require

(PHP 4, PHP 5)

require es idéntico a include excepto que en caso de fallo producirá un error fatal de nivel E_COMPILE_ERROR. En otras palabras, éste detiene el script mientras que include sólo emitirá una advertencia (E_WARNING) lo cual permite continuar el script.

Véase la documentación de include para más información.

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User Contributed Notes 23 notes

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15
chris at chrisstockton dot org
6 years ago
Remember, when using require that it is a statement, not a function. It's not necessary to write:
<?php
 
require('somefile.php');
?>

The following:
<?php
require 'somefile.php';
?>

Is preferred, it will prevent your peers from giving you a hard time and a trivial conversation about what require really is.
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2
tjeerd
7 years ago
When using symbolic links with PHP, specify a dotslash './page.php' path to ensure that PHP is looking in the right directory with nested requires:

E.g. when the required actual page1.php contains other require statements to, say page2.php, PHP will search the path that the symbolic link points to, instead of the path where the symbolic link lives. To let PHP find the other page2.php in the path of the symbolic link, a require('./page2.php'); statement will solve the puzzle.
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2
Peter McDonald
6 years ago
re the comment by moazzamk at gmail dot com

As the manual states require and require_once as of PHP 4.02 no longer call the file if the line of code it is on should not be executed.
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2
daniel at nohair dot com
6 years ago
I love php.  But when file can't be included, 'require' or 'require_once' throw fatal error and halt the script, which is almost never desirable on a mission-critical production server.  I think it may be better to use something like the following. 

<?php

if (@include 'plan_A.php') {
   
// Plan A;
} elseif (@include 'plan_B.php') {
   
// Plan B;
} else {
   
// Hope never happens.  If does, then Email the webmaster;
    // Call 911, Medic, Fire, Police, the president;
    // Change hard drive, server, hosting service;
}

?>

Or handle trouble first is you wish

<?php

if (!@include 'plan_A.php') {
   
// Someone has kidnapped/corrupted Plan_A.php;
    // Email the webmaster;
    // Change hard drive, server, hosting service;
} else {
   
// Plan A;
}

?>
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2
gabe at websaviour dot com
7 years ago
If you are experiencing a bug related to using relative paths with include or require, it may be related to a grandparent directory that is executable but not readable.  It will cause __FILE__ to return a relative path instead of the full path which it is supposed to show.  This manifests itself in interesting ways that can be seemingly unrelated.  For instance, I discovered it using the Smarty {debug} command which failed to find its template due to this issue.  Please see the following for more details:

http://bugs.php.net/bug.php?id=34552
http://shiftmanager.net/~kurt/test/
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2
ricardo dot ferro at gmail dot com
5 years ago
Two functions to help:

<?php

function add_include_path ($path)
{
    foreach (
func_get_args() AS $path)
    {
        if (!
file_exists($path) OR (file_exists($path) && filetype($path) !== 'dir'))
        {
           
trigger_error("Include path '{$path}' not exists", E_USER_WARNING);
            continue;
        }
       
       
$paths = explode(PATH_SEPARATOR, get_include_path());
       
        if (
array_search($path, $paths) === false)
           
array_push($paths, $path);
       
       
set_include_path(implode(PATH_SEPARATOR, $paths));
    }
}

function
remove_include_path ($path)
{
    foreach (
func_get_args() AS $path)
    {
       
$paths = explode(PATH_SEPARATOR, get_include_path());
       
        if ((
$k = array_search($path, $paths)) !== false)
            unset(
$paths[$k]);
        else
            continue;
       
        if (!
count($paths))
        {
           
trigger_error("Include path '{$path}' can not be removed because it is the only", E_USER_NOTICE);
            continue;
        }
       
       
set_include_path(implode(PATH_SEPARATOR, $paths));
    }
}

?>
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1
Anonymous
9 years ago
Note when calling any require or include function, that the call will block if the script given as the parameter is excecuting.
Because of this one should be careful when using blocking functions like sleep() in a script which is included by another.
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1
Anonymous
7 years ago
A note that drove me nuts for 2 days!

Be carfull if you have a newline or blank space befor your php tags in the included/required file it will read as html and outputed.

