rename> <realpath_cache_size
Last updated: Fri, 03 Feb 2012

realpath

(PHP 4, PHP 5)

realpath — Retorna o path absoluto canonicalizado

Descrição

string realpath ( string $path )

realpath() expande todos os links simbólicos e resolve referências para '/./', '/../' e extra caracteres '/' na entrada pelo path, e retorna o path absoluto canonicalizado.

Parâmetros

path

O caminho a ser verificado.

Valor Retornado

Retorna o path absoluto em sucesso. O path resultante não conterá nenhum link simbólico ou componentes '/./' e '/../'.

realpath() retorna FALSE em caso de falha, por exemplo, se o caminho não existir. Em sistemas BSD realpath() não falha se somente o último componente do path não existe, quando em outro sistema irá retornar FALSE.

Exemplos

Exemplo #1 Exemplo da realpath()

<?php
chdir('/var/www/');
echo realpath('./../../etc/passwd');
?>

O exemplo acima irá imprimir:

/etc/passwd

Exemplo #2 realpath() em Windows

Em Windows, realpath() modificará o estilo unix de diretórios para o estilo Windows.

<?php
echo realpath('/windows/system32');
?>

O exemplo acima irá imprimir:

C:\WINDOWS\System32

Veja Também

  • basename() - Retorna a parte nome do arquivo do caminho/path
  • dirname() - Retorna o componente diretório de um caminho/path
  • pathinfo() - Retorna informações sobre um caminho de arquivo



rename> <realpath_cache_size
Last updated: Fri, 03 Feb 2012
 
User Contributed Notes
realpath
kai dot grossjohann at gmx dot net
08-Feb-2012 02:51
@dbas: junction.exe creates hard links, not symlinks.  And there is no concept of a "real" file name with hard links.
flaviu at silkweb dot ro
03-Feb-2012 09:35
$put = realpath(dirname(__DIR__).'/../../../').'/'; - return the path on localserver and on webserver while
$put = realpath(dirname(__DIR__).'../../../').'/'; returns the path only on localserver. On webserver it returns false (file does not exist)
dbags
08-Jan-2012 11:37
If using Windows junction.exe to create a symlink, it seems impossible to get the real path to the file. Even __FILE__ contains the symlinked path, not the actual path of the file.
spam at klickagent dot ch
21-Nov-2011 06:42
realpath() function for relative paths:

$relativePath = '../gallery/index/../../advent11/app/';

$pattern = '/\w+\/\.\.\//';
while(preg_match($pattern,$relativePath)){
    $relativePath = preg_replace($pattern, '', $relativePath);
}

output: '../advent11/app/'
php at keith tyler dot com
18-Oct-2011 10:15
Note that under Windows, a slash-rooted path will resolve on the local drive, and *not* necessarily C:\.

For example:

M:\>php -r "print realpath('/AUTOEXEC.BAT');"
[prints nothing, because there is no M:\AUTOEXEC.BAT]

But:

M:\>C:
C:\>php -r "print realpath('/AUTOEXEC.BAT');"
C:\AUTOEXEC.BAT

Same script, different response depending on current drive.

I'm inclined to argue that this function *should* use the value of %SystemDrive% as the "slash root" base.
imagiro
21-Sep-2011 11:20
Here is a small and handy method to calculate the relative path from $from to $to. Note: On Windows it does not work when $from and $to are on different drives.

<?php
function relativePath($from, $to, $ps = DIRECTORY_SEPARATOR)
{
  $arFrom = explode($ps, rtrim($from, $ps));
  $arTo = explode($ps, rtrim($to, $ps));
  while(count($arFrom) && count($arTo) && ($arFrom[0] == $arTo[0]))
  {
    array_shift($arFrom);
    array_shift($arTo);
  }
  return str_pad("", count($arFrom) * 3, '..'.$ps).implode($ps, $arTo);
}
?>
netmosfera at gmail dot com
13-Apr-2011 06:55
please note that realpath is a performance killer

on my sys listing 100 files with realpath takes 0.2 sec (core2quad 6600 x64 4gbddr2)

in most cases, its better to use getcwd() instead and work with dirname() to resolve ".."
Jrg Wagner
10-Jun-2010 09:35
Please be aware that this function does NOT always strip a trailing slash!:

