WordPress Configuration for Multiple Environments

wp-config.php

<?php
	// Define Environment Variables
	$environment = new stdClass();
	$environment->local = '/wp-config-local.php';
	$environment->staging = '/wp-config-staging.php';
	$environment->testing = '/wp-config-testing.php';

	// Dynamically Set Environment Constants
	define( 'WP_ENV_LOCAL', file_exists( ABSPATH . $environment->local ) );
	define( 'WP_ENV_STAGING', file_exists( ABSPATH . $environment->staging ) );
	define( 'WP_ENV_TESTING', file_exists( ABSPATH . $environment->testing ) );

	if ( WP_ENV_LOCAL ) {
		require( ABSPATH . $environment->local );

	} elseif ( WP_ENV_STAGING ) {
		require( ABSPATH . $environment->staging );

	} elseif ( WP_ENV_TESTING ) {
		require( ABSPATH . $environment->testing );

	} else {
		define( 'DISALLOW_FILE_EDIT', true );
		define( 'DISALLOW_FILE_MODS', true );

		// Production Environment
		$mysql_hostname = '';
		$mysql_username = '';
		$mysql_password = '';
		$mysql_database = '';

	}

	// Configure MySQL Database Settings
	define( 'DB_USER',      $mysql_username );
	define( 'DB_PASSWORD',  $mysql_password );
	define( 'DB_NAME',      $mysql_database );
	define( 'DB_HOST',      $mysql_hostname );

	define( 'DB_CHARSET', 'utf8' );
	define( 'DB_COLLATE', '' );

	$table_prefix = 'wp_';

	// WordPress Security Keys
	// http://codex.wordpress.org/Editing_wp-config.php#Security_Keys
	define( 'AUTH_KEY',         'put your unique phrase here' );
	define( 'SECURE_AUTH_KEY',  'put your unique phrase here' );
	define( 'LOGGED_IN_KEY',    'put your unique phrase here' );
	define( 'NONCE_KEY',        'put your unique phrase here' );
	define( 'AUTH_SALT',        'put your unique phrase here' );
	define( 'SECURE_AUTH_SALT', 'put your unique phrase here' );
	define( 'LOGGED_IN_SALT',   'put your unique phrase here' );
	define( 'NONCE_SALT',       'put your unique phrase here' );

	// Wordpress Application Options + Settings
	// http://codex.wordpress.org/Editing_wp-config.php
	define( 'WP_HOME',    'http://' . $_SERVER['SERVER_NAME'] );
	define( 'WP_SITEURL', 'http://' . $_SERVER['SERVER_NAME'] );

	define( 'AUTOSAVE_INTERVAL', 300 );
	define( 'WP_POST_REVISIONS', false );

	define( 'WP_CACHE', true );
	define( 'WP_MEMORY_LIMIT', '128M' );

	if ( ! defined( 'ABSPATH' ) ) {
		define( 'ABSPATH', dirname( __FILE__ ) . '/' );
	}

	define( 'ABSPATH', dirname(__FILE__) . '/' );
	require_once( ABSPATH . 'wp-settings.php' );

?>