[TUTORIAL] Defining Paths in PHP

[RageD]

As many of you can probably see I haven't been around the forum in around a month or so. Been kind of busy upon other things and have been getting a lot of questions about doing different things in PHP. So this may be the first in possibly a series of tutorials to get all questions answered :p

In this tutorial I'll explain "define" pretty much and how to get it to define something like "ROOT_PATH". (not being so much a variable)

Unless you feel like defining everything in every file, I suggest the best way to define is make a file called something like "init.php". That's what I'll be using for the example.

init.php

<?php
/**
 * init.php for "Defining Paths in PHP" Tutorial by RageD
 * (C) 2008 RageD
 *
 */

/**
 * This first one is simply for security. Accessing functions
 * without proper access is bad :(
 *
 */
define("SITE_SCRIPT", true);

/**
 * Here we'll define the root path. Make sure that this file
 * is in the ROOT directory! :)
 *
 */
define("ROOT_PATH", dirname(__FILE__));

/**
 * And finally.. Our includes. In this example it will be the
 * "includes" directory.
 *
 */
define("INC_PATH", ROOT_PATH . '/includes');

/**
 * Final step... Make sure that this worked properly
 * :)
 *
 */
define("INIT_DONE", true);
?>

Now make a directory call includes and then a file called function.php.

includes/function.php

<?php
/**
 * includes/function.php for "Defining Paths in PHP" Tutorial by RageD
 * (C) 2008 RageD
 *
 */
// This is where that security definition comes into play :)
if(!defined("SITE_SCRIPT"))
{
     print("Unauthorized Access!");
     exit;
}

// Next, just a simple class and function example.
class Test
{
	/**
	 * Constructor :)
	 *
	 */
	function __construct()
	{
		$this->text = "Hello World!<br />This script actually does work! :D";
	}

	/**
	 * Basically just print $this->text
	 *
	 */
	function hello()
	{
		echo($this->text);
		exit;
	}
}
?>

Now finally just put this in an index.php or something so you can view it all done right

index.php

<?php
/**
 * includes/function.php for "Defining Paths in PHP" Tutorial by RageD
 * (C) 2008 RageD
 *
 */

// Place this file in the ROOT directory with init.php
require_once("init.php");

// Check if it worked properly or not
if(!defined("INIT_DONE"))
{
	echo("Doh! Houston, we have a problem. We did not initiate correctly!");
	exit;
}

// Get our function :D
require_once(INC_PATH . "/function.php");

$test = new Test; // Define our class so we can perform the function.

$test->hello(); // Run the function!
?>

I've even attached a copy of the script for anyone interested.

Any questions, let me know

-RageD

 

[Keral_Patel]

Great explanation.

Can also be used somewhere where we define database settings

Thanks for writing it.