How to set root folder for PHP include files

dirname(__FILE__) and __DIR__ both same and __DIR__ comes with PHP 5.3

These are used in order to indicate that the "path of the file where they called".

URL: http://localhost/test/a.phpDIR: --NIX     /var/www/test/a.php     --WIN     D:\lamp\www\test\a.php// a.php's inside<?phpecho __DIR__;

Gives you this on linux: /var/www/test

So, if you need a config parameter in all your project, just define it in your config.php and use it where you want both the file name that will be included.

./  config.php  index.php  header.php  footer.php  /lib    foo.php  /tmp    bar.php

./config.phpdefine('ROOT', __DIR__ .'/');

./index.php include_once(ROOT .'header.php'); ... include_once(ROOT .'footer.php');

i.e, using it in tmp dir

./tmp/bar.php include_once(ROOT .'lib/foo.php');

UPDATE

// config.php<?phpdefine("ROOT", __DIR__ ."/");

So, we use this for index.php to include banner.php and banner.php is waiting in ./banners/banner.php;

// index.php and the very first line!<?phpinclude_once("config.php");?>// some html stuff// ...<?php include_once(ROOT ."banners/banner.php"); ?>// some more html stuff// ...

So, you should include config.php first to where you need it.

I think, this is basic as far as needed...

UPDATE

So your problem is not PHP include system, but question, anyway... :)

If your image path is changing (so not fixed), you can do like this;

// config.phpdefine("ROOT", __DIR__ ."/");define("HTTP", ($_SERVER["SERVER_NAME"] == "localhost")   ? "http://localhost/your_work_folder/"   : "http://your_site_name.com/");// banner.php<img src="<?php print HTTP; ?>images/banner.gif">

I normally set up what you mentioned, a config.php in an include directory, and have the following line in it: define('BASE_PATH', str_replace('/include', '', dirname(__FILE__))); ("/include should be whatever directory your config.php file is in, if you have it in the root directory, you can just use define('BASE_PATH', dirname(__FILE__));). When I want to include any other file after that, I use include_once(BASE_PATH . '/directory/file.php');.

note: this concept is not original to me by any means.

There is a function called getcwd() which will return the current working folder. If you call this at the very beginning of your script, you can store this, usually into a constant with define().

define('PROJECT_ROOT', getcwd());