PHP Global Variable Alternative

Introduction

The custom class below is an alternative to using PHP global variables. It is safe to use this class to control globals being defined once for the application. You can also access the globals within classes and methods without the global identifier.

Background

I created this custom class, because I needed a way to store my globals without being changed by third party code. It achieves this by using PHP Late Static Bindings with self and static declarations.

Custom Class for Handling Globals

if(!class_exists('globals'))
{
    // Handles all the globals for the page.
    class globals 
    {
        private static $vars = array();

        // Sets the global one time.
        public static function set($_name, $_value) 
        {
            if(array_key_exists($_name, self::$vars))
            {
                throw new Exception('globals::set("' . $_name . '") - Argument already exists and cannot be redefined!');
            }
            else
            {
                self::$vars[$_name] = $_value;
            }
        }

        // Get the global to use.
        public static function get($_name) 
        {
            if(array_key_exists($_name, self::$vars))
            {
                return self::$vars[$_name];
            }
            else
            {
                throw new Exception('globals::get("' . $_name . '") - Argument does not exist in globals!');
            }
        }
    }
}

How to Define Global

Here is an example of how to define a simple and complex global.

PHP

// Simple Definition
globals::set('website','codeproject');

// Complex Definition with Array
globals::set('SERVER', array(
    'REMOTE_ADDR' => filter_input(INPUT_SERVER, 'REMOTE_ADDR'),
    'PHP_SELF' => filter_input(INPUT_SERVER, 'PHP_SELF', FILTER_SANITIZE_URL)
));

How to Use on Line, Method or Class

The below examples will show you how to use it in your code.

// Using Outside Class
echo globals::get('website');

// Using in Method
function getwebsite()
{
  echo globals::get('website');
}

// Using in Class
class websites
{
  public function getwebsite()
  {
    return globals::get('website');
  }
}

$websites = new websites();
echo $websites->getwebsite();

// Using Global Array Definition
$SERVER = globals::get('SERVER');
echo $SERVER['PHP_SELF'];

// OR Directly in PHP 5.4
echo globals::get('SERVER')['PHP_SELF'];

Global Variable Redefinition

Once a global variable has been defined, it cannot be changed. So if you define an array, it has to be all at once. The example below shows this.

// Define Once
globals::set('website','codeproject');

// Get should be codeproject 
echo globals::get('website');

// Define Twice
globals::set('website','google');

// Get should still be codeproject
echo globals::get('website');

Conclusion

I hope this code saves you development time. :)