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, $absolutes);
}
?>
A test:
<?php
var_dump(get_absolute_path('this/is/../a/./test/.///is'));
?>
Returns: string(14) "this/a/test/is"
As you can so, it also produces Yoda-speak. :)
realpath
(PHP 4, PHP 5, PHP 7, PHP 8)
realpath — 返回规范化的绝对路径名
说明
realpath() 扩展所有符号连接，并处理输入
path 中的 /./、/../ 和多余的
/，并返回规范化的绝对路径名。
参数
-
path -
要处理的路径。
注意:
虽然必须提供路径，但该值可以是一个空字符串。 在这种情况下，该值将被解释为当前目录。
返回值
成功时返回规范化的绝对路径名。返回的路径中没有符号连接（symbolic link）、/./ 或 /../ 成分。
例如 \ 和 / 这样的尾随分隔符也将被删除。
realpath() 失败时返回 false，例如文件不存在。
注意:
当前运行的脚本必须对要处理的路径中的每层目录都具有可执行权限，否则 realpath() 将返回
false。
注意:
对于不区分大小写的文件系统，realpath() 不一定会规范字符大小写。
注意:
realpath() 函数不适用于 Phar 内的文件，因为该路径是虚拟路径，而不是真实路径。
注意:
在 Windows 上，目录的结点和符号链接仅扩展一级。
注意: 因为 PHP 的整数类型是有符号整型而且很多平台使用 32 位整型，对 2GB 以上的文件，一些文件系统函数可能返回无法预期的结果。
示例
示例 #1 realpath() 例子
<?php
chdir('/var/www/');
echo realpath('./../../etc/passwd') . PHP_EOL;
echo realpath('/tmp/') . PHP_EOL;
?>以上示例会输出：
/etc/passwd /tmp
示例 #2 Windows 上的 realpath()
在 Windows 上，realpath() 会将 unix 风格的路径改成 Windows 风格。
<?php
echo realpath('/windows/system32'), PHP_EOL;
echo realpath('C:\Program Files\\'), PHP_EOL;
?>以上示例会输出：
C:\WINDOWS\System32 C:\Program Files
add a note
User Contributed Notes 17 notes
Sven Arduwie ¶
16 years ago
runeimp at gmail dot com ¶
11 years ago
Needed a method to normalize a virtual path that could handle .. references that go beyond the initial folder reference. So I created the following.
<?php
function normalizePath($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
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, $absolutes);
}
/**
* Examples
*
* echo Path::getAbsolute('/one/two/../two/./three/../../two'); => /one/two
* echo Path::getAbsolute('../one/two/../two/./three/../../two'); => ../one/two
* echo Path::getAbsolute('../.././../one/two/../two/./three/../../two'); => ../../../one/two
* echo Path::getAbsolute('../././../one/two/../two/./three/../../two'); => ../../one/two
* echo Path::getAbsolute('/../one/two/../two/./three/../../two'); => /one/two
* echo Path::getAbsolute('/../../one/two/../two/./three/../../two'); => /one/two
* echo Path::getAbsolute('c:\.\..\one\two\..\two\.\three\..\..\two'); => c:/one/two
*
*/
}
Anonymous ¶
12 years ago
Note: If you use this to check if a file exists, it's path will be cached, and returns true even if the file is removed (use file_exists instead).
David Beck ¶
18 years ago
Here's a function to canonicalize a URL containing relative paths. Ran into the problem when pulling links from a remote page.
<?php
function canonicalize($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
?>
pulstar at ig dot com dot br ¶
20 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 $htmlpath;
}
echo '<img src="',htmlpath('../../relative/path/to/file.ext'),'" border=1>';
?>
It will return something like:
<img src="/dir1/relative/path/to/file.ext" border=1>
plamen at dragiyski dot org ¶
5 years ago
realpath() is just a system/library call to actual realpath() function supported by OS. It does not work on a path as a string, but also resolves symlinks. The resulting path might significantly differs from the input even when absolute path is given. No function in this notes resolves that.
The suggestion on the realpath man page is to look for an existing parent directory. Here is an example:
<?php
function resolvePath($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 $match;
}
?>
The result will retrieve absolute path for non-existing relative path. Even if a path does not exists, there should be existing directory somewhere, for which the realpath could be obtained. If this is not within the relative path (i.e. even current working directory does not exists), getcwd() will retrieve absolute path, so some absolute path is returned (although in that case the PHP process could have huge problems).
Jrg Wagner ¶
14 years ago
Please be aware that this function does NOT always strip a trailing slash!:
LINUX (tested with PHP 5.2.11):
---
realpath('.')
: string = "/myhttpdfolder"
realpath('./')
: string = "/myhttpdfolder"
realpath('fileadmin')
: string = "/myhttpdfolder/fileadmin"
realpath('fileadmin/')
: string = "/myhttpdfolder/fileadmin"
WINDOWS (tested with PHP 5.2.5):
---
realpath('.')
: string = "C:\\myhttpdfolder"
realpath('./')
: string = "C:\\myhttpdfolder\\"
realpath('fileadmin')
: string = "C:\\myhttpdfolder\\fileadmin"
realpath('fileadmin/')
: string = "C:\\myhttpdfolder\\fileadmin\\"
https://stackoverflow.com/users/1397947/ ¶
7 years ago
It should probably be expressly noted that tilde expansion is not performed by realpath.
Vincent Par ¶
9 years ago
Beware of relative symbolic links like this one (ext4 file system on Ubuntu) :
vincent@vincent:~/Bureau/dirscan$ 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"
?>
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, $arTo);
}
?>
eion at robbmob dot com ¶
9 years ago
Be aware that realpath() doesn't work with hidden Windows UNC paths, eg \\servername\share$\folder\blah.txt but other PHP file-functions can access that file fine.
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.
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.
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
$path = realpath(dirname(__FILE__) . '/../application');
?>
where your open_basedir setting is set to the httpdocs folder and tmp, this will return false. You must set it to the level above (or off) for this to work.
belisoful at icloud dot com ¶
1 year ago
Sven Arduwie answer is not tested and does not replicate the behavior of realpath but is a close solution.
This has been unit tested to be as close to realpath as possible but without the path having to actually exist in the system.
This takes relative paths and realizes them properly based on actual current working directory, but everything can be virtual. eg. "../someVirtualDir/./virtualFile.jpg"
<?php
public static function virtualpath($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);
}
?>
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.