LINUX (tested with PHP 5.2.11):
---
realpath('.')
: string = "/myhttpdfolder"
realpath('./')
: string = "/myhttpdfolder"
realpath('fileadmin')
: string = "/myhttpdfolder/fileadmin"
realpath('fileadmin/')
: string = "/myhttpdfolder/fileadmin"

WINDOWS (tested with PHP 5.2.5):
---
realpath('.')
: string = "C:\\myhttpdfolder"
realpath('./')
: string = "C:\\myhttpdfolder\\"
realpath('fileadmin')
: string = "C:\\myhttpdfolder\\fileadmin"
realpath('fileadmin/')
: string = "C:\\myhttpdfolder\\fileadmin\\"
jpic
13-May-2010 09:04
There is no native function that does the opposite.

Pure-php implementation:

<?php
function getRelativePath( $path, $compareTo ) {
        // clean arguments by removing trailing and prefixing slashes
        if ( substr( $path, -1 ) == '/' ) {
            $path = substr( $path, 0, -1 );
        }
        if ( substr( $path, 0, 1 ) == '/' ) {
            $path = substr( $path, 1 );
        }

        if ( substr( $compareTo, -1 ) == '/' ) {
            $compareTo = substr( $compareTo, 0, -1 );
        }
        if ( substr( $compareTo, 0, 1 ) == '/' ) {
            $compareTo = substr( $compareTo, 1 );
        }

        // simple case: $compareTo is in $path
        if ( strpos( $path, $compareTo ) === 0 ) {
            $offset = strlen( $compareTo ) + 1;
            return substr( $path, $offset );
        }

        $relative  = array(  );
        $pathParts = explode( '/', $path );
        $compareToParts = explode( '/', $compareTo );

        foreach( $compareToParts as $index => $part ) {
            if ( isset( $pathParts[$index] ) && $pathParts[$index] == $part ) {
                continue;
            }

            $relative[] = '..';
        }

        foreach( $pathParts as $index => $part ) {
            if ( isset( $compareToParts[$index] ) && $compareToParts[$index] == $part ) {
                continue;
            }

            $relative[] = $part;
        }

        return implode( '/', $relative );
    }
?>

Some tests forr phpunit:

<?php
    static public function getRelativePathProvider(  )  {
        return array(
            array(
                '/srv/foo/bar',
                '/srv',
                'foo/bar',
            ),
            array(
                '/srv/foo/bar',
                '/srv/',
                'foo/bar',
            ),
            array(
                '/srv/foo/bar/',
                '/srv',
                'foo/bar',
            ),
            array(
                '/srv/foo/bar/',
                '/srv/',
                'foo/bar',
            ),
            array(
                '/srv/foo/bar',
                '/srv/test',
                '../foo/bar',
            ),
            array(
                '/srv/foo/bar',
                '/srv/test/fool',
                '../../foo/bar',
            ),
            array(
                '/srv/mad/xp/mad/model/static/css/uni-form.css',
                '/srv/mad/xp/liria/',
                '../mad/model/static/css/uni-form.css',
            ),
        );
    }

    /**
     * @dataProvider getRelativePathProvider
     */
    public function testGetRelativePath( $path, $compareTo, $expected ) {
        $result = getRelativePath( $path, $compareTo );
        $this->assertEquals( $expected, $result );
    }
?>
roman dot vasicek at email dot cz
03-Dec-2009 07:01
You may want to change script behavior depending on the way how its code is invoked (included by another script / called directly). Following code do the job
<?php
if (realpath(__FILE__) == realpath($_SERVER['SCRIPT_FILENAME'])) {
  // called directly
  ...
} else {
  // included
  ...
}
?>
hrcerqueira at gmail dot com
01-Dec-2009 02:08
if you just need to resolve a path that is not on your system, or you don't want to chdir to it, a simple regular expression can do the trick:

<?php

$p = '/cool/yeah/../zzz';

$p = preg_replace('/\w+\/\.\.\//', '', $p);

echo $p; //outputs /cool/zzz

?>
cory dot mawhorter gmail.com
28-Jul-2009 09:36
<?php

// fixes windows paths...
// (windows accepts forward slashes and backwards slashes, so why does PHP use backwards?
function fix_path($path) {
    return str_replace('\\','/',$path);
}