If your running your output through javascript string evaluations which would be sensitive to newlines/white spaces be carfull that the first chars in the file are the php tages eg <?php
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0
duccio at getlocal dot it
5 years ago
In response to some dot user at notarealdomain dot com:

This is because require executes the code "as if" it was code written inside of the function, inheriting everything including the scope. But here there is something even more interesting:

<requiredfile.php>:
<?php

$this
->a.=" is visible also under a require\n";
$b="While the variable b is a local variable of the function\n";
function
FunctionUnderRequire() {
    echo
"But the functions declared inside of a require called from a class function, just as when defined from inside any other function, are always global\n";
}
?>

<mainfile.php>:
<?php

error_reporting
(E_ALL|E_STRICT);

class
UserClass {

    protected
$a;

    public function
UserFunction() {
       
$this->a='The class variable a';
        require
'requiredfile.php';
        echo
$this->a; // "The class variable a  is visible also under a require\n"
       
echo $this->b; // Notice: Undefined property: UserClass::$b
       
echo $b; // "While the variable b is a local variable of the function\n"
       
$this->FunctionUnderRequire(); //Fatal error!
       
FunctionUnderRequire(); // "But the functions..."
   
}
}

$UserClass=new UserClass;
$UserClass->UserFunction();
?>

I'm wondering if there is a method for declaring class public/private/protected functions from inside a require/include...
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0
Inc
7 years ago
I have found a problem when I try to access a php file via require($class_directory)

// # $class_directory contain a long full path and dot into the last folder.
// # $class_directory = "/var/.../app/system/plugintoto_1.0/class_plugintoto_1.0.php";

// dot ('.') and minus ('-') are not accepted in require !
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0
webmaster at netgeekz dot net
8 years ago
I have learnt to manipulate this code into an effecitve and easy to use form. I use it with require_once, but it could be used for require.

require_once($_SERVER['DOCUMENT_ROOT'].'/includes/top.php');

This mainly jumps back to the servers document root and then begins to enter the directories defined until it finds the file. In this case it would go back to the root of the server, or whatever your document root is, and then enter includes. there it would search for the top.php file. Simple to use, yet effective...espcially for people like me who re-use code or move files to different directories. I don't have to fix the includes, because they all work the same way.
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0
dave at davidhbrown dot us
8 years ago
re: danielm at unb dot br...

$_SERVER['DOCUMENT_ROOT'] is very useful, but it is not available with all web servers. Apache has it; IIS doesn't.

I use the following to make my PHP applications work in more situations:
<?php
if (!defined("BASE_PATH")) define('BASE_PATH', isset($_SERVER['DOCUMENT_ROOT']) ? $_SERVER['DOCUMENT_ROOT'] : substr($_SERVER['PATH_TRANSLATED'],0, -1*strlen($_SERVER['SCRIPT_NAME'])));
?>

...but even that gets tripped up by symlinks to different mount points, etc. You could substitute realpath($_SERVER['PATH_TRANSLATED']), but that function has been reported not to work on some (Windows) servers. One could use the PATH_TRANSLATED for both servers, but I figure if Apache is going to tell me exactly what I want to know, I should listen.
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0
Marc
8 years ago
This will sound elementary, but for C++ native programmers, be sure NOT to put a '#' in front of your include statements! The parser will not give you an error, but also will not include the file, making for a tedious debugging process.

In short, USE:
<?php
    
include "yourfile.php";
?>

and DON'T use:
<?php
    
#include "yourfile.php";
?>
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0
richardbrenner(-at- )gmx(-)at
9 years ago
If you use relativ paths in a php script (file A) that can be required by another php script (file B), be aware that the relativ paths in file A will be relativ to the directory, where file B is stored.
You can use the following syntax in file A, to be sure that the paths are relativ to the directory of file A:

<?
require(dirname(__FILE__)."/path/relative/file_to_include.php");
?>

Greetings,
Richard
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-1
scott
6 years ago
If you want to verify that a file can be included or required, the simplest solution I've found is just to check that the file exists.

<?php

   
if(file_exists($pageContentInc)){
        require_once
$pageContentInc;
    }else{
       
$pageContentInc = "common/content_404.inc";
        require_once
$pageContentInc;
    }
?>

Does it really need to be any harder than that?
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-1
moreau dot marc dot web at gmail dot com
2 months ago
Petit script pour résoudre le problème de l'inclusion dans l'inclusion.

