PHP 8.4.0 RC4 available for testing

realpath

(PHP 4, PHP 5, PHP 7, PHP 8)

realpathReturns canonicalized absolute pathname

Опис

realpath(string $path): string|false

realpath() expands all symbolic links and resolves references to /./, /../ and extra / characters in the input path and returns the canonicalized absolute pathname.

Параметри

path

The path being checked.

Зауваження:

Whilst a path must be supplied, the value can be an empty string. In this case, the value is interpreted as the current directory.

Значення, що повертаються

Returns the canonicalized absolute pathname on success. The resulting path will have no symbolic link, /./ or /../ components. Trailing delimiters, such as \ and /, are also removed.

realpath() returns false on failure, e.g. if the file does not exist.

Зауваження:

The running script must have executable permissions on all directories in the hierarchy, otherwise realpath() will return false.

Зауваження:

For case-insensitive filesystems realpath() may or may not normalize the character case.

Зауваження:

The function realpath() will not work for a file which is inside a Phar as such path would be a virtual path, not a real one.

Зауваження:

On Windows, junctions and symbolic links to directories are only expanded by one level.

Зауваження: Оскільки цілочисельний тип в PHP є знаковим, а багато платформ використовують 32-бітні цілі числа, деякі функції файлової системи можуть повертати неочікувані результати для файлів, розмір яких перевищує 2 ГБ.

Приклади

Приклад #1 realpath() example

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

echo
realpath('/tmp/') . PHP_EOL;
?>

Поданий вище приклад виведе:

/etc/passwd
/tmp

Приклад #2 realpath() on Windows

On windows realpath() will change unix style paths to windows style.

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

echo
realpath('C:\Program Files\\'), PHP_EOL;
?>

Поданий вище приклад виведе:

C:\WINDOWS\System32
C:\Program Files

Прогляньте також

  • basename() - Повертає останній компонент рядка шляху
  • dirname() - Returns a parent directory's path
  • pathinfo() - Returns information about a file path

add a note

User Contributed Notes 17 notes

up
97
Sven Arduwie
16 years ago
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. :)
up
41
runeimp at gmail dot com
11 years ago
Needed a method to normalize a virtual path that could handle .. references that go beyond the initial folder reference. So I created the following.
<?php

function normalizePath($path)
{
$parts = array();// Array to build a new path from the good parts
$path = str_replace('\\', '/', $path);// Replace backslashes with forwardslashes
$path = preg_replace('/\/+/', '/', $path);// Combine multiple slashes into a single slash
$segments = explode('/', $path);// Collect path segments
$test = '';// Initialize testing variable
foreach($segments as $segment)
{
if(
$segment != '.')
{
$test = array_pop($parts);
if(
is_null($test))
$parts[] = $segment;
else if(
$segment == '..')
{
if(
$test == '..')
$parts[] = $test;

if(
$test == '..' || $test == '')
$parts[] = $segment;
}
else
{
$parts[] = $test;
$parts[] = $segment;
}
}
}
return
implode('/', $parts);
}
?>

Will convert /path/to/test/.././..//..///..///../one/two/../three/filename
to ../../one/three/filename
up
23
moreau dot marc dot web at gmail dot com
5 years ago
<?php

namespace MockingMagician\Organic\Helper;

class
Path
{
/**
* There is a method that deal with Sven Arduwie proposal https://www.php.net/manual/en/function.realpath.php#84012
* And runeimp at gmail dot com proposal https://www.php.net/manual/en/function.realpath.php#112367
* @param string $path
* @return string
*/
public static function getAbsolute(string $path): string
{
// Cleaning path regarding OS
$path = mb_ereg_replace('\\\\|/', DIRECTORY_SEPARATOR, $path, 'msr');
// Check if path start with a separator (UNIX)
$startWithSeparator = $path[0] === DIRECTORY_SEPARATOR;
// Check if start with drive letter
preg_match('/^[a-z]:/', $path, $matches);
$startWithLetterDir = isset($matches[0]) ? $matches[0] : false;
// Get and filter empty sub paths
$subPaths = array_filter(explode(DIRECTORY_SEPARATOR, $path), 'mb_strlen');

$absolutes = [];
foreach (
$subPaths as $subPath) {
if (
'.' === $subPath) {
continue;
}
// if $startWithSeparator is false
// and $startWithLetterDir
// and (absolutes is empty or all previous values are ..)
// save absolute cause that's a relative and we can't deal with that and just forget that we want go up
if ('..' === $subPath
&& !$startWithSeparator
&& !$startWithLetterDir
&& empty(array_filter($absolutes, function ($value) { return !('..' === $value); }))
) {
$absolutes[] = $subPath;
continue;
}
if (
'..' === $subPath) {
array_pop($absolutes);
continue;
}
$absolutes[] = $subPath;
}

return
((
$startWithSeparator ? DIRECTORY_SEPARATOR : $startWithLetterDir) ?
$startWithLetterDir.DIRECTORY_SEPARATOR : ''
).implode(DIRECTORY_SEPARATOR, $absolutes);
}

/**
* Examples
*
* echo Path::getAbsolute('/one/two/../two/./three/../../two'); => /one/two
* echo Path::getAbsolute('../one/two/../two/./three/../../two'); => ../one/two
* echo Path::getAbsolute('../.././../one/two/../two/./three/../../two'); => ../../../one/two
* echo Path::getAbsolute('../././../one/two/../two/./three/../../two'); => ../../one/two
* echo Path::getAbsolute('/../one/two/../two/./three/../../two'); => /one/two
* echo Path::getAbsolute('/../../one/two/../two/./three/../../two'); => /one/two
* echo Path::getAbsolute('c:\.\..\one\two\..\two\.\three\..\..\two'); => c:/one/two
*
*/
}
up
18
David Beck
17 years ago
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

?>
up
8
plamen at dragiyski dot org
5 years ago
realpath() is just a system/library call to actual realpath() function supported by OS. It does not work on a path as a string, but also resolves symlinks. The resulting path might significantly differs from the input even when absolute path is given. No function in this notes resolves that.