// takes two absolute paths and determines if one is a subdirectory of the other
// it doesn't care if it is an immediate child or 10 subdirectories deep...
// use absolute paths for both for best results
function is_child($parent, $child) {
    if(false !== ($parent = realpath($parent))) {
        $parent = fix_path($parent);
        if(false !== ($child = realpath($child))) {
            $child = fix_path($child);
            if(substr($child, 0, strlen($parent)) == $parent)
                return true;
        }
    }
   
    return false;
}

?>
orssey
16-Apr-2009 10:57
<?php

Class RealPath
{
    private $ServerPath;
    private $ScriptPath;
    private $AddSlashEnd;

    function __construct()
    {
        $this->AddSlashEnd = "";
       
        $this->ServerPath = $_SERVER['DOCUMENT_ROOT'];
        $this->ScriptPath = substr(dirname($_SERVER['SCRIPT_FILENAME']), strlen($this->ServerPath));
    }
   
    private function Server($adress)
    {
        $ThisPath = @realpath($adress);
        $ThisPathLength = strlen($ThisPath);
   
        return substr($ThisPath, strlen($this->ServerPath), $ThisPathLength);
    }
   
    public function Absolute($adress)
    {
        return $_SERVER['SERVER_NAME'] . $this->Server($adress) . $this->AddSlashEnd;
    }
   
    public function RelativeServer($adress)
    {
        return $this->Server($adress) . $this->AddSlashEnd;
    }

    public function RelativeScript($adress)
    {
        $ScriptExplode = explode("/", $this->ScriptPath);
        $ServerExplode = explode("/", $this->Server($adress));
       
        $TmpCount = $ScriptCount = count($ScriptExplode);
        $ServerCount = count($ServerExplode);
       
        $ReturnPath = "";
       
        for($i = 1; $i < $TmpCount; $i++)
        {
            if($ScriptExplode[$i] == $ServerExplode[$i])
                --$ScriptCount;
            else
                break;
        }
       
        for($i = 1; $i < $ScriptCount; $i++)
            $ReturnPath .= "/..";

        for($i = $TmpCount - $ScriptCount + 1; $i < $ServerCount; $i++)
            $ReturnPath .= "/" . $ServerExplode[$i];
       
        return $ReturnPath . $this->AddSlashEnd;
    }

    public function AddSlash($value)
    {
        if(is_bool($value))
        {
            $this->AddSlashEnd = ($value)? "/" : "";
            return true;
        }
        else
            return false;
    }
   
}

example:

$ObjectPath = new RealPath;
$ObjectPath->RelativeScript("../a/b../c/d/f../g../h");
info[at]adico.co.il
15-Feb-2009 11:13
for those who want to start realpath on windows platform and looking for example.

OR

for those who want to run zend framework on windows platform using the quick start guide

<?php
define( "_CUR_OS", substr( php_uname( ), 0, 7 ) == "Windows" ? "Win" : "_Nix" );

function checkCurrentOS( $_OS )
{
    if ( strcmp( $_OS, _CUR_OS ) == 0 ) {
        return true;
    }
    return false;
}

// public/index.php
//
// Step 1: APPLICATION_PATH is a constant pointing to our
// application/subdirectory. We use this to add our "library" directory
// to the include_path, so that PHP can find our Zend Framework classes.

if ( checkCurrentOS( "Win" ) ) {
    $mappath = '/' . str_replace( "\\", "/", str_replace( "C:\\","", dirname(__FILE__) ) );
}
else {
    $mappath = dirname(__FILE__);
}

define('APPLICATION_PATH', realpath(  $mappath . '/../_privateadico/application/') );
set_include_path(
    APPLICATION_PATH . '/../library'
    . PATH_SEPARATOR . get_include_path()
);
?>

I took the index.php for zend which is was written for unix and ported it to windows.

The porting problem was with realpath function not understanding dirname(__FILE__) syntex on windows
Isaac Z. Schlueter i at foohack dot com
27-Aug-2008 04:02
If you need to resolve a url against a base url, as the browser does with anchor tags, then realpath won't help, because it's not on your file system.