A requiert B qui requiert C -> l'on doit normalement faire correspondre le requiere de B en fonction de l'endroit ou se trouve A dans l'arborescence du site. Pas de souci, sauf si l'on est amené à requérir B depuis une autre page, impossible alors de faire appel au C -> cela retourne une erreur "fichier non trouvé".

Voici une solution qui marche sur tout type de configuration:

Dans B:

<?php

chdir
(__DIR__); //Sert à indiquer à PHP le dossier de référence de travail

$file_to_require=realpath('./../../adresse_de_C_relative_par_raport_a_B.php'); //Crée l'adresse absolue de C

require($file_to_require); unset($file_to_require);

?>
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-1
some dot user at notarealdomain dot com
6 years ago
Discovered a bit of weird behavior yesterday involving require() (using PHP 5.2.3).  If you use require() inside a function, the "globals" in the file will be local to the function.  An example of this:

test.php:
<?php
 
function TestFunc()
  {
    require(
'test2.php');
    echo
"<pre>" . print_r($GLOBALS, true) . "</pre>";
  }
?>

test2.php:
<?php
  $MyTestGlobal
= Array();
?>

This happens because require is a statement that _inlines_ the target code - not a function that gets called.

To fix this, use the $GLOBALS superglobal:

test2.php:
<?php
  $GLOBALS
["MyTestGlobal"] = Array();
?>
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-1
bmessenger at 3servicesolution dot com
7 years ago
// Looks like I might have a fix for some on the
// relative path issue.

if (!function_exists('bugFixRequirePath'))
{
    function bugFixRequirePath($newPath)
    {
        $stringPath = dirname(__FILE__);
        if (strstr($stringPath,":")) $stringExplode = "\\";
        else $stringExplode = "/";
       
        $paths = explode($stringExplode,$stringPath);
       
        $newPaths = explode("/",$newPath);
       
        if (count($newPaths) > 0)
        {
            for($i=0;$i<count($newPaths);$i++)
            {
                if ($newPaths[$i] == "..") array_pop($paths);   
            }
           
            for($i=0;$i<count($newPaths);$i++)
            {
                if ($newPaths[$i] == "..") unset($newPaths[$i]);
            }
           
            reset($newPaths);
           
            $stringNewPath = implode($stringExplode,$paths).
                $stringExplode.implode($stringExplode,$newPaths);
           
                return $stringNewPath;
        }
    }   
}

require_once(bugFixRequirePath("../config.php"));
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-1
moazzamk at gmail dot com
6 years ago
require and include read the included files even if they are not executed in the code. You can use eval() to avoid this.

eval('require filename;');

I don't know if it's faster to have the files included the regular way or the eval way though (in other words, I haven't tested their efficiency). It will be great if someone can test which is better.
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-2
hans at ratzinger dot com
7 months ago
Thanks a lot for this information Brian! This drove me nuts for many hours! This is the first information I found in the web that a white page can be caused by a require -> your script will die if the file is not found!!!
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-1
danielm at unb dot br
9 years ago
if you want to include files with an absolut path reference, you can use:

require ($_SERVER["DOCUMENT_ROOT"]."/path/to/file.php");

this way you can organize your files in subdirectories trees.
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-2
Wing
3 years ago
if you want always include, require, open files using some 'root' folder based path you may may put file '.htroot' in 'root' folder and  use this.

while(!file_exists(getcwd()."/.htroot")){chdir('..');}

This code change current dir to dir where '.htroot' file located and everywhere you can use relative to 'root' paths.

Please avoid absent of '.htroot' file.
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-4
pedro dot evangelista at gmail dot com
5 years ago
Be careful when using symbolic links, because require will search the real path of the file and not the path relative to the symbolic link.

Imagine your script A.php resides on directory /a and you create a symbolic link for it on directory /b/c.
So for the code

<?php
echo realpath("../");
?>

you might expect the directory /b, but actually you get the root directory /.

If you need to include the file /b/B.php inside your A.php, you can't use the following

<?php
require "../B.php";
?>

because it will search the root directory, not the /b directory.

Regards.
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