DB_NAME',        'dbname');
		define('DB_USER',        'user');
		define('DB_PASSWORD',    'password');
		define('WP_SITEURL',     'http://domain.com.dev/blog');
		define('WP_HOME',        'http://domain.com.dev/blog');
		define('WP_CONTENT_URL', 'http://domain.com.dev/blog/wp-content');
		break;
	case 'domain.' . $local_network[1] . '.whatev.local':
		define('DB_NAME',        'dbname');
		define('DB_USER',        'user');
		define('DB_PASSWORD',    'password');
		define('WP_SITEURL',     'http://domain.' . $local_network[1] . '.whatev.local/blog');
		define('WP_HOME',        'http://domain.' . $local_network[1] . '.whatev.local/blog');
		define('WP_CONTENT_URL', 'http://domain.' . $local_network[1] . '.whatev.local/blog/wp-content');
		break;
	// This should default to the LIVE environment settings
	default:
		define('DB_NAME',        'dbname');
		define('DB_USER',        'username');
		define('DB_PASSWORD',    'password');
		define('WP_SITEURL',     'http://www.domain.com/blog');
		define('WP_HOME',        'http://www.domain.com/blog');
		define('WP_CONTENT_URL', 'http://www.domain.com/blog/wp-content');
		break;
}

define('DB_HOST', 'localhost');
define('DB_CHARSET', 'utf8');
define('DB_COLLATE', '');
define('WP_CONTENT_DIR', $_SERVER['DOCUMENT_ROOT'] . '/blog/wp-content');
define('DISALLOW_FILE_MODS', TRUE);
define('WP_CACHE', true);