PHP Config File using Singleton Pattern

The Problem

Today I needed to have configuraion variables available across multiple PHP  scripts / classes,  I didn’t want to pass the array accross files or corrupt the global scope.

The solution

A this simple class that makes configuration varibles available throught out my application.  It uses a singleton pattern so I know there is only one version of the config.  It also implements all the methods to make it behave like an array and an object ( the Countable, ArrayAccess and InteratorAgregate interfaces to be exact).

The Code

Sample Config File:

<?php
    $config = array();
    $config['my_config_value'] = 'its simple';
    /* ... set more configuration variables ... */
    return $config; // must return an array
?>

Initializing the class:

<?php
    /* initailize the class at the beginning of a script */
    require_once('./SimpleConfig.php');
    SimpleConfig::setFile('./config.php');
?>

Somewhere else in your application:

<?php
    $config = SimpleConfig::getInstance();

    /* Just to show that its an instance not an array */
    if ($config instanceof SimpleConfig) {
        echo "It's an object <br />\n";
    } //if

    /* Access as an array */
    echo $config['my_config_value'] ."<br />\n"; // ouputs: its simple

    /* Access as object */
    echo $config->my_config_value ."<br />\n"; // ouputs: its simple
?>

See it in action: demo
Download the files: simple-php-config-file-using-singleton.zip