This function does that:

<?php
function resolve_href ($base, $href) {
     
    // href="" ==> current url.
    if (!$href) {
        return $base;
    }

    // href="http://..." ==> href isn't relative
    $rel_parsed = parse_url($href);
    if (array_key_exists('scheme', $rel_parsed)) {
        return $href;
    }

    // add an extra character so that, if it ends in a /, we don't lose the last piece.
    $base_parsed = parse_url("$base ");
    // if it's just server.com and no path, then put a / there.
    if (!array_key_exists('path', $base_parsed)) {
        $base_parsed = parse_url("$base/ ");
    }

    // href="/ ==> throw away current path.
    if ($href{0} === "/") {
        $path = $href;
    } else {
        $path = dirname($base_parsed['path']) . "/$href";
    }

    // bla/./bloo ==> bla/bloo
    $path = preg_replace('~/\./~', '/', $path);

    // resolve /../
    // loop through all the parts, popping whenever there's a .., pushing otherwise.
        $parts = array();
        foreach (
            explode('/', preg_replace('~/+~', '/', $path)) as $part
        ) if ($part === "..") {
            array_pop($parts);
        } elseif ($part!="") {
            $parts[] = $part;
        }

    return (
        (array_key_exists('scheme', $base_parsed)) ?
            $base_parsed['scheme'] . '://' . $base_parsed['host'] : ""
    ) . "/" . implode("/", $parts);

}
?>

[EDIT BY danbrown AT php DOT net:  Code contains a bugfix supplied by (Zhenya DOT Morozov AT gmail DOT com) on 23-JAN-09, to address the following issue:
'If your path contains "0" (or any "false" string) directory name, the function removes that directory from the path.']
Sven Arduwie
23-Jun-2008 12:43
Because realpath() does not work on files that do not
exist, I wrote a function that does.
It replaces (consecutive) occurences of / and \\ with
whatever is in DIRECTORY_SEPARATOR, and processes /. and /.. fine.
Paths returned by get_absolute_path() contain no
(back)slash at position 0 (beginning of the string) or
position -1 (ending)
<?php
    function get_absolute_path($path) {
        $path = str_replace(array('/', '\\'), DIRECTORY_SEPARATOR, $path);
        $parts = array_filter(explode(DIRECTORY_SEPARATOR, $path), 'strlen');
        $absolutes = array();
        foreach ($parts as $part) {
            if ('.' == $part) continue;
            if ('..' == $part) {
                array_pop($absolutes);
            } else {
                $absolutes[] = $part;
            }
        }
        return implode(DIRECTORY_SEPARATOR, $absolutes);
    }
?>

A test:
<?php
    var_dump(get_absolute_path('this/is/../a/./test/.///is'));
?>
Returns: string(14) "this/a/test/is"

As you can so, it also produces Yoda-speak. :)
waldemar dot axdorph at gmail dot com
08-Jun-2008 05:49
I made this function so that I could see if a user was trying to go above the current directory.

My top dir:
/var/www/dir/

User wanted
/var/www/

This comes in handy when you're making a php explorer/filemanager and you want your files in the directory above to be private.

Here it is

<?php
//usage
//$dir is the dir you are in
//$dir_top is the highest dir allowed.

//example
/*
if(above_dir('../', '/var/www/filemgr'))
    die('Not allowed. Please stick to your directories');
*/
function above_dir($dir, $dir_top){
    if($dir == $dir_top)
        return false;
   
    $dir = realpath($dir);
    $dir_top = realpath($dir_top);
   
    $dir = count(explode('/', $dir));
    $dir_top = count(explode('/', $dir_top));
   
    if($dir <= $dir_top){
        return true;
    }else{
        return false;
    }
}

?>
rlee at excel dot com
24-Apr-2008 12:21
Some users will notice that PHP applications malfunction when they upgrade to PHP 5.2.4 (included in Ubuntu 8.04 LTS) because realpath returns true for files that don't exist.

This is due to the inclusion of the Hardened-PHP Project's Suhosin Patch in many distributions by default. This patch replaces PHPs realpath function with the BSD implementation, which ignores the last path component.