The suggestion on the realpath man page is to look for an existing parent directory. Here is an example:
<?php
function resolvePath($path) {
if(
DIRECTORY_SEPARATOR !== '/') {
$path = str_replace(DIRECTORY_SEPARATOR, '/', $path);
}
$search = explode('/', $path);
$search = array_filter($search, function($part) {
return
$part !== '.';
});
$append = array();
$match = false;
while(
count($search) > 0) {
$match = realpath(implode('/', $search));
if(
$match !== false) {
break;
}
array_unshift($append, array_pop($search));
};
if(
$match === false) {
$match = getcwd();
}
if(
count($append) > 0) {
$match .= DIRECTORY_SEPARATOR . implode(DIRECTORY_SEPARATOR, $append);
}
return
$match;
}
?>

The result will retrieve absolute path for non-existing relative path. Even if a path does not exists, there should be existing directory somewhere, for which the realpath could be obtained. If this is not within the relative path (i.e. even current working directory does not exists), getcwd() will retrieve absolute path, so some absolute path is returned (although in that case the PHP process could have huge problems).
up
25
Anonymous
12 years ago
Note: If you use this to check if a file exists, it's path will be cached, and returns true even if the file is removed (use file_exists instead).
up
10
pulstar at ig dot com dot br
19 years ago
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>
up
7
Jrg Wagner
14 years ago
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\\"
up
6
https://stackoverflow.com/users/1397947/
7 years ago
It should probably be expressly noted that tilde expansion is not performed by realpath.
up
5
Vincent Par
9 years ago
Beware of relative symbolic links like this one (ext4 file system on Ubuntu) :

vincent@vincent:~/Bureau/dirscan$ readlink sandbox/roulant/voiture/cabriolet/ln-loop-relative
../..

In this case, realpath may return false :

<?php
var_dump
(realpath('sandbox/roulant/voiture/cabriolet/ln-loop-relative'));
// => string(44) "/home/vincent/Bureau/dirscan/sandbox/roulant"
var_dump(realpath('sandbox/roulant/voiture/cabriolet/ln-loop-relative/moto'));
// => bool(false)
?>

But you can fix it by clearing the realpath cache, this way :

<?php
var_dump
(realpath('sandbox/roulant/voiture/cabriolet/ln-loop-relative'));
clearstatcache(true);
var_dump(realpath('sandbox/roulant/voiture/cabriolet/ln-loop-relative/moto'));
// => string(49) "/home/vincent/Bureau/dirscan/sandbox/roulant/moto"
?>
up
7
imagiro
13 years ago
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, $arTo);
}
?>
up
3
eion at robbmob dot com
8 years ago
Be aware that realpath() doesn't work with hidden Windows UNC paths, eg \\servername\share$\folder\blah.txt but other PHP file-functions can access that file fine.
up
2
Lars Scheithauer <l dot scheithauer at gmx dot de>
19 years ago
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.
up
2
php at keith tyler dot com
13 years ago
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.
up
2
Leonard Challis
11 years ago
When using realpath (and similar functions) remember that PHP will take in to account open_basedir restrictions. So, if you do something like:

<?php
// test.php in httpdocs folder
$path = realpath(dirname(__FILE__) . '/../application');
?>

where your open_basedir setting is set to the httpdocs folder and tmp, this will return false. You must set it to the level above (or off) for this to work.
up
0
belisoful at icloud dot com
1 year ago
Sven Arduwie answer is not tested and does not replicate the behavior of realpath but is a close solution.

This has been unit tested to be as close to realpath as possible but without the path having to actually exist in the system.

This takes relative paths and realizes them properly based on actual current working directory, but everything can be virtual. eg. "../someVirtualDir/./virtualFile.jpg"

<?php

public static function virtualpath($path): string
{
$path = str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $path);
$len = strlen($path);
$relative = strpos($path, DIRECTORY_SEPARATOR);
if (!
$len || ($len > 0 && $path[0] == '.') || $relative !== 0) {
$path = getcwd() . DIRECTORY_SEPARATOR . $path;
}
$parts = array_filter(explode(DIRECTORY_SEPARATOR, $path), 'strlen');
$absolutes = [];
foreach (
$parts as $part) {
if (
'.' == $part) {
continue;
}
if (
'..' == $part) {
array_pop($absolutes);
} else {
$absolutes[] = $part;
}
}
return
DIRECTORY_SEPARATOR . implode(DIRECTORY_SEPARATOR, $absolutes);
}

?>
up
-2
Enzo dot Barbaguelatta at alma dot cl
2 years ago
Be noticed that, one of the reasons of realtpath retuning false can be if the path does not exist, or it has permission issues, or even if security modules of your operating system (let's say, SELinux for example) avoids you checking the path.

If you're like me and you had a not very good time checking why realpath retuns false, please check these points first.
To Top