CakePHP 2.x database.php file to switch between database configuration settings based on file existence under app/Config directory

database.php

<?php
// CakePHP 2.x database.php file to switch between database configuration settings based on file existence under app/Config directory

/**
 * This is core configuration file.
 *
 * Use it to configure core behaviour of Cake.
 *
 * PHP 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       app.Config
 * @since         CakePHP(tm) v 0.2.9
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 *
 * Database configuration class.
 * You can specify multiple configurations for production, development and testing.
 *
 * datasource => The name of a supported datasource; valid options are as follows:
 *		Database/Mysql 		- MySQL 4 & 5,
 *		Database/Sqlite		- SQLite (PHP5 only),
 *		Database/Postgres	- PostgreSQL 7 and higher,
 *		Database/Sqlserver	- Microsoft SQL Server 2005 and higher
 *
 * You can add custom database datasources (or override existing datasources) by adding the
 * appropriate file to app/Model/Datasource/Database. Datasources should be named 'MyDatasource.php',
 *
 *
 * persistent => true / false
 * Determines whether or not the database should use a persistent connection
 *
 * host =>
 * the host you connect to the database. To add a socket or port number, use 'port' => #
 *
 * prefix =>
 * Uses the given prefix for all the tables in this database. This setting can be overridden
 * on a per-table basis with the Model::$tablePrefix property.
 *
 * schema =>
 * For Postgres/Sqlserver specifies which schema you would like to use the tables in. Postgres defaults to 'public'. For Sqlserver, it defaults to empty and use
 * the connected user's default schema (typically 'dbo').
 *
 * encoding =>
 * For MySQL, Postgres specifies the character encoding to use when connecting to the
 * database. Uses database default not specified.
 *
 * unix_socket =>
 * For MySQL to connect via socket specify the `unix_socket` parameter instead of `host` and `port`
 */
  
  
class DATABASE_CONFIG {
    public $default = null;
    
    public $dev = array(
        //put database config here
    );

    public $test = array(
        //put database config here
    );
    
    public $prod = array(
        //put database config here
    );
    
    public function __construct(){
        App::uses('Folder', 'Utility');
        
        //if file named USE_DATABASE_CONFIG_name exists, use DATABASE_CONFIG.name as default config
        //if multiple USE_DATABASE_CONFIG_* files found, use the first one.
        $dir_path = ROOT . DS . APP_DIR . DS . 'Config' . DS;
        $dir = new Folder($dir_path);
        $f = $dir->find('USE_DATABASE_CONFIG_.*', true);
        if (count($f)<=0) {
            //using default(dev) setting if USE_DATABASE_CONFIG_* is not found.
            $this->default = $this->dev;
            return;
        } else {
            //using default(dev) setting if USE_DATABASE_CONFIG_* is not found.
            //fetch config name
            ereg('USE_DATABASE_CONFIG_(.*)', $f[0], $ret);
            $config_name = $ret[1];
            if (isset($this->{$config_name})) {
                $this->default = $this->{$config_name};
            } else {
                //use default(dev) configuration if accoumpanied configuration is not found
                $this->default = $this->dev;
            }
            return;
        } 
    }
}