The workaround is to use the file_exists function to verify that the file exists before using realpath to get its real path string.

e.g: instead of:

<?php

if (realpath($path)) {
    $path = realpath($path);
} else {
    throw new Exception('Path not found!');
}
 
?>

Do this:

<?php

if (file_exists($path)) {
    $path = realpath($path);
} else {
    throw new Exception('Path not found!');
}
 
?>

See http://www.hardened-php.net/suhosin/a_feature_list:realpath.html
131 dot php at cloudyks dot org
19-Mar-2008 02:34
<?php
//rp like, working with absolute/relative path & a little bit shorter :p

function rp($path) {
    $out=array();
    foreach(explode('/', $path) as $i=>$fold){
        if ($fold=='' || $fold=='.') continue;
        if ($fold=='..' && $i>0 && end($out)!='..') array_pop($out);
    else $out[]= $fold;
    } return ($path{0}=='/'?'/':'').join('/', $out);
}
?>
alex at bartl dot net
03-Oct-2007 05:25
Sometimes it is helpful to check for the existance of a file
which might be found by using the include_path like in

<?php
include("file_from_include_path.php");
?>

A simple function iterates the include_path and tries all
possibilites, returns translated_local_path on success or false
if not found.

<?php
function mappath($path_to_translate){
  $IncludePath=explode(PATH_SEPARATOR,get_include_path());
  foreach($IncludePath as $prefix){
    if(substr($prefix,-1)==DIRECTORY_SEPARATOR)
      $prefix=substr($prefix,0,-1);
    $try_path=sprintf("%s%s%s"
      ,$prefix,DIRECTORY_SEPARATOR,$path_to_translate);
    if(file_exists($try_path))return($try_path);
  }
  return false;
}
?>
alban dot lopez+php dot net at gmail dot com
21-Sep-2007 09:15
Here's a little function to return the shortest relative path between dest folder and current folder (you can be replace $_SERVER['PHP_SEFL'] by your variable folder) :

<?php
// if you run in /var/www/

echo UnRealPath ('./'); // return "./"
echo UnRealPath ('./ajax-browser/AJAX-B/scripts/'); // return "./ajax-browser/AJAX-B/scripts/"
echo UnRealPath ('/var/'); // return "./../"
echo UnRealPath ('/opt/picasa/wine/'); // return "./../../opt/picasa/wine/"

function UnRealPath ($dest)
{
    $Ahere = explode ('/', realpath($_SERVER['PHP_SEFL']));
    $Adest = explode ('/', realpath($dest));
    $result = '.'; // le chemin retouné dois forcement commancé par ./   c'est le but
    while (implode ('/', $Adest) != implode ('/', $Ahere))// && count ($Adest)>0 && count($Ahere)>0 )
    {
        if (count($Ahere)>count($Adest))
        {
            array_pop($Ahere);
            $result .= '/..';
        }
        else
        {
            array_pop($Adest);
        }
    }
    return str_replace('//', '/', $result.str_replace(implode ('/', $Adest), '', realpath($dest)).(@is_dir(realpath($dest))?'/':''));
}
?>
viaujoc at videotron dot ca
20-Aug-2007 07:50
Beware that the use of a NULL value for the $path argument will give different results depending on the platform:

On Windows, realpath(null) will return the current path (same as realpath(".")).

On Linux (tested on Kernel 2.6) it will return FALSE.
Santosh Patnaik
19-Aug-2007 11:52
Given real paths of two files, this function finds the relative path of one ($dest) with respect to the other ($root).

<?php
echo rel_path('a/b/c', 'd/e'); // './../../a/b/c'
echo rel_path('a/b/c', 'a/b/c/d/e'); // './../..'
echo rel_path('a/b/c/d/e', 'a/b/c'); // './d/e'

function rel_path($dest, $root = '', $dir_sep = '/')
{
 $root = explode($dir_sep, $root);
 $dest = explode($dir_sep, $dest);
 $path = '.';
 $fix = '';
 $diff = 0;
 for($i = -1; ++$i < max(($rC = count($root)), ($dC = count($dest)));)
 {
  if(isset($root[$i]) and isset($dest[$i]))
  {
   if($diff)
   {
    $path .= $dir_sep. '..';
    $fix .= $dir_sep. $dest[$i];
    continue;
   }
   if($root[$i] != $dest[$i])
   {
    $diff = 1;
    $path .= $dir_sep. '..';
    $fix .= $dir_sep. $dest[$i];
    continue;
   }
  }
  elseif(!isset($root[$i]) and isset($dest[$i]))
  {
   for($j = $i-1; ++$j < $dC;)
   {
    $fix .= $dir_sep. $dest[$j];
   }
   break;
  }
  elseif(isset($root[$i]) and !isset($dest[$i]))
  {
   for($j = $i-1; ++$j < $rC;)
   {
    $fix = $dir_sep. '..'. $fix;
   }
   break;
  }
 }
  return $path. $fix;
}
?>
berglov1 at hotmail dot com
24-Jul-2007 04:22
There might be other solutions like mine in here,
but here is one more.

