relative path in require_once doesn't work

问题

I have the following structure

otsg
 > class
   > authentication.php
   > database.php
   > user.php
 > include
   > config.inc.php
   > encryption.php
   > include.php
   > session.php
 > index.php
 > registration.php

include.php file has the following

ini_set(\'display_errors\', 1);
error_reporting(E_ALL);

ini_set(\'include_path\',ini_get(\'include_path\').\':/Applications/MAMP/htdocs/otsg/:\');
require_once \'config.inc.php\';
require_once \'../class/database.php\';
require_once \'../class/user.php\';
require_once \'encryption.php\';
require_once \'session.php\';
require_once \'../class/authentication.php\';

and in the index.php page I had included

require_once \'include/include.php\';

When I open the page index.php I get the following warning and fatal error. I don\'t understand what causes this error. When I gave the absolute path it works. But absolute path is not a good idea i believe.

Warning: require_once(../class/database.php) [function.require-once]: failed to open stream: No such file or directory in /Applications/MAMP/htdocs/otsg/include/include.php on line 9

Fatal error: require_once() [function.require]: Failed opening required \'../class/database.php\' (include_path=\'.:/Applications/MAMP/bin/php5.3/lib/php:/Applications/MAMP/htdocs/otsg/include/:\') in /Applications/MAMP/htdocs/otsg/include/include.php on line 9

Thanks in advance

回答1:

Use

__DIR__

to get the current path of the script and this should fix your problem.

So:

require_once(__DIR__.'/../class/user.php');

This will prevent cases where you can run a PHP script from a different folder and therefore the relatives paths will not work.

Edit: slash problem fixed

回答2:

for php version 5.2.17 __DIR__ will not work it will only works with php 5.3

But for older version of php dirname(__FILE__) perfectly

For example write like this

require_once dirname(__FILE__) . '/db_config.php';

回答3:

In my case it doesn't work, even with __DIR__ or getcwd() it keeps picking the wrong path, I solved by defining a costant in every file I need with the absolute base path of the project:

if(!defined('THISBASEPATH')){ define('THISBASEPATH', '/mypath/'); }
require_once THISBASEPATH.'cache/crud.php';
/*every other require_once you need*/

I have MAMP with php 5.4.10 and my folder hierarchy is basilar:

q.php 
w.php 
e.php 
r.php 
cache/a.php 
cache/b.php 
setting/a.php 
setting/b.php

....

回答4:

I just came across this same problem, where it was all working fine, up until the point I had an includes within another includes.

require_once '../script/pdocrud.php';  //This worked fine up until I had an includes within another includes, then I got this error:
Fatal error: require_once() [function.require]: Failed opening required '../script/pdocrud.php' (include_path='.:/opt/php52/lib/php')

Solution 1. (undesired hardcoding of my public html folder name, but it works):

require_once $_SERVER["DOCUMENT_ROOT"] . '/orders.simplystyles.com/script/pdocrud.php';

Solution 2. (undesired comment above about DIR only working since php 5.3, but it works):

require_once __DIR__. '/../script/pdocrud.php';

Solution 3. (I can't see any downsides, and it works perfectly in my php 5.3):

require_once dirname(__FILE__). '/../script/pdocrud.php';

来源：https://stackoverflow.com/questions/5371828/relative-path-in-require-once-doesnt-work