Building a basic input class - PHP

For this particular project, the input class that I'm going to build in the following lines will be basically a wrapper or proxy for accessing variables within the $_GET and $_POST PHP superblobal arrays. Its driving logic will be inspired partially by the input class provided by the Kohana framework, so let me give the corresponding credits to its development team.  

Naturally, in production environments, this class should be improved to offer more thorough protection against XSS and SQL injection attacks. Having explained that, please study the definition of the class, which is as follows:

class Input

{

                private static $instance = NULL;

                // get Singleton instance of Input class

                public static function getInstance()

                {

                                if (self::$instance === NULL)

                                {

                                                self::$instance = new self;

                                }

                                return self::$instance;

                }

                // get $_GET variable

                public static function get($var = NULL)

                {

                                if (!isset($_GET[$var]))

                                {

                                                return $var;

                                }

                                return mysql_escape_string(trim($_GET[$var]));

                }

                // get $_POST variable

                public static function post($var = NULL)

                {

                                if (!isset($_POST[$var]))

                                {

                                                return $var;

                                }

                                return mysql_escape_string(trim($_POST[$var]));

                }

}// End Input class

As I said a moment ago, the brand new "Input" class implements a basic API that allows you to access GET and POST data in a truly simple fashion. Also, notice that this class defines a static "getInstance()" method that returns a Singleton instance of it, which can be used as a single access point to the class across the whole framework. However, in a typical situation this class should be used only statically.

Now that you hopefully understood how the input class does its thing, I'm going to show you the updated source code of the framework, logically including the file that contains this last class.

This will be done in the last segment of this tutorial, so simply click on the link below and keep reading.