This function converts Virtual Paths into Relative Paths.
I needed that at one time, and I did'nt have much luck finding a solution amongst the PHP Functions in the manual.

<?php
function GetPath($RedPath) {

  if(substr($RedPath, 0, 1) == "/") {
    $SysPath = dirname($_SERVER['PHP_SELF']);

    if(substr($RedPath, -1) == "/") $RedPath = substr($RedPath, 0, -1);

    if(strlen($SysPath) == 1)
      return ".".$RedPath;
    elseif(strcmp($SysPath,$RedPath) == 0)
      return "./"; 

    else {
      $s_tmp = split("/", $SysPath);
      $r_tmp = split("/", $RedPath);

      while(($r_tmp[$i] == $s_tmp[$i]) && $i < 10)
        $i++;

      $t_RedPath = end(split("/", $RedPath, ($i+1))); 

      if($i == count($s_tmp))
        return "./".$t_RedPath;
      else
        return str_repeat("../", count($s_tmp)-$i).$t_RedPath;
    }
  }
  else
    return $RedPath;

}
?>
julabz at laposte dot net
16-Jul-2007 08:49
Here's a little function to return the relative path between two urls:

<?php

    function get_relative_path($start_dir, $final_dir){
        //
        $firstPathParts = explode(DIRECTORY_SEPARATOR, $start_dir);
        $secondPathParts = explode(DIRECTORY_SEPARATOR, $final_dir);
        //
        $sameCounter = 0;
        for($i = 0; $i < min( count($firstPathParts), count($secondPathParts) ); $i++) {
            if( strtolower($firstPathParts[$i]) !== strtolower($secondPathParts[$i]) ) {
                break;
            }
            $sameCounter++;
        }
        if( $sameCounter == 0 ) {
            return $final_dir;
        }
        //
        $newPath = '';
        for($i = $sameCounter; $i < count($firstPathParts); $i++) {
            if( $i > $sameCounter ) {
                $newPath .= DIRECTORY_SEPARATOR;
            }
            $newPath .= "..";
        }
        if( count($newPath) == 0 ) {
            $newPath = ".";
        }
        for($i = $sameCounter; $i < count($secondPathParts); $i++) {
            $newPath .= DIRECTORY_SEPARATOR;
            $newPath .= $secondPathParts[$i];
        }
        //
        return $newPath;
    }

?>
richpageau at yahoo dot co dot uk
25-Jun-2007 08:55
This is my attempt at writing a realpath replacement. I needed to to run some Adobe code on a server with realpath disabled and this seemed to do the job. It is written for a unix server, I suppose it could be made cross platform using DIRECTORY_SEPARATOR. (With thanks to Marc Noirot for his code).

<?php
function myRealPath($path) {

    // check if path begins with "/" ie. is absolute
    // if it isnt concat with script path
    if (strpos($path,"/") !== 0) {
        $base=dirname($_SERVER['SCRIPT_FILENAME']);
        $path=$base."/".$path;
    }
 
    // canonicalize
    $path=explode('/', $path);
    $newpath=array();
    for ($i=0; $i<sizeof($path); $i++) {
        if ($path[$i]==='' || $path[$i]==='.') continue;
           if ($path[$i]==='..') {
              array_pop($newpath);
              continue;
        }
        array_push($newpath, $path[$i]);
    }
    $finalpath="/".implode('/', $newpath);

    // check then return valid path or filename
    if (file_exists($finalpath)) {
        return ($finalpath);
    }
    else return FALSE;
}
?>
David Beck
22-Nov-2006 05:38
Here's a function to canonicalize a URL containing relative paths. Ran into the problem when pulling links from a remote page.

<?php

function canonicalize($address)
{
    $address = explode('/', $address);
    $keys = array_keys($address, '..');

    foreach($keys AS $keypos => $key)
    {
        array_splice($address, $key - ($keypos * 2 + 1), 2);
    }

    $address = implode('/', $address);
    $address = str_replace('./', '', $address);
}

$url = 'http://www.example.com/something/../else';
echo canonicalize($url); //http://www.example.com/else

?>
bart at mediawave dot nl
21-Sep-2005 08:31
Here's another function that resolves references to '/./', '/../' and extra '/' characters in the input path and returns the canonicalized pathname.

<?php

function cleanPath($path) {
    $result = array();
    // $pathA = preg_split('/[\/\\\]/', $path);
    $pathA = explode('/', $path);
    if (!$pathA[0])
        $result[] = '';
    foreach ($pathA AS $key => $dir) {
        if ($dir == '..') {
            if (end($result) == '..') {
                $result[] = '..';
            } elseif (!array_pop($result)) {
                $result[] = '..';
            }
        } elseif ($dir && $dir != '.') {
            $result[] = $dir;
        }
    }
    if (!end($pathA))
        $result[] = '';
    return implode('/', $result);
}

echo 'input:  ', $path = '..//./../dir4//./dir5/dir6/..//dir7/', '<br />';
echo 'output: ', cleanPath($path), '<br />';

?>

Will return:

input:  ..//./../dir4//./dir5/dir6/..//dir7/
output: ../../dir4/dir5/dir7/
php.netatjulian-lemburg.de
20-Jul-2005 05:55
You have a realpath.
Now you want a htmlpath.

First Suggestion:
<?php

function htmlpath($relative_path) {
   $realpath=realpath($relative_path);
   $htmlpath=str_replace($_SERVER['DOCUMENT_ROOT'],'',$realpath);
   return $htmlpath;
}
?>

But this does not work on some servers.

Second Suggestion:

<?php

function htmlpath($realpath) {
   $i = substr_count($_ENV["SCRIPT_URL"],'/')."<br>";
   $baserealpath=realpath(str_repeat('../',$i-1));
   $htmlpath=str_replace($baserealpath,'',$realpath);
   return $htmlpath;
}

?>
Lars Scheithauer <l dot scheithauer at gmx dot de>
08-Jun-2005 07:44
This function is also nice to test for security-breaches. You can forbid the script to access files below a certain directory to prevent "../../../etc/shadow" and similar attacks:

<?php

// declare the basic directory for security reasons
// Please do NOT attach a "/"-suffix !
$basedir = '/var/www/cgi-bin/scriptfolder';

// compare the entered path with the basedir
$path_parts = pathinfo($_REQUEST['file_to_get']);
if (realpath($path_parts['dirname']) != $basedir) {
    /* appropriate action against crack-attempt*/
    die ('coding good - h4x1ng bad!');
}

?>

The url "script.php?file_to_get=../../../etc/shadow" will now result in an error.
pulstar at ig dot com dot br
20-Dec-2004 11:43
Sometimes you may need to refer to the absolute path of a file in your website instead of a relative path, but the realpath() function returns the path relative to the server's filesystem, not a path relative to your website root directory.

For example, realpath() may return something like this:

/home/yoursite/public_html/dir1/file.ext

You can't use this in an HTML document, because the web server will not find the file. To do so, you can use:

<?php

function htmlpath($relative_path) {
    $realpath=realpath($relative_path);
    $htmlpath=str_replace($_SERVER['DOCUMENT_ROOT'],'',$realpath);
    return $htmlpath;
}

echo '<img src="',htmlpath('../../relative/path/to/file.ext'),'" border=1>';

?>

It will return something like:

<img src="/dir1/relative/path/to/file.ext" border=1>
eric at themepark dot com
17-Jul-2002 03:15
note that realpath() will chop any trailing delimiter like \ or / ...don't forget to add it back on if you need it.

Eric Mueller - themepark.com
jemptyg at rwmc dot net
05-Jul-2001 12:38
realpath() seems to be equivalent to ASP's Server.MapPath.  On my Win2k box I have successfully used realpath() to give me the full path for a file outside of the document_root.  This will be very useful in conjunction with is_dir and/or is_file, which require a full path.
jerome at dot451 dot com
28-Aug-2000 09:03
mkdir (and realpath) did not work because i'd used virtual() function to replace server side include in my file.
And i've just seen that virtual() function changes the current directory ... that's why !

jerome ;)

rename> <realpath_cache_size
Last updated: Fri, 03 Feb